Initial stab at Venti.

52 files changed, 9527 insertions, 0 deletions

diff --git a/src/cmd/venti/arena.c b/src/cmd/venti/arena.c
new file mode 100644
index 00000000..4a59b278
--- /dev/null
+++ b/src/cmd/venti/arena.c
@@ -0,0 +1,641 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+typedef struct ASum ASum;
+
+struct ASum
+{
+	Arena	*arena;
+	ASum	*next;
+};
+
+static void	sealarena(Arena *arena);
+static int	okarena(Arena *arena);
+static int	loadarena(Arena *arena);
+static CIBlock	*getcib(Arena *arena, int clump, int writing, CIBlock *rock);
+static void	putcib(Arena *arena, CIBlock *cib);
+static void	sumproc(void *);
+
+static QLock	sumlock;
+static Rendez	sumwait;
+static ASum	*sumq;
+
+int
+initarenasum(void)
+{
+	sumwait.l = &sumlock;
+
+	if(vtproc(sumproc, nil) < 0){
+		seterr(EOk, "can't start arena checksum slave: %r");
+		return -1;
+	}
+	return 0;
+}
+
+/*
+ * make an Arena, and initialize it based upon the disk header and trailer.
+ */
+Arena*
+initarena(Part *part, u64int base, u64int size, u32int blocksize)
+{
+	Arena *arena;
+
+	arena = MKZ(Arena);
+	arena->part = part;
+	arena->blocksize = blocksize;
+	arena->clumpmax = arena->blocksize / ClumpInfoSize;
+	arena->base = base + blocksize;
+	arena->size = size - 2 * blocksize;
+
+	if(loadarena(arena) < 0){
+		seterr(ECorrupt, "arena header or trailer corrupted");
+		freearena(arena);
+		return nil;
+	}
+	if(okarena(arena) < 0){
+		freearena(arena);
+		return nil;
+	}
+
+	if(arena->sealed && scorecmp(zeroscore, arena->score)==0)
+		backsumarena(arena);
+
+	return arena;
+}
+
+void
+freearena(Arena *arena)
+{
+	if(arena == nil)
+		return;
+	if(arena->cib.data != nil){
+		putdblock(arena->cib.data);
+		arena->cib.data = nil;
+	}
+	free(arena);
+}
+
+Arena*
+newarena(Part *part, char *name, u64int base, u64int size, u32int blocksize)
+{
+	Arena *arena;
+
+	if(nameok(name) < 0){
+		seterr(EOk, "illegal arena name", name);
+		return nil;
+	}
+	arena = MKZ(Arena);
+	arena->part = part;
+	arena->version = ArenaVersion;
+	arena->blocksize = blocksize;
+	arena->clumpmax = arena->blocksize / ClumpInfoSize;
+	arena->base = base + blocksize;
+	arena->size = size - 2 * blocksize;
+
+	namecp(arena->name, name);
+
+	if(wbarena(arena)<0 || wbarenahead(arena)<0){
+		freearena(arena);
+		return nil;
+	}
+
+	return arena;
+}
+
+int
+readclumpinfo(Arena *arena, int clump, ClumpInfo *ci)
+{
+	CIBlock *cib, r;
+
+	cib = getcib(arena, clump, 0, &r);
+	if(cib == nil)
+		return -1;
+	unpackclumpinfo(ci, &cib->data->data[cib->offset]);
+	putcib(arena, cib);
+	return 0;
+}
+
+int
+readclumpinfos(Arena *arena, int clump, ClumpInfo *cis, int n)
+{
+	CIBlock *cib, r;
+	int i;
+
+	for(i = 0; i < n; i++){
+		cib = getcib(arena, clump + i, 0, &r);
+		if(cib == nil)
+			break;
+		unpackclumpinfo(&cis[i], &cib->data->data[cib->offset]);
+		putcib(arena, cib);
+	}
+	return i;
+}
+
+/*
+ * write directory information for one clump
+ * must be called the arena locked
+ */
+int
+writeclumpinfo(Arena *arena, int clump, ClumpInfo *ci)
+{
+	CIBlock *cib, r;
+
+	cib = getcib(arena, clump, 1, &r);
+	if(cib == nil)
+		return -1;
+	packclumpinfo(ci, &cib->data->data[cib->offset]);
+	putcib(arena, cib);
+	return 0;
+}
+
+u64int
+arenadirsize(Arena *arena, u32int clumps)
+{
+	return ((clumps / arena->clumpmax) + 1) * arena->blocksize;
+}
+
+/*
+ * read a clump of data
+ * n is a hint of the size of the data, not including the header
+ * make sure it won't run off the end, then return the number of bytes actually read
+ */
+u32int
+readarena(Arena *arena, u64int aa, u8int *buf, long n)
+{
+	DBlock *b;
+	u64int a;
+	u32int blocksize, off, m;
+	long nn;
+
+	if(n == 0)
+		return -1;
+
+	qlock(&arena->lock);
+	a = arena->size - arenadirsize(arena, arena->clumps);
+	qunlock(&arena->lock);
+	if(aa >= a){
+		seterr(EOk, "reading beyond arena clump storage: clumps=%d aa=%lld a=%lld -1 clumps=%lld\n", arena->clumps, aa, a, arena->size - arenadirsize(arena, arena->clumps - 1));
+		return -1;
+	}
+	if(aa + n > a)
+		n = a - aa;
+
+	blocksize = arena->blocksize;
+	a = arena->base + aa;
+	off = a & (blocksize - 1);
+	a -= off;
+	nn = 0;
+	for(;;){
+		b = getdblock(arena->part, a, 1);
+		if(b == nil)
+			return -1;
+		m = blocksize - off;
+		if(m > n - nn)
+			m = n - nn;
+		memmove(&buf[nn], &b->data[off], m);
+		putdblock(b);
+		nn += m;
+		if(nn == n)
+			break;
+		off = 0;
+		a += blocksize;
+	}
+	return n;
+}
+
+/*
+ * write some data to the clump section at a given offset
+ * used to fix up corrupted arenas.
+ */
+u32int
+writearena(Arena *arena, u64int aa, u8int *clbuf, u32int n)
+{
+	DBlock *b;
+	u64int a;
+	u32int blocksize, off, m;
+	long nn;
+	int ok;
+
+	if(n == 0)
+		return -1;
+
+	qlock(&arena->lock);
+	a = arena->size - arenadirsize(arena, arena->clumps);
+	if(aa >= a || aa + n > a){
+		qunlock(&arena->lock);
+		seterr(EOk, "writing beyond arena clump storage");
+		return -1;
+	}
+
+	blocksize = arena->blocksize;
+	a = arena->base + aa;
+	off = a & (blocksize - 1);
+	a -= off;
+	nn = 0;
+	for(;;){
+		b = getdblock(arena->part, a, off != 0 || off + n < blocksize);
+		if(b == nil){
+			qunlock(&arena->lock);
+			return -1;
+		}
+		m = blocksize - off;
+		if(m > n - nn)
+			m = n - nn;
+		memmove(&b->data[off], &clbuf[nn], m);
+		ok = writepart(arena->part, a, b->data, blocksize);
+		putdblock(b);
+		if(ok < 0){
+			qunlock(&arena->lock);
+			return -1;
+		}
+		nn += m;
+		if(nn == n)
+			break;
+		off = 0;
+		a += blocksize;
+	}
+	qunlock(&arena->lock);
+	return n;
+}
+
+/*
+ * allocate space for the clump and write it,
+ * updating the arena directory
+ZZZ question: should this distinguish between an arena
+filling up and real errors writing the clump?
+ */
+u64int
+writeaclump(Arena *arena, Clump *c, u8int *clbuf)
+{
+	DBlock *b;
+	u64int a, aa;
+	u32int clump, n, nn, m, off, blocksize;
+	int ok;
+
+	n = c->info.size + ClumpSize;
+	qlock(&arena->lock);
+	aa = arena->used;
+	if(arena->sealed
+	|| aa + n + U32Size + arenadirsize(arena, arena->clumps + 1) > arena->size){
+		if(!arena->sealed)
+			sealarena(arena);
+		qunlock(&arena->lock);
+		return TWID64;
+	}
+	if(packclump(c, &clbuf[0]) < 0){
+		qunlock(&arena->lock);
+		return TWID64;
+	}
+
+	/*
+	 * write the data out one block at a time
+	 */
+	blocksize = arena->blocksize;
+	a = arena->base + aa;
+	off = a & (blocksize - 1);
+	a -= off;
+	nn = 0;
+	for(;;){
+		b = getdblock(arena->part, a, off != 0);
+		if(b == nil){
+			qunlock(&arena->lock);
+			return TWID64;
+		}
+		m = blocksize - off;
+		if(m > n - nn)
+			m = n - nn;
+		memmove(&b->data[off], &clbuf[nn], m);
+print("writing\n");
+		ok = writepart(arena->part, a, b->data, blocksize);
+		putdblock(b);
+		if(ok < 0){
+			qunlock(&arena->lock);
+			return TWID64;
+		}
+		nn += m;
+		if(nn == n)
+			break;
+		off = 0;
+		a += blocksize;
+	}
+
+	arena->used += c->info.size + ClumpSize;
+	arena->uncsize += c->info.uncsize;
+	if(c->info.size < c->info.uncsize)
+		arena->cclumps++;
+
+	clump = arena->clumps++;
+	if(arena->clumps == 0)
+		sysfatal("clumps wrapped\n");
+	arena->wtime = now();
+	if(arena->ctime == 0)
+		arena->ctime = arena->wtime;
+
+	writeclumpinfo(arena, clump, &c->info);
+//ZZZ make this an enum param
+	if((clump & 0x1ff) == 0x1ff){
+		flushciblocks(arena);
+		wbarena(arena);
+	}
+
+	qunlock(&arena->lock);
+	return aa;
+}
+
+/*
+ * once sealed, an arena never has any data added to it.
+ * it should only be changed to fix errors.
+ * this also syncs the clump directory.
+ */
+static void
+sealarena(Arena *arena)
+{
+	flushciblocks(arena);
+	arena->sealed = 1;
+	wbarena(arena);
+	backsumarena(arena);
+}
+
+void
+backsumarena(Arena *arena)
+{
+	ASum *as;
+
+	as = MK(ASum);
+	if(as == nil)
+		return;
+	qlock(&sumlock);
+	as->arena = arena;
+	as->next = sumq;
+	sumq = as;
+	rwakeup(&sumwait);
+	qunlock(&sumlock);
+}
+
+static void
+sumproc(void *unused)
+{
+	ASum *as;
+	Arena *arena;
+
+	USED(unused);
+
+	for(;;){
+		qlock(&sumlock);
+		while(sumq == nil)
+			rsleep(&sumwait);
+		as = sumq;
+		sumq = as->next;
+		qunlock(&sumlock);
+		arena = as->arena;
+		free(as);
+
+		sumarena(arena);
+	}
+}
+
+void
+sumarena(Arena *arena)
+{
+	ZBlock *b;
+	DigestState s;
+	u64int a, e;
+	u32int bs;
+	u8int score[VtScoreSize];
+
+	bs = MaxIoSize;
+	if(bs < arena->blocksize)
+		bs = arena->blocksize;
+
+	/*
+	 * read & sum all blocks except the last one
+	 */
+	memset(&s, 0, sizeof s);
+	b = alloczblock(bs, 0);
+	e = arena->base + arena->size;
+	for(a = arena->base - arena->blocksize; a + arena->blocksize <= e; a += bs){
+		if(a + bs > e)
+			bs = arena->blocksize;
+		if(readpart(arena->part, a, b->data, bs) < 0)
+			goto ReadErr;
+		sha1(b->data, bs, nil, &s);
+	}
+
+	/*
+	 * the last one is special, since it may already have the checksum included
+	 */
+	bs = arena->blocksize;
+	if(readpart(arena->part, e, b->data, bs) < 0){
+ReadErr:
+		logerr(EOk, "sumarena can't sum %s, read at %lld failed: %r", arena->name, a);
+		freezblock(b);
+		return;
+	}
+
+	sha1(b->data, bs-VtScoreSize, nil, &s);
+	sha1(zeroscore, VtScoreSize, nil, &s);
+	sha1(nil, 0, score, &s);
+
+	/*
+	 * check for no checksum or the same
+	 */
+	if(scorecmp(score, &b->data[bs - VtScoreSize]) != 0){
+		if(scorecmp(zeroscore, &b->data[bs - VtScoreSize]) != 0)
+			logerr(EOk, "overwriting mismatched checksums for arena=%s, found=%V calculated=%V",
+				arena->name, &b->data[bs - VtScoreSize], score);
+		scorecp(&b->data[bs - VtScoreSize], score);
+		if(writepart(arena->part, e, b->data, bs) < 0)
+			logerr(EOk, "sumarena can't write sum for %s: %r", arena->name);
+	}
+	freezblock(b);
+
+	qlock(&arena->lock);
+	scorecp(arena->score, score);
+	qunlock(&arena->lock);
+}
+
+/*
+ * write the arena trailer block to the partition
+ */
+int
+wbarena(Arena *arena)
+{
+	ZBlock *b;
+	int bad;
+
+	b = alloczblock(arena->blocksize, 1);
+	if(b == nil){
+		logerr(EAdmin, "can't write arena trailer: %r");
+///ZZZ add error message?
+		return -1;
+	}
+	bad = okarena(arena)<0 || packarena(arena, b->data)<0 || 
+		writepart(arena->part, arena->base + arena->size, b->data, arena->blocksize)<0;
+	freezblock(b);
+	if(bad)
+		return -1;
+	return 0;
+}
+
+int
+wbarenahead(Arena *arena)
+{
+	ZBlock *b;
+	ArenaHead head;
+	int bad;
+
+	namecp(head.name, arena->name);
+	head.version = arena->version;
+	head.size = arena->size + 2 * arena->blocksize;
+	head.blocksize = arena->blocksize;
+	b = alloczblock(arena->blocksize, 1);
+	if(b == nil){
+		logerr(EAdmin, "can't write arena header: %r");
+///ZZZ add error message?
+		return -1;
+	}
+	bad = packarenahead(&head, b->data)<0 ||
+	      writepart(arena->part, arena->base - arena->blocksize, b->data, arena->blocksize)<0;
+	freezblock(b);
+	if(bad)
+		return -1;
+	return 0;
+}
+
+/*
+ * read the arena header and trailer blocks from disk
+ */
+static int
+loadarena(Arena *arena)
+{
+	ArenaHead head;
+	ZBlock *b;
+
+	b = alloczblock(arena->blocksize, 0);
+	if(b == nil)
+		return -1;
+	if(readpart(arena->part, arena->base + arena->size, b->data, arena->blocksize) < 0){
+		freezblock(b);
+		return -1;
+	}
+	if(unpackarena(arena, b->data) < 0){
+		freezblock(b);
+		return -1;
+	}
+	if(arena->version != ArenaVersion){
+		seterr(EAdmin, "unknown arena version %d", arena->version);
+		freezblock(b);
+		return -1;
+	}
+	scorecp(arena->score, &b->data[arena->blocksize - VtScoreSize]);
+
+	if(readpart(arena->part, arena->base - arena->blocksize, b->data, arena->blocksize) < 0){
+		logerr(EAdmin, "can't read arena header: %r");
+		freezblock(b);
+		return 0;
+	}
+	if(unpackarenahead(&head, b->data) < 0)
+		logerr(ECorrupt, "corrupted arena header: %r");
+	else if(namecmp(arena->name, head.name)!=0
+	     || arena->version != head.version
+	     || arena->blocksize != head.blocksize
+	     || arena->size + 2 * arena->blocksize != head.size)
+		logerr(ECorrupt, "arena header inconsistent with arena data");
+	freezblock(b);
+
+	return 0;
+}
+
+static int
+okarena(Arena *arena)
+{
+	u64int dsize;
+	int ok;
+
+	ok = 0;
+	dsize = arenadirsize(arena, arena->clumps);
+	if(arena->used + dsize > arena->size){
+		seterr(ECorrupt, "arena used > size");
+		ok = -1;
+	}
+
+	if(arena->cclumps > arena->clumps)
+		logerr(ECorrupt, "arena has more compressed clumps than total clumps");
+
+	if(arena->uncsize + arena->clumps * ClumpSize + arena->blocksize < arena->used)
+		logerr(ECorrupt, "arena uncompressed size inconsistent with used space %lld %d %lld", arena->uncsize, arena->clumps, arena->used);
+
+	if(arena->ctime > arena->wtime)
+		logerr(ECorrupt, "arena creation time after last write time");
+
+	return ok;
+}
+
+static CIBlock*
+getcib(Arena *arena, int clump, int writing, CIBlock *rock)
+{
+	CIBlock *cib;
+	u32int block, off;
+
+	if(clump >= arena->clumps){
+		seterr(EOk, "clump directory access out of range");
+		return nil;
+	}
+	block = clump / arena->clumpmax;
+	off = (clump - block * arena->clumpmax) * ClumpInfoSize;
+
+	if(arena->cib.block == block
+	&& arena->cib.data != nil){
+		arena->cib.offset = off;
+		return &arena->cib;
+	}
+
+	if(writing){
+		flushciblocks(arena);
+		cib = &arena->cib;
+	}else
+		cib = rock;
+
+	qlock(&stats.lock);
+	stats.cireads++;
+	qunlock(&stats.lock);
+
+	cib->block = block;
+	cib->offset = off;
+	cib->data = getdblock(arena->part, arena->base + arena->size - (block + 1) * arena->blocksize, arena->blocksize);
+	if(cib->data == nil)
+		return nil;
+	return cib;
+}
+
+static void
+putcib(Arena *arena, CIBlock *cib)
+{
+	if(cib != &arena->cib){
+		putdblock(cib->data);
+		cib->data = nil;
+	}
+}
+
+/*
+ * must be called with arena locked
+ */
+int
+flushciblocks(Arena *arena)
+{
+	int ok;
+
+	if(arena->cib.data == nil)
+		return 0;
+	qlock(&stats.lock);
+	stats.ciwrites++;
+	qunlock(&stats.lock);
+	ok = writepart(arena->part, arena->base + arena->size - (arena->cib.block + 1) * arena->blocksize, arena->cib.data->data, arena->blocksize);
+
+	if(ok < 0)
+		seterr(EAdmin, "failed writing arena directory block");
+	putdblock(arena->cib.data);
+	arena->cib.data = nil;
+	return ok;
+}
diff --git a/src/cmd/venti/arenas.c b/src/cmd/venti/arenas.c
new file mode 100644
index 00000000..5275b938
--- /dev/null
+++ b/src/cmd/venti/arenas.c
@@ -0,0 +1,404 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+typedef struct AHash	AHash;
+
+/*
+ * hash table for finding arena's based on their names.
+ */
+struct AHash
+{
+	AHash	*next;
+	Arena	*arena;
+};
+
+enum
+{
+	AHashSize	= 512
+};
+
+static AHash	*ahash[AHashSize];
+
+static u32int
+hashstr(char *s)
+{
+	u32int h;
+	int c;
+
+	h = 0;
+	for(; c = *s; s++){
+		c ^= c << 6;
+		h += (c << 11) ^ (c >> 1);
+		c = *s;
+		h ^= (c << 14) + (c << 7) + (c << 4) + c;
+	}
+	return h;
+}
+
+int
+addarena(Arena *arena)
+{
+	AHash *a;
+	u32int h;
+
+	h = hashstr(arena->name) & (AHashSize - 1);
+	a = MK(AHash);
+	if(a == nil)
+		return -1;
+	a->arena = arena;
+	a->next = ahash[h];
+	ahash[h] = a;
+	return 0;
+}
+
+Arena*
+findarena(char *name)
+{
+	AHash *a;
+	u32int h;
+
+	h = hashstr(name) & (AHashSize - 1);
+	for(a = ahash[h]; a != nil; a = a->next)
+		if(strcmp(a->arena->name, name) == 0)
+			return a->arena;
+	return nil;
+}
+
+int
+delarena(Arena *arena)
+{
+	AHash *a, *last;
+	u32int h;
+
+	h = hashstr(arena->name) & (AHashSize - 1);
+	last = nil;
+	for(a = ahash[h]; a != nil; a = a->next){
+		if(a->arena == arena){
+			if(last != nil)
+				last->next = a->next;
+			else
+				ahash[h] = a->next;
+			free(a);
+			return 0;
+		}
+		last = a;
+	}
+	return -1;
+}
+
+ArenaPart*
+initarenapart(Part *part)
+{
+	AMapN amn;
+	ArenaPart *ap;
+	ZBlock *b;
+	u32int i;
+	int ok;
+
+	b = alloczblock(HeadSize, 0);
+	if(b == nil || readpart(part, PartBlank, b->data, HeadSize) < 0){
+		seterr(EAdmin, "can't read arena partition header: %r");
+		return nil;
+	}
+
+	ap = MKZ(ArenaPart);
+	if(ap == nil){
+		freezblock(b);
+		return nil;
+	}
+	ap->part = part;
+	ok = unpackarenapart(ap, b->data);
+	freezblock(b);
+	if(ok < 0){
+		seterr(ECorrupt, "corrupted arena partition header: %r");
+		freearenapart(ap, 0);
+		return nil;
+	}
+
+	ap->tabbase = (PartBlank + HeadSize + ap->blocksize - 1) & ~(ap->blocksize - 1);
+	if(ap->version != ArenaPartVersion){
+		seterr(ECorrupt, "unknown arena partition version %d", ap->version);
+		freearenapart(ap, 0);
+		return nil;
+	}
+	if(ap->blocksize & (ap->blocksize - 1)){
+		seterr(ECorrupt, "illegal non-power-of-2 block size %d\n", ap->blocksize);
+		freearenapart(ap, 0);
+		return nil;
+	}
+	if(ap->tabbase >= ap->arenabase){
+		seterr(ECorrupt, "arena partition table overlaps with arena storage");
+		freearenapart(ap, 0);
+		return nil;
+	}
+	ap->tabsize = ap->arenabase - ap->tabbase;
+	partblocksize(part, ap->blocksize);
+	ap->size = ap->part->size & ~(u64int)(ap->blocksize - 1);
+
+	if(readarenamap(&amn, part, ap->tabbase, ap->tabsize) < 0){
+		freearenapart(ap, 0);
+		return nil;
+	}
+	ap->narenas = amn.n;
+	ap->map = amn.map;
+	if(okamap(ap->map, ap->narenas, ap->arenabase, ap->size, "arena table") < 0){
+		freearenapart(ap, 0);
+		return nil;
+	}
+
+	ap->arenas = MKNZ(Arena*, ap->narenas);
+	for(i = 0; i < ap->narenas; i++){
+		ap->arenas[i] = initarena(part, ap->map[i].start, ap->map[i].stop - ap->map[i].start, ap->blocksize);
+		if(ap->arenas[i] == nil){
+			freearenapart(ap, 1);
+			return nil;
+		}
+		if(namecmp(ap->map[i].name, ap->arenas[i]->name) != 0){
+			seterr(ECorrupt, "arena name mismatches with expected name: %s vs. %s",
+				ap->map[i].name, ap->arenas[i]->name);
+			freearenapart(ap, 1);
+			return nil;
+		}
+		if(findarena(ap->arenas[i]->name)){
+			seterr(ECorrupt, "duplicate arena name %s in %s",
+				ap->map[i].name, ap->part->name);
+			freearenapart(ap, 1);
+			return nil;
+		}
+	}
+
+	for(i = 0; i < ap->narenas; i++)
+		addarena(ap->arenas[i]);
+
+	return ap;
+}
+
+ArenaPart*
+newarenapart(Part *part, u32int blocksize, u32int tabsize)
+{
+	ArenaPart *ap;
+
+	if(blocksize & (blocksize - 1)){
+		seterr(ECorrupt, "illegal non-power-of-2 block size %d\n", blocksize);
+		return nil;
+	}
+	ap = MKZ(ArenaPart);
+	if(ap == nil)
+		return nil;
+
+	ap->version = ArenaPartVersion;
+	ap->part = part;
+	ap->blocksize = blocksize;
+	partblocksize(part, blocksize);
+	ap->size = part->size & ~(u64int)(blocksize - 1);
+	ap->tabbase = (PartBlank + HeadSize + blocksize - 1) & ~(blocksize - 1);
+	ap->arenabase = (ap->tabbase + tabsize + blocksize - 1) & ~(blocksize - 1);
+	ap->tabsize = ap->arenabase - ap->tabbase;
+	ap->narenas = 0;
+
+	if(wbarenapart(ap) < 0){
+		freearenapart(ap, 0);
+		return nil;
+	}
+
+	return ap;
+}
+
+int
+wbarenapart(ArenaPart *ap)
+{
+	ZBlock *b;
+
+	if(okamap(ap->map, ap->narenas, ap->arenabase, ap->size, "arena table") < 0)
+		return -1;
+	b = alloczblock(HeadSize, 1);
+	if(b == nil)
+//ZZZ set error message?
+		return -1;
+
+	if(packarenapart(ap, b->data) < 0){
+		seterr(ECorrupt, "can't make arena partition header: %r");
+		freezblock(b);
+		return -1;
+	}
+	if(writepart(ap->part, PartBlank, b->data, HeadSize) < 0){
+		seterr(EAdmin, "can't write arena partition header: %r");
+		freezblock(b);
+		return -1;
+	}
+	freezblock(b);
+
+	return wbarenamap(ap->map, ap->narenas, ap->part, ap->tabbase, ap->tabsize);
+}
+
+void
+freearenapart(ArenaPart *ap, int freearenas)
+{
+	int i;
+
+	if(ap == nil)
+		return;
+	if(freearenas){
+		for(i = 0; i < ap->narenas; i++){
+			if(ap->arenas[i] == nil)
+				continue;
+			delarena(ap->arenas[i]);
+			freearena(ap->arenas[i]);
+		}
+	}
+	free(ap->map);
+	free(ap->arenas);
+	free(ap);
+}
+
+int
+okamap(AMap *am, int n, u64int start, u64int stop, char *what)
+{
+	u64int last;
+	u32int i;
+
+	last = start;
+	for(i = 0; i < n; i++){
+		if(am[i].start < last){
+			if(i == 0)
+				seterr(ECorrupt, "invalid start address in %s", what);
+			else
+				seterr(ECorrupt, "overlapping ranges in %s", what);
+			return -1;
+		}
+		if(am[i].stop < am[i].start){
+			seterr(ECorrupt, "invalid range in %s", what);
+			return -1;
+		}
+		last = am[i].stop;
+	}
+	if(last > stop){
+		seterr(ECorrupt, "invalid ending address in %s", what);
+		return -1;
+	}
+	return 0;
+}
+
+int
+maparenas(AMap *am, Arena **arenas, int n, char *what)
+{
+	u32int i;
+
+	for(i = 0; i < n; i++){
+		arenas[i] = findarena(am[i].name);
+		if(arenas[i] == nil){
+			seterr(EAdmin, "can't find arena '%s' for '%s'\n", am[i].name, what);
+			return -1;
+		}
+	}
+	return 0;
+}
+
+int
+readarenamap(AMapN *amn, Part *part, u64int base, u32int size)
+{
+	IFile f;
+	u32int ok;
+
+	if(partifile(&f, part, base, size) < 0)
+		return -1;
+	ok = parseamap(&f, amn);
+	freeifile(&f);
+	return ok;
+}
+
+int
+wbarenamap(AMap *am, int n, Part *part, u64int base, u64int size)
+{
+	Fmt f;
+	ZBlock *b;
+
+	b = alloczblock(size, 1);
+	if(b == nil)
+		return -1;
+
+	fmtzbinit(&f, b);
+
+	if(outputamap(&f, am, n) < 0){
+		seterr(ECorrupt, "arena set size too small");
+		freezblock(b);
+		return -1;
+	}
+	if(writepart(part, base, b->data, size) < 0){
+		seterr(EAdmin, "can't write arena set: %r");
+		freezblock(b);
+		return -1;
+	}
+	freezblock(b);
+	return 0;
+}
+
+/*
+ * amap: n '\n' amapelem * n
+ * n: u32int
+ * amapelem: name '\t' astart '\t' asize '\n'
+ * astart, asize: u64int
+ */
+int
+parseamap(IFile *f, AMapN *amn)
+{
+	AMap *am;
+	u64int v64;
+	u32int v;
+	char *s, *flds[4];
+	int i, n;
+
+	/*
+	 * arenas
+	 */
+	if(ifileu32int(f, &v) < 0){
+		seterr(ECorrupt, "syntax error: bad number of elements in %s", f->name);
+		return -1;
+	}
+	n = v;
+	if(n > MaxAMap){
+		seterr(ECorrupt, "illegal number of elements in %s", f->name);
+		return -1;
+	}
+	am = MKNZ(AMap, n);
+	if(am == nil)
+		return -1;
+	for(i = 0; i < n; i++){
+		s = ifileline(f);
+		if(s == nil || getfields(s, flds, 4, 0, "\t") != 3)
+			return -1;
+		if(nameok(flds[0]) < 0)
+			return -1;
+		namecp(am[i].name, flds[0]);
+		if(stru64int(flds[1], &v64) < 0){
+			seterr(ECorrupt, "syntax error: bad arena base address in %s", f->name);
+			free(am);
+			return -1;
+		}
+		am[i].start = v64;
+		if(stru64int(flds[2], &v64) < 0){
+			seterr(ECorrupt, "syntax error: bad arena size in %s", f->name);
+			free(am);
+			return -1;
+		}
+		am[i].stop = v64;
+	}
+
+	amn->map = am;
+	amn->n = n;
+	return 0;
+}
+
+int
+outputamap(Fmt *f, AMap *am, int n)
+{
+	int i;
+
+	if(fmtprint(f, "%ud\n", n) < 0)
+		return -1;
+	for(i = 0; i < n; i++)
+		if(fmtprint(f, "%s\t%llud\t%llud\n", am[i].name, am[i].start, am[i].stop) < 0)
+			return -1;
+	return 0;
+}
diff --git a/src/cmd/venti/buildbuck.c b/src/cmd/venti/buildbuck.c
new file mode 100644
index 00000000..4232bb47
--- /dev/null
+++ b/src/cmd/venti/buildbuck.c
@@ -0,0 +1,112 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+struct IEStream
+{
+	Part	*part;
+	u64int	off;		/* read position within part */
+	u64int	n;		/* number of valid ientries left to read */
+	u32int	size;		/* allocated space in buffer */
+	u8int	*buf;
+	u8int	*pos;		/* current place in buffer */
+	u8int	*epos;		/* end of valid buffer contents */
+};
+
+IEStream*
+initiestream(Part *part, u64int off, u64int clumps, u32int size)
+{
+	IEStream *ies;
+
+//ZZZ out of memory?
+	ies = MKZ(IEStream);
+	ies->buf = MKN(u8int, size);
+	ies->epos = ies->buf;
+	ies->pos = ies->epos;
+	ies->off = off;
+	ies->n = clumps;
+	ies->size = size;
+	ies->part = part;
+	return ies;
+}
+
+void
+freeiestream(IEStream *ies)
+{
+	if(ies == nil)
+		return;
+	free(ies->buf);
+	free(ies);
+}
+
+static u8int*
+peekientry(IEStream *ies)
+{
+	u32int n, nn;
+
+	n = ies->epos - ies->pos;
+	if(n < IEntrySize){
+		memmove(ies->buf, ies->pos, n);
+		ies->epos = &ies->buf[n];
+		ies->pos = ies->buf;
+		nn = ies->size;
+		if(nn > ies->n * IEntrySize)
+			nn = ies->n * IEntrySize;
+		nn -= n;
+		if(nn == 0)
+			return nil;
+		if(readpart(ies->part, ies->off, ies->epos, nn) < 0){
+			seterr(EOk, "can't read sorted index entries: %r");
+			return nil;
+		}
+		ies->epos += nn;
+		ies->off += nn;
+	}
+	return ies->pos;
+}
+
+static u32int
+iebuck(Index *ix, u8int *b)
+{
+	return hashbits(b, 32) / ix->div;
+}
+
+u32int
+buildbucket(Index *ix, IEStream *ies, IBucket *ib)
+{
+	IEntry ie1, ie2;
+	u8int *b;
+	u32int buck;
+
+	buck = TWID32;
+	ib->n = 0;
+	ib->next = 0;
+	while(ies->n){
+		b = peekientry(ies);
+		if(b == nil)
+			return TWID32;
+//fprint(2, "b=%p ies->n=%lld ib.n=%d buck=%d score=%V\n", b, ies->n, ib->n, iebuck(ix, b), b);
+		if(ib->n == 0)
+			buck = iebuck(ix, b);
+		else{
+			if(buck != iebuck(ix, b))
+				break;
+			if(ientrycmp(&ib->data[(ib->n - 1)* IEntrySize], b) == 0){
+				/*
+				 * guess that the larger address is the correct one to use
+				 */
+				unpackientry(&ie1, &ib->data[(ib->n - 1)* IEntrySize]);
+				unpackientry(&ie2, b);
+				seterr(EOk, "duplicate index entry for score=%V type=%d\n", ie1.score, ie1.ia.type);
+				ib->n--;
+				if(ie1.ia.addr > ie2.ia.addr)
+					memmove(b, &ib->data[ib->n * IEntrySize], IEntrySize);
+			}
+		}
+		memmove(&ib->data[ib->n * IEntrySize], b, IEntrySize);
+		ib->n++;
+		ies->n--;
+		ies->pos += IEntrySize;
+	}
+	return buck;
+}
diff --git a/src/cmd/venti/buildindex.c b/src/cmd/venti/buildindex.c
new file mode 100644
index 00000000..952e75dd
--- /dev/null
+++ b/src/cmd/venti/buildindex.c
@@ -0,0 +1,145 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+static int
+writebucket(Index *ix, u32int buck, IBucket *ib, ZBlock *b)
+{
+	ISect *is;
+
+	is = findisect(ix, buck);
+	if(is == nil){
+		seterr(EAdmin, "bad math in writebucket");
+		return -1;
+	}
+	if(buck < is->start || buck >= is->stop)
+		seterr(EAdmin, "index write out of bounds: %d not in [%d,%d)\n",
+				buck, is->start, is->stop);
+	buck -= is->start;
+	qlock(&stats.lock);
+	stats.indexwrites++;
+	qunlock(&stats.lock);
+	packibucket(ib, b->data);
+	return writepart(is->part, is->blockbase + ((u64int)buck << is->blocklog), b->data, is->blocksize);
+}
+
+static int
+buildindex(Index *ix, Part *part, u64int off, u64int clumps, int zero)
+{
+	IEStream *ies;
+	IBucket ib, zib;
+	ZBlock *z, *b;
+	u32int next, buck;
+	int ok;
+	u64int found = 0;
+
+//ZZZ make buffer size configurable
+	b = alloczblock(ix->blocksize, 0);
+	z = alloczblock(ix->blocksize, 1);
+	ies = initiestream(part, off, clumps, 64*1024);
+	if(b == nil || z == nil || ies == nil){
+		ok = 0;
+		goto breakout;
+		return -1;
+	}
+	ok = 0;
+	next = 0;
+	ib.data = b->data + IBucketSize;
+	zib.data = z->data + IBucketSize;
+	zib.n = 0;
+	zib.next = 0;
+	for(;;){
+		buck = buildbucket(ix, ies, &ib);
+		found += ib.n;
+		if(zero){
+			for(; next != buck; next++){
+				if(next == ix->buckets){
+					if(buck != TWID32){
+						fprint(2, "bucket out of range\n");
+						ok = -1;
+					}
+					goto breakout;
+				}
+				if(writebucket(ix, next, &zib, z) < 0){
+					fprint(2, "can't write zero bucket to buck=%d: %r", next);
+					ok = -1;
+				}
+			}
+		}
+		if(buck >= ix->buckets){
+			if(buck == TWID32)
+				break;
+			fprint(2, "bucket out of range\n");
+			ok = -1;
+			goto breakout;
+		}
+		if(writebucket(ix, buck, &ib, b) < 0){
+			fprint(2, "bad bucket found=%lld: %r\n", found);
+			ok = -1;
+		}
+		next = buck + 1;
+	}
+breakout:;
+	fprint(2, "constructed index with %lld entries\n", found);
+	freeiestream(ies);
+	freezblock(z);
+	freezblock(b);
+	return ok;
+}
+
+void
+usage(void)
+{
+	fprint(2, "usage: buildindex [-Z] [-B blockcachesize] config tmppart\n");
+	threadexitsall(0);
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	Part *part;
+	u64int clumps, base;
+	u32int bcmem;
+	int zero;
+
+	zero = 1;
+	bcmem = 0;
+	ARGBEGIN{
+	case 'B':
+		bcmem = unittoull(ARGF());
+		break;
+	case 'Z':
+		zero = 0;
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	if(argc != 2)
+		usage();
+
+	if(initventi(argv[0]) < 0)
+		sysfatal("can't init venti: %r");
+
+	if(bcmem < maxblocksize * (mainindex->narenas + mainindex->nsects * 4 + 16))
+		bcmem = maxblocksize * (mainindex->narenas + mainindex->nsects * 4 + 16);
+	fprint(2, "initialize %d bytes of disk block cache\n", bcmem);
+	initdcache(bcmem);
+
+	fprint(2, "building a new index %s using %s for temporary storage\n", mainindex->name, argv[1]);
+
+	part = initpart(argv[1], 1);
+	if(part == nil)
+		sysfatal("can't initialize temporary partition: %r");
+
+	clumps = sortrawientries(mainindex, part, &base);
+	if(clumps == TWID64)
+		sysfatal("can't build sorted index: %r");
+	fprint(2, "found and sorted index entries for clumps=%lld at %lld\n", clumps, base);
+
+	if(buildindex(mainindex, part, base, clumps, zero) < 0)
+		sysfatal("can't build new index: %r");
+	
+	threadexitsall(0);
+}
diff --git a/src/cmd/venti/checkarenas.c b/src/cmd/venti/checkarenas.c
new file mode 100644
index 00000000..ae7c641a
--- /dev/null
+++ b/src/cmd/venti/checkarenas.c
@@ -0,0 +1,120 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+static int	verbose;
+
+static void
+checkarena(Arena *arena, int scan, int fix)
+{
+	Arena old;
+	int err, e;
+
+	if(verbose && arena->clumps)
+		printarena(2, arena);
+
+	old = *arena;
+
+	if(scan){
+		arena->used = 0;
+		arena->clumps = 0;
+		arena->cclumps = 0;
+		arena->uncsize = 0;
+	}
+
+	err = 0;
+	for(;;){
+		e = syncarena(arena, 1000, 0, fix);
+		err |= e;
+		if(!(e & SyncHeader))
+			break;
+		if(verbose && arena->clumps)
+			fprint(2, ".");
+	}
+	if(verbose && arena->clumps)
+		fprint(2, "\n");
+
+	err &= ~SyncHeader;
+	if(arena->used != old.used
+	|| arena->clumps != old.clumps
+	|| arena->cclumps != old.cclumps
+	|| arena->uncsize != old.uncsize){
+		fprint(2, "incorrect arena header fields\n");
+		printarena(2, arena);
+		err |= SyncHeader;
+	}
+
+	if(!err || !fix)
+		return;
+
+	fprint(2, "writing fixed arena header fields\n");
+	if(wbarena(arena) < 0)
+		fprint(2, "arena header write failed: %r\n");
+}
+
+void
+usage(void)
+{
+	fprint(2, "usage: checkarenas [-afv] file\n");
+	threadexitsall(0);
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	ArenaPart *ap;
+	Part *part;
+	char *file;
+	int i, fix, scan;
+
+	fmtinstall('V', vtscorefmt);
+
+	statsinit();
+
+	fix = 0;
+	scan = 0;
+	ARGBEGIN{
+	case 'f':
+		fix++;
+		break;
+	case 'a':
+		scan = 1;
+		break;
+	case 'v':
+		verbose++;
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	if(!fix)
+		readonly = 1;
+
+	if(argc != 1)
+		usage();
+
+	file = argv[0];
+
+	part = initpart(file, 0);
+	if(part == nil)
+		sysfatal("can't open partition %s: %r", file);
+
+	ap = initarenapart(part);
+	if(ap == nil)
+		sysfatal("can't initialize arena partition in %s: %r", file);
+
+	if(verbose > 1){
+		printarenapart(2, ap);
+		fprint(2, "\n");
+	}
+
+	initdcache(8 * MaxDiskBlock);
+
+	for(i = 0; i < ap->narenas; i++)
+		checkarena(ap->arenas[i], scan, fix);
+
+	if(verbose > 1)
+		printstats();
+	threadexitsall(0);
+}
diff --git a/src/cmd/venti/checkindex.c b/src/cmd/venti/checkindex.c
new file mode 100644
index 00000000..fa6f5efc
--- /dev/null
+++ b/src/cmd/venti/checkindex.c
@@ -0,0 +1,188 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+static int
+checkbucket(Index *ix, u32int buck, IBucket *ib)
+{
+	ISect *is;
+	DBlock *eb;
+	IBucket eib;
+	IEntry ie, eie;
+	int i, ei, ok, c;
+
+	is = findisect(ix, buck);
+	if(is == nil){
+		seterr(EAdmin, "bad math in checkbuckets");
+		return -1;
+	}
+	buck -= is->start;
+	eb = getdblock(is->part, is->blockbase + ((u64int)buck << is->blocklog), 1);
+	if(eb == nil)
+		return -1;
+	unpackibucket(&eib, eb->data);
+
+	ok = 0;
+	ei = 0;
+	for(i = 0; i < ib->n; i++){
+		while(ei < eib.n){
+			c = ientrycmp(&ib->data[i * IEntrySize], &eib.data[ei * IEntrySize]);
+			if(c == 0){
+				unpackientry(&ie, &ib->data[i * IEntrySize]);
+				unpackientry(&eie, &eib.data[ei * IEntrySize]);
+				if(iaddrcmp(&ie.ia, &eie.ia) != 0){
+					fprint(2, "bad entry in index for score=%V\n", &ib->data[i * IEntrySize]);
+					fprint(2, "\taddr=%lld type=%d size=%d blocks=%d\n",
+						ie.ia.addr, ie.ia.type, ie.ia.size, ie.ia.blocks);
+					fprint(2, "\taddr=%lld type=%d size=%d blocks=%d\n",
+						eie.ia.addr, eie.ia.type, eie.ia.size, eie.ia.blocks);
+				}
+				ei++;
+				goto cont;
+			}
+			if(c < 0)
+				break;
+if(1)
+			fprint(2, "spurious entry in index for score=%V type=%d\n",
+				&eib.data[ei * IEntrySize], eib.data[ei * IEntrySize + IEntryTypeOff]);
+			ei++;
+			ok = -1;
+		}
+		fprint(2, "missing entry in index for score=%V type=%d\n",
+			&ib->data[i * IEntrySize], ib->data[i * IEntrySize + IEntryTypeOff]);
+		ok = -1;
+	cont:;
+	}
+	for(; ei < eib.n; ei++){
+if(1)		fprint(2, "spurious entry in index for score=%V; found %d entries expected %d\n",
+			&eib.data[ei * IEntrySize], eib.n, ib->n);
+		ok = -1;
+		break;
+	}
+	putdblock(eb);
+	return ok;
+}
+
+int
+checkindex(Index *ix, Part *part, u64int off, u64int clumps, int zero)
+{
+	IEStream *ies;
+	IBucket ib, zib;
+	ZBlock *z, *b;
+	u32int next, buck;
+	int ok, bok;
+u64int found = 0;
+
+//ZZZ make buffer size configurable
+	b = alloczblock(ix->blocksize, 0);
+	z = alloczblock(ix->blocksize, 1);
+	ies = initiestream(part, off, clumps, 64*1024);
+	if(b == nil || z == nil || ies == nil){
+		ok = -1;
+		goto breakout;
+		return -1;
+	}
+	ok = 0;
+	next = 0;
+	ib.data = b->data;
+	zib.data = z->data;
+	zib.n = 0;
+	zib.next = 0;
+	for(;;){
+		buck = buildbucket(ix, ies, &ib);
+		found += ib.n;
+		if(zero){
+			for(; next != buck; next++){
+				if(next == ix->buckets){
+					if(buck != TWID32)
+						fprint(2, "bucket out of range\n");
+					goto breakout;
+				}
+				bok = checkbucket(ix, next, &zib);
+				if(bok < 0){
+					fprint(2, "bad bucket=%d found: %r\n", next);
+					ok = -1;
+				}
+			}
+		}
+		if(buck >= ix->buckets){
+			if(buck == TWID32)
+				break;
+			fprint(2, "bucket out of range\n");
+			ok = -1;
+			goto breakout;
+		}
+		bok = checkbucket(ix, buck, &ib);
+		if(bok < 0){
+			fprint(2, "bad bucket found=%lld: %r\n", found);
+			ok = -1;
+		}
+		next = buck + 1;
+	}
+breakout:;
+fprint(2, "found %lld entries in sorted list\n", found);
+	freeiestream(ies);
+	freezblock(z);
+	freezblock(b);
+	return ok;
+}
+
+void
+usage(void)
+{
+	fprint(2, "usage: checkindex [-f] [-B blockcachesize] config tmp\n");
+	threadexitsall(0);
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	Part *part;
+	u64int clumps, base;
+	u32int bcmem;
+	int fix, skipz;
+
+	fix = 0;
+	bcmem = 0;
+	skipz = 0;
+	ARGBEGIN{
+	case 'B':
+		bcmem = unittoull(ARGF());
+		break;
+	case 'f':
+		fix++;
+		break;
+	case 'Z':
+		skipz = 1;
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	if(!fix)
+		readonly = 1;
+
+	if(argc != 2)
+		usage();
+
+	if(initventi(argv[0]) < 0)
+		sysfatal("can't init venti: %r");
+
+	if(bcmem < maxblocksize * (mainindex->narenas + mainindex->nsects * 4 + 16))
+		bcmem = maxblocksize * (mainindex->narenas + mainindex->nsects * 4 + 16);
+	fprint(2, "initialize %d bytes of disk block cache\n", bcmem);
+	initdcache(bcmem);
+
+	part = initpart(argv[1], 1);
+	if(part == nil)
+		sysfatal("can't initialize temporary partition: %r");
+
+	clumps = sortrawientries(mainindex, part, &base);
+	if(clumps == TWID64)
+		sysfatal("can't build sorted index: %r");
+	fprint(2, "found and sorted index entries for clumps=%lld at %lld\n", clumps, base);
+	checkindex(mainindex, part, base, clumps, !skipz);
+	
+	threadexitsall(0);
+}
diff --git a/src/cmd/venti/clump.c b/src/cmd/venti/clump.c
new file mode 100644
index 00000000..272d7aec
--- /dev/null
+++ b/src/cmd/venti/clump.c
@@ -0,0 +1,200 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+#include "whack.h"
+
+/*
+ * writes a lump to disk
+ * returns the address in amap of the clump
+ */
+int
+storeclump(Index *ix, ZBlock *zb, u8int *sc, int type, u32int creator, IAddr *ia)
+{
+	ZBlock *cb;
+	Clump cl;
+	u64int a;
+	u8int bh[VtScoreSize];
+	int size, dsize;
+
+if(0)print("storeclump %08x %p\n", mainindex->arenas[0], &cl);
+	size = zb->len;
+	if(size > VtMaxLumpSize){
+		seterr(EStrange, "lump too large");
+		return -1;
+	}
+	if(vttypevalid(type) < 0){
+		seterr(EStrange, "invalid lump type");
+		return -1;
+	}
+
+	if(1){
+		scoremem(bh, zb->data, size);
+		if(scorecmp(sc, bh) != 0){
+			seterr(ECorrupt, "storing clump: corrupted; expected=%V got=%V, size=%d", sc, bh, size);
+			return -1;
+		}
+	}
+
+	cb = alloczblock(size + ClumpSize, 0);
+	if(cb == nil)
+		return -1;
+
+	cl.info.type = type;
+	cl.info.uncsize = size;
+	cl.creator = creator;
+	cl.time = now();
+	scorecp(cl.info.score, sc);
+
+if(0)print("whackblock %08x %p\n", mainindex->arenas[0], &cl);
+	dsize = whackblock(&cb->data[ClumpSize], zb->data, size);
+if(0)print("whackedblock %08x %p\n", mainindex->arenas[0], &cl);
+	if(dsize > 0 && dsize < size){
+		cl.encoding = ClumpECompress;
+	}else{
+		cl.encoding = ClumpENone;
+		dsize = size;
+		memmove(&cb->data[ClumpSize], zb->data, size);
+	}
+	cl.info.size = dsize;
+
+	a = writeiclump(ix, &cl, cb->data);
+
+	freezblock(cb);
+	if(a == 0)
+		return -1;
+
+	qlock(&stats.lock);
+	stats.clumpwrites++;
+	stats.clumpbwrites += size;
+	stats.clumpbcomp += dsize;
+	qunlock(&stats.lock);
+
+	ia->addr = a;
+	ia->type = type;
+	ia->size = size;
+	ia->blocks = (dsize + ClumpSize + (1 << ABlockLog) - 1) >> ABlockLog;
+
+	return 0;
+}
+
+u32int
+clumpmagic(Arena *arena, u64int aa)
+{
+	u8int buf[U32Size];
+
+	if(readarena(arena, aa, buf, U32Size) < 0)
+		return TWID32;
+	return unpackmagic(buf);
+}
+
+/*
+ * fetch a block based at addr.
+ * score is filled in with the block's score.
+ * blocks is roughly the length of the clump on disk;
+ * if zero, the length is unknown.
+ */
+ZBlock*
+loadclump(Arena *arena, u64int aa, int blocks, Clump *cl, u8int *score, int verify)
+{
+	Unwhack uw;
+	ZBlock *zb, *cb;
+	u8int bh[VtScoreSize], *buf;
+	u32int n;
+	int nunc;
+
+	qlock(&stats.lock);
+	stats.clumpreads++;
+	qunlock(&stats.lock);
+
+	if(blocks <= 0)
+		blocks = 1;
+
+	cb = alloczblock(blocks << ABlockLog, 0);
+	if(cb == nil)
+		return nil;
+	n = readarena(arena, aa, cb->data, blocks << ABlockLog);
+	if(n < ClumpSize){
+		if(n != 0)
+			seterr(ECorrupt, "loadclump read less than a header");
+		freezblock(cb);
+		return nil;
+	}
+	if(unpackclump(cl, cb->data) < 0){
+		freezblock(cb);
+		return nil;
+	}
+	n -= ClumpSize;
+	if(n < cl->info.size){
+		freezblock(cb);
+		n = cl->info.size;
+		cb = alloczblock(n, 0);
+		if(cb == nil)
+			return nil;
+		if(readarena(arena, aa + ClumpSize, cb->data, n) != n){
+			seterr(ECorrupt, "loadclump read too little data");
+			freezblock(cb);
+			return nil;
+		}
+		buf = cb->data;
+	}else
+		buf = cb->data + ClumpSize;
+
+	scorecp(score, cl->info.score);
+
+	zb = alloczblock(cl->info.uncsize, 0);
+	if(zb == nil){
+		freezblock(cb);
+		return nil;
+	}
+	switch(cl->encoding){
+	case ClumpECompress:
+		unwhackinit(&uw);
+		nunc = unwhack(&uw, zb->data, cl->info.uncsize, buf, cl->info.size);
+		if(nunc != cl->info.uncsize){
+			if(nunc < 0)
+				seterr(ECorrupt, "decompression failed: %s", uw.err);
+			else
+				seterr(ECorrupt, "decompression gave partial block: %d/%d\n", nunc, cl->info.uncsize);
+			freezblock(cb);
+			freezblock(zb);
+			return nil;
+		}
+		break;
+	case ClumpENone:
+		if(cl->info.size != cl->info.uncsize){
+			seterr(ECorrupt, "loading clump: bad uncompressed size for uncompressed block");
+			freezblock(cb);
+			freezblock(zb);
+			return nil;
+		}
+		memmove(zb->data, buf, cl->info.uncsize);
+		break;
+	default:
+		seterr(ECorrupt, "unknown encoding in loadlump");
+		freezblock(cb);
+		freezblock(zb);
+		return nil;
+	}
+	freezblock(cb);
+
+	if(verify){
+		scoremem(bh, zb->data, cl->info.uncsize);
+		if(scorecmp(cl->info.score, bh) != 0){
+			seterr(ECorrupt, "loading clump: corrupted; expected=%V got=%V", cl->info.score, bh);
+			freezblock(zb);
+			return nil;
+		}
+		if(vttypevalid(cl->info.type) < 0){
+			seterr(ECorrupt, "loading lump: invalid lump type %d", cl->info.type);
+			freezblock(zb);
+			return nil;
+		}
+	}
+
+	qlock(&stats.lock);
+	stats.clumpbreads += cl->info.size;
+	stats.clumpbuncomp += cl->info.uncsize;
+	qunlock(&stats.lock);
+
+	return zb;
+}
diff --git a/src/cmd/venti/clumpstats.c b/src/cmd/venti/clumpstats.c
new file mode 100644
index 00000000..5a448b67
--- /dev/null
+++ b/src/cmd/venti/clumpstats.c
@@ -0,0 +1,128 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+int	count[VtMaxLumpSize][VtMaxType];
+
+enum
+{
+	ClumpChunks	= 32*1024
+};
+
+static int
+readarenainfo(Arena *arena)
+{
+	ClumpInfo *ci, *cis;
+	u32int clump;
+	int i, n, ok;
+
+	if(arena->clumps)
+		fprint(2, "reading directory for arena=%s with %d entries\n", arena->name, arena->clumps);
+
+	cis = MKN(ClumpInfo, ClumpChunks);
+	ok = 0;
+	for(clump = 0; clump < arena->clumps; clump += n){
+		n = ClumpChunks;
+
+		if(n > arena->clumps - clump)
+			n = arena->clumps - clump;
+
+		if((i=readclumpinfos(arena, clump, cis, n)) != n){
+			seterr(EOk, "arena directory read failed %d not %d: %r", i, n);
+			ok = -1;
+			break;
+		}
+
+		for(i = 0; i < n; i++){
+			ci = &cis[i];
+			if(ci->type >= VtMaxType || ci->uncsize >= VtMaxLumpSize) {
+				fprint(2, "bad clump: %d: type = %d: size = %d\n", clump+i, ci->type, ci->uncsize);
+				continue;
+			}
+if(ci->uncsize == 422)
+print("%s: %d: %V\n", arena->name, clump+i, ci->score);
+			count[ci->uncsize][ci->type]++;
+		}
+	}
+	free(cis);
+	if(ok < 0)
+		return TWID32;
+	return clump;
+}
+
+static void
+clumpstats(Index *ix)
+{
+	int ok;
+	ulong clumps, n;
+	int i, j, t;
+
+	ok = 0;
+	clumps = 0;
+	for(i = 0; i < ix->narenas; i++){
+		n = readarenainfo(ix->arenas[i]);
+		if(n == TWID32){
+			ok = -1;
+			break;
+		}
+		clumps += n;
+	}
+
+	if(ok < 0)
+		return;
+
+	print("clumps = %ld\n", clumps);
+	for(i=0; i<VtMaxLumpSize; i++) {
+		t = 0;
+		for(j=0; j<VtMaxType; j++)
+			t += count[i][j];
+		if(t == 0)
+			continue;
+		print("%d\t%d", i, t);
+		for(j=0; j<VtMaxType; j++)
+			print("\t%d", count[i][j]);
+		print("\n");
+	}
+}
+
+
+void
+usage(void)
+{
+	fprint(2, "usage: clumpstats [-B blockcachesize] config\n");
+	threadexitsall(0);
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	u32int bcmem;
+
+	bcmem = 0;
+
+	ARGBEGIN{
+	case 'B':
+		bcmem = unittoull(ARGF());
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	readonly = 1;
+
+	if(argc != 1)
+		usage();
+
+	if(initventi(argv[0]) < 0)
+		sysfatal("can't init venti: %r");
+
+	if(bcmem < maxblocksize * (mainindex->narenas + mainindex->nsects * 4 + 16))
+		bcmem = maxblocksize * (mainindex->narenas + mainindex->nsects * 4 + 16);
+	fprint(2, "initialize %d bytes of disk block cache\n", bcmem);
+	initdcache(bcmem);
+
+	clumpstats(mainindex);
+	
+	threadexitsall(0);
+}
diff --git a/src/cmd/venti/config.c b/src/cmd/venti/config.c
new file mode 100644
index 00000000..cdcaad10
--- /dev/null
+++ b/src/cmd/venti/config.c
@@ -0,0 +1,144 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+Index			*mainindex;
+int			paranoid = 1;		/* should verify hashes on disk read */
+
+static ArenaPart	*configarenas(char *file);
+static ISect		*configisect(char *file);
+
+int
+initventi(char *file)
+{
+	Config conf;
+
+	fmtinstall('V', vtscorefmt);
+
+	statsinit();
+
+	if(file == nil){
+		seterr(EOk, "no configuration file");
+		return -1;
+	}
+	if(runconfig(file, &conf) < 0){
+		seterr(EOk, "can't initialize venti: %r");
+		return -1;
+	}
+	mainindex = initindex(conf.index, conf.sects, conf.nsects);
+	if(mainindex == nil)
+		return -1;
+	return 0;
+}
+
+/*
+ * configs	:
+ *		| configs config
+ * config	: "isect" filename
+ *		| "arenas" filename
+ *		| "index" name
+ *
+ * '#' and \n are comments
+ */
+enum
+{
+	MaxArgs	= 2
+};
+int
+runconfig(char *file, Config *config)
+{
+	ArenaPart **av;
+	ISect **sv;
+	IFile f;
+	char *s, *line, *flds[MaxArgs + 1];
+	int i, ok;
+
+	if(readifile(&f, file) < 0)
+		return -1;
+	config->index = nil;
+	config->naparts = 0;
+	config->aparts = nil;
+	config->nsects = 0;
+	config->sects = nil;
+	ok = -1;
+	line = nil;
+	for(;;){
+		s = ifileline(&f);
+		if(s == nil){
+			ok = 0;
+			break;
+		}
+		line = estrdup(s);
+		i = getfields(s, flds, MaxArgs + 1, 1, " \t\r");
+		if(i == 2 && strcmp(flds[0], "isect") == 0){
+			sv = MKN(ISect*, config->nsects + 1);
+			for(i = 0; i < config->nsects; i++)
+				sv[i] = config->sects[i];
+			free(config->sects);
+			config->sects = sv;
+			config->sects[config->nsects] = configisect(flds[1]);
+			if(config->sects[config->nsects] == nil)
+				break;
+			config->nsects++;
+		}else if(i == 2 && strcmp(flds[0], "arenas") == 0){
+			av = MKN(ArenaPart*, config->naparts + 1);
+			for(i = 0; i < config->naparts; i++)
+				av[i] = config->aparts[i];
+			free(config->aparts);
+			config->aparts = av;
+			config->aparts[config->naparts] = configarenas(flds[1]);
+			if(config->aparts[config->naparts] == nil)
+				break;
+			config->naparts++;
+		}else if(i == 2 && strcmp(flds[0], "index") == 0){
+			if(nameok(flds[1]) < 0){
+				seterr(EAdmin, "illegal index name %s in config file %s", flds[1], config);
+				break;
+			}
+			if(config->index != nil){
+				seterr(EAdmin, "duplicate indices in config file %s", config);
+				break;
+			}
+			config->index = estrdup(flds[1]);
+		}else{
+			seterr(EAdmin, "illegal line '%s' in configuration file %s", line, config);
+			break;
+		}
+		free(line);
+		line = nil;
+	}
+	free(line);
+	freeifile(&f);
+	if(ok < 0){
+		free(config->sects);
+		config->sects = nil;
+		free(config->aparts);
+		config->aparts = nil;
+	}
+	return ok;
+}
+
+static ISect*
+configisect(char *file)
+{
+	Part *part;
+
+	fprint(2, "configure index section in %s\n", file);
+
+	part = initpart(file, 0);
+	if(part == nil)
+		return nil;
+	return initisect(part);
+}
+
+static ArenaPart*
+configarenas(char *file)
+{
+	Part *part;
+
+	fprint(2, "configure arenas in %s\n", file);
+	part = initpart(file, 0);
+	if(part == nil)
+		return nil;
+	return initarenapart(part);
+}
diff --git a/src/cmd/venti/conv.c b/src/cmd/venti/conv.c
new file mode 100644
index 00000000..ae89baa7
--- /dev/null
+++ b/src/cmd/venti/conv.c
@@ -0,0 +1,500 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+/*
+ * disk structure conversion routines
+ */
+#define	U8GET(p)	((p)[0])
+#define	U16GET(p)	(((p)[0]<<8)|(p)[1])
+#define	U32GET(p)	((u32int)(((p)[0]<<24)|((p)[1]<<16)|((p)[2]<<8)|(p)[3]))
+#define	U64GET(p)	(((u64int)U32GET(p)<<32)|(u64int)U32GET((p)+4))
+
+#define	U8PUT(p,v)	(p)[0]=(v)&0xFF
+#define	U16PUT(p,v)	(p)[0]=((v)>>8)&0xFF;(p)[1]=(v)&0xFF
+#define	U32PUT(p,v)	(p)[0]=((v)>>24)&0xFF;(p)[1]=((v)>>16)&0xFF;(p)[2]=((v)>>8)&0xFF;(p)[3]=(v)&0xFF
+#define	U64PUT(p,v,t32)	t32=(v)>>32;U32PUT(p,t32);t32=(v);U32PUT((p)+4,t32)
+
+static struct {
+	u32int m;
+	char *s;
+} magics[] = {
+	ArenaPartMagic, "ArenaPartMagic",
+	ArenaHeadMagic, "ArenaHeadMagic",
+	ArenaMagic, "ArenaMagic",
+	ISectMagic, "ISectMagic",
+};
+
+static char*
+fmtmagic(char *s, u32int m)
+{
+	int i;
+
+	for(i=0; i<nelem(magics); i++)
+		if(magics[i].m == m)
+			return magics[i].s;
+	sprint(s, "0x%08lux", m);
+	return s;
+}
+
+u32int
+unpackmagic(u8int *buf)
+{
+	return U32GET(buf);
+}
+
+void
+packmagic(u32int magic, u8int *buf)
+{
+	U32PUT(buf, magic);
+}
+
+int
+unpackarenapart(ArenaPart *ap, u8int *buf)
+{
+	u8int *p;
+	u32int m;
+	char fbuf[20];
+
+	p = buf;
+
+	m = U32GET(p);
+	if(m != ArenaPartMagic){
+		seterr(ECorrupt, "arena set has wrong magic number: %s expected ArenaPartMagic (%lux)", fmtmagic(fbuf, m), ArenaPartMagic);
+		return -1;
+	}
+	p += U32Size;
+	ap->version = U32GET(p);
+	p += U32Size;
+	ap->blocksize = U32GET(p);
+	p += U32Size;
+	ap->arenabase = U32GET(p);
+	p += U32Size;
+
+	if(buf + ArenaPartSize != p)
+		sysfatal("unpackarenapart unpacked wrong amount");
+
+	return 0;
+}
+
+int
+packarenapart(ArenaPart *ap, u8int *buf)
+{
+	u8int *p;
+
+	p = buf;
+
+	U32PUT(p, ArenaPartMagic);
+	p += U32Size;
+	U32PUT(p, ap->version);
+	p += U32Size;
+	U32PUT(p, ap->blocksize);
+	p += U32Size;
+	U32PUT(p, ap->arenabase);
+	p += U32Size;
+
+	if(buf + ArenaPartSize != p)
+		sysfatal("packarenapart packed wrong amount");
+
+	return 0;
+}
+
+int
+unpackarena(Arena *arena, u8int *buf)
+{
+	u8int *p;
+	u32int m;
+	char fbuf[20];
+
+	p = buf;
+
+	m = U32GET(p);
+	if(m != ArenaMagic){
+		seterr(ECorrupt, "arena has wrong magic number: %s expected ArenaMagic (%lux)", fmtmagic(fbuf, m), m, ArenaMagic);
+		return -1;
+	}
+	p += U32Size;
+	arena->version = U32GET(p);
+	p += U32Size;
+	namecp(arena->name, (char*)p);
+	p += ANameSize;
+	arena->clumps = U32GET(p);
+	p += U32Size;
+	arena->cclumps = U32GET(p);
+	p += U32Size;
+	arena->ctime = U32GET(p);
+	p += U32Size;
+	arena->wtime = U32GET(p);
+	p += U32Size;
+	arena->used = U64GET(p);
+	p += U64Size;
+	arena->uncsize = U64GET(p);
+	p += U64Size;
+	arena->sealed = U8GET(p);
+	p += U8Size;
+
+	if(buf + ArenaSize != p)
+		sysfatal("unpackarena unpacked wrong amount");
+
+	return 0;
+}
+
+int
+packarena(Arena *arena, u8int *buf)
+{
+	u8int *p;
+	u32int t32;
+
+	p = buf;
+
+	U32PUT(p, ArenaMagic);
+	p += U32Size;
+	U32PUT(p, arena->version);
+	p += U32Size;
+	namecp((char*)p, arena->name);
+	p += ANameSize;
+	U32PUT(p, arena->clumps);
+	p += U32Size;
+	U32PUT(p, arena->cclumps);
+	p += U32Size;
+	U32PUT(p, arena->ctime);
+	p += U32Size;
+	U32PUT(p, arena->wtime);
+	p += U32Size;
+	U64PUT(p, arena->used, t32);
+	p += U64Size;
+	U64PUT(p, arena->uncsize, t32);
+	p += U64Size;
+	U8PUT(p, arena->sealed);
+	p += U8Size;
+
+	if(buf + ArenaSize != p)
+		sysfatal("packarena packed wrong amount");
+
+	return 0;
+}
+
+int
+unpackarenahead(ArenaHead *head, u8int *buf)
+{
+	u8int *p;
+	u32int m;
+	char fbuf[20];
+
+	p = buf;
+
+	m = U32GET(p);
+	if(m != ArenaHeadMagic){
+		seterr(ECorrupt, "arena has wrong magic number: %s expected ArenaHeadMagic (%lux)", 
+			fmtmagic(fbuf, m), ArenaHeadMagic);
+		return -1;
+	}
+	p += U32Size;
+	head->version = U32GET(p);
+	p += U32Size;
+	namecp(head->name, (char*)p);
+	p += ANameSize;
+	head->blocksize = U32GET(p);
+	p += U32Size;
+	head->size = U64GET(p);
+	p += U64Size;
+
+	if(buf + ArenaHeadSize != p)
+		sysfatal("unpackarenahead unpacked wrong amount");
+
+	return 0;
+}
+
+int
+packarenahead(ArenaHead *head, u8int *buf)
+{
+	u8int *p;
+	u32int t32;
+
+	p = buf;
+
+	U32PUT(p, ArenaHeadMagic);
+	p += U32Size;
+	U32PUT(p, head->version);
+	p += U32Size;
+	namecp((char*)p, head->name);
+	p += ANameSize;
+	U32PUT(p, head->blocksize);
+	p += U32Size;
+	U64PUT(p, head->size, t32);
+	p += U64Size;
+
+	if(buf + ArenaHeadSize != p)
+		sysfatal("packarenahead packed wrong amount");
+
+	return 0;
+}
+
+static int
+checkclump(Clump *w)
+{
+	if(w->encoding == ClumpENone){
+		if(w->info.size != w->info.uncsize){
+			seterr(ECorrupt, "uncompressed wad size mismatch");
+			return -1;
+		}
+	}else if(w->encoding == ClumpECompress){
+		if(w->info.size >= w->info.uncsize){
+			seterr(ECorrupt, "compressed lump has inconsistent block sizes %d %d", w->info.size, w->info.uncsize);
+			return -1;
+		}
+	}else{
+		seterr(ECorrupt, "clump has illegal encoding");
+		return -1;
+	}
+
+	return 0;
+}
+
+int
+unpackclump(Clump *c, u8int *buf)
+{
+	u8int *p;
+	u32int magic;
+
+	p = buf;
+	magic = U32GET(p);
+	if(magic != ClumpMagic){
+		seterr(ECorrupt, "clump has bad magic number=%#8.8ux", magic);
+		return -1;
+	}
+	p += U32Size;
+
+	c->info.type = vtfromdisktype(U8GET(p));
+	p += U8Size;
+	c->info.size = U16GET(p);
+	p += U16Size;
+	c->info.uncsize = U16GET(p);
+	p += U16Size;
+	scorecp(c->info.score, p);
+	p += VtScoreSize;
+
+	c->encoding = U8GET(p);
+	p += U8Size;
+	c->creator = U32GET(p);
+	p += U32Size;
+	c->time = U32GET(p);
+	p += U32Size;
+
+	if(buf + ClumpSize != p)
+		sysfatal("unpackclump unpacked wrong amount");
+
+	return checkclump(c);
+}
+
+int
+packclump(Clump *c, u8int *buf)
+{
+	u8int *p;
+
+	p = buf;
+	U32PUT(p, ClumpMagic);
+	p += U32Size;
+
+	U8PUT(p, vttodisktype(c->info.type));
+	p += U8Size;
+	U16PUT(p, c->info.size);
+	p += U16Size;
+	U16PUT(p, c->info.uncsize);
+	p += U16Size;
+	scorecp(p, c->info.score);
+	p += VtScoreSize;
+
+	U8PUT(p, c->encoding);
+	p += U8Size;
+	U32PUT(p, c->creator);
+	p += U32Size;
+	U32PUT(p, c->time);
+	p += U32Size;
+
+	if(buf + ClumpSize != p)
+		sysfatal("packclump packed wrong amount");
+
+	return checkclump(c);
+}
+
+void
+unpackclumpinfo(ClumpInfo *ci, u8int *buf)
+{
+	u8int *p;
+
+	p = buf;
+	ci->type = vtfromdisktype(U8GET(p));
+	p += U8Size;
+	ci->size = U16GET(p);
+	p += U16Size;
+	ci->uncsize = U16GET(p);
+	p += U16Size;
+	scorecp(ci->score, p);
+	p += VtScoreSize;
+
+	if(buf + ClumpInfoSize != p)
+		sysfatal("unpackclumpinfo unpacked wrong amount");
+}
+
+void
+packclumpinfo(ClumpInfo *ci, u8int *buf)
+{
+	u8int *p;
+
+	p = buf;
+	U8PUT(p, vttodisktype(ci->type));
+	p += U8Size;
+	U16PUT(p, ci->size);
+	p += U16Size;
+	U16PUT(p, ci->uncsize);
+	p += U16Size;
+	scorecp(p, ci->score);
+	p += VtScoreSize;
+
+	if(buf + ClumpInfoSize != p)
+		sysfatal("packclumpinfo packed wrong amount");
+}
+
+int
+unpackisect(ISect *is, u8int *buf)
+{
+	u8int *p;
+	u32int m;
+	char fbuf[20];
+
+	p = buf;
+
+
+	m = U32GET(p);
+	if(m != ISectMagic){
+		seterr(ECorrupt, "index section has wrong magic number: %s expected ISectMagic (%lux)",
+			fmtmagic(fbuf, m), ISectMagic);
+		return -1;
+	}
+	p += U32Size;
+	is->version = U32GET(p);
+	p += U32Size;
+	namecp(is->name, (char*)p);
+	p += ANameSize;
+	namecp(is->index, (char*)p);
+	p += ANameSize;
+	is->blocksize = U32GET(p);
+	p += U32Size;
+	is->blockbase = U32GET(p);
+	p += U32Size;
+	is->blocks = U32GET(p);
+	p += U32Size;
+	is->start = U32GET(p);
+	p += U32Size;
+	is->stop = U32GET(p);
+	p += U32Size;
+
+	if(buf + ISectSize != p)
+		sysfatal("unpackisect unpacked wrong amount");
+
+	return 0;
+}
+
+int
+packisect(ISect *is, u8int *buf)
+{
+	u8int *p;
+
+	p = buf;
+
+	U32PUT(p, ISectMagic);
+	p += U32Size;
+	U32PUT(p, is->version);
+	p += U32Size;
+	namecp((char*)p, is->name);
+	p += ANameSize;
+	namecp((char*)p, is->index);
+	p += ANameSize;
+	U32PUT(p, is->blocksize);
+	p += U32Size;
+	U32PUT(p, is->blockbase);
+	p += U32Size;
+	U32PUT(p, is->blocks);
+	p += U32Size;
+	U32PUT(p, is->start);
+	p += U32Size;
+	U32PUT(p, is->stop);
+	p += U32Size;
+
+	if(buf + ISectSize != p)
+		sysfatal("packisect packed wrong amount");
+
+	return 0;
+}
+
+void
+unpackientry(IEntry *ie, u8int *buf)
+{
+	u8int *p;
+
+	p = buf;
+
+	scorecp(ie->score, p);
+	p += VtScoreSize;
+	ie->wtime = U32GET(p);
+	p += U32Size;
+	ie->train = U16GET(p);
+	p += U16Size;
+	ie->ia.addr = U64GET(p);
+if(ie->ia.addr>>56) print("%.8H => %llux\n", p, ie->ia.addr);
+	p += U64Size;
+	ie->ia.size = U16GET(p);
+	p += U16Size;
+	if(p - buf != IEntryTypeOff)
+		sysfatal("unpackientry bad IEntryTypeOff amount");
+	ie->ia.type = vtfromdisktype(U8GET(p));
+	p += U8Size;
+	ie->ia.blocks = U8GET(p);
+	p += U8Size;
+
+	if(p - buf != IEntrySize)
+		sysfatal("unpackientry unpacked wrong amount");
+}
+
+void
+packientry(IEntry *ie, u8int *buf)
+{
+	u32int t32;
+	u8int *p;
+
+	p = buf;
+
+	scorecp(p, ie->score);
+	p += VtScoreSize;
+	U32PUT(p, ie->wtime);
+	p += U32Size;
+	U16PUT(p, ie->train);
+	p += U16Size;
+	U64PUT(p, ie->ia.addr, t32);
+	p += U64Size;
+	U16PUT(p, ie->ia.size);
+	p += U16Size;
+	U8PUT(p, vttodisktype(ie->ia.type));
+	p += U8Size;
+	U8PUT(p, ie->ia.blocks);
+	p += U8Size;
+
+	if(p - buf != IEntrySize)
+		sysfatal("packientry packed wrong amount");
+}
+
+void
+unpackibucket(IBucket *b, u8int *buf)
+{
+	b->n = U16GET(buf);
+	b->next = U32GET(&buf[U16Size]);
+	b->data = buf + IBucketSize;
+}
+
+void
+packibucket(IBucket *b, u8int *buf)
+{
+	U16PUT(buf, b->n);
+	U32PUT(&buf[U16Size], b->next);
+}
diff --git a/src/cmd/venti/copy.c b/src/cmd/venti/copy.c
new file mode 100644
index 00000000..8b5bb84d
--- /dev/null
+++ b/src/cmd/venti/copy.c
@@ -0,0 +1,169 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+int fast;
+
+VtConn *zsrc, *zdst;
+
+void
+usage(void)
+{
+	fprint(2, "usage: copy src-host dst-host score [type]\n");
+	threadexitsall("usage");
+}
+
+int
+parsescore(uchar *score, char *buf, int n)
+{
+	int i, c;
+
+	memset(score, 0, VtScoreSize);
+
+	if(n < VtScoreSize*2)
+		return -1;
+	for(i=0; i<VtScoreSize*2; i++) {
+		if(buf[i] >= '0' && buf[i] <= '9')
+			c = buf[i] - '0';
+		else if(buf[i] >= 'a' && buf[i] <= 'f')
+			c = buf[i] - 'a' + 10;
+		else if(buf[i] >= 'A' && buf[i] <= 'F')
+			c = buf[i] - 'A' + 10;
+		else {
+			return -1;
+		}
+
+		if((i & 1) == 0)
+			c <<= 4;
+	
+		score[i>>1] |= c;
+	}
+	return 0;
+}
+
+void
+walk(uchar score[VtScoreSize], uint type, int base)
+{
+	int i, n, sub;
+	uchar *buf;
+	VtEntry e;
+	VtRoot root;
+
+	if(memcmp(score, vtzeroscore, VtScoreSize) == 0)
+		return;
+
+	buf = vtmallocz(VtMaxLumpSize);
+	if(fast && vtread(zdst, score, type, buf, VtMaxLumpSize) >= 0){
+		fprint(2, "skip %V\n", score);
+		free(buf);
+		return;
+	}
+
+	n = vtread(zsrc, score, type, buf, VtMaxLumpSize);
+	if(n < 0){
+		fprint(2, "warning: could not read block %V %d: %r", score, type);
+		return;
+	}
+
+	switch(type){
+	case VtRootType:
+		if(vtrootunpack(&root, buf) < 0){
+			fprint(2, "warning: could not unpack root in %V %d\n", score, type);
+			break;
+		}
+		walk(root.score, VtDirType, 0);
+		walk(root.prev, VtRootType, 0);
+		break;
+
+	case VtDirType:
+		for(i=0; i<n/VtEntrySize; i++){
+			if(vtentryunpack(&e, buf, i) < 0){
+				fprint(2, "warning: could not unpack entry #%d in %V %d\n", i, score, type);
+				continue;
+			}
+			if(!(e.flags & VtEntryActive))
+				continue;
+			if(e.flags&VtEntryDir)
+				base = VtDirType;
+			else
+				base = VtDataType;
+			sub = base | ((e.flags&VtEntryDepthMask)>>VtEntryDepthShift);
+			walk(e.score, sub, base);
+		}
+		break;
+
+	case VtDataType:
+		break;
+
+	default:	/* pointers */
+		for(i=0; i<n; i+=VtScoreSize)
+			if(memcmp(buf+i, vtzeroscore, VtScoreSize) != 0)
+				walk(buf+i, type-1, base);
+		break;
+	}
+
+	if(vtwrite(zdst, score, type, buf, n) < 0)
+		fprint(2, "warning: could not write block %V %d: %r", score, type);
+	free(buf);
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	int type, n;
+	uchar score[VtScoreSize];
+	uchar *buf;
+
+	ARGBEGIN{
+	case 'f':
+		fast = 1;
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	if(argc != 3 && argc != 4)
+		usage();
+
+	fmtinstall('V', vtscorefmt);
+
+	if(parsescore(score, argv[2], strlen(argv[2]) < 0))
+		sysfatal("could not parse score: %r");
+
+	buf = vtmallocz(VtMaxLumpSize);
+
+	zsrc = vtdial(argv[0]);
+	if(zsrc == nil)
+		sysfatal("could not dial src server: %r");
+	if(vtconnect(zsrc) < 0)
+		sysfatal("vtconnect src: %r");
+
+	zdst = vtdial(argv[1]);
+	if(zdst == nil)
+		sysfatal("could not dial dst server: %r");
+	if(vtconnect(zdst) < 0)
+		sysfatal("vtconnect dst: %r");
+
+	if(argc == 4){
+		type = atoi(argv[3]);
+		n = vtread(zsrc, score, type, buf, VtMaxLumpSize);
+		if(n < 0)
+			sysfatal("could not read block: %r");
+	}else{
+		for(type=0; type<VtMaxType; type++){
+			n = vtread(zsrc, score, type, buf, VtMaxLumpSize);
+			if(n >= 0)
+				break;
+		}
+		if(type == VtMaxType)
+			sysfatal("could not find block %V of any type", score);
+	}
+
+	walk(score, type, VtDirType);
+
+	if(vtsync(zdst) < 0)
+		sysfatal("could not sync dst server: %r");
+
+	threadexitsall(0);
+}
diff --git a/src/cmd/venti/dat.h b/src/cmd/venti/dat.h
new file mode 100644
index 00000000..b9f395c8
--- /dev/null
+++ b/src/cmd/venti/dat.h
@@ -0,0 +1,497 @@
+typedef struct Config		Config;
+typedef struct AMap		AMap;
+typedef struct AMapN		AMapN;
+typedef struct Arena		Arena;
+typedef struct ArenaHead	ArenaHead;
+typedef struct ArenaPart	ArenaPart;
+typedef struct CIBlock		CIBlock;
+typedef struct Clump		Clump;
+typedef struct ClumpInfo	ClumpInfo;
+typedef struct IAddr		IAddr;
+typedef struct IBucket		IBucket;
+typedef struct ICache		ICache;
+typedef struct IEStream		IEStream;
+typedef struct IEntry		IEntry;
+typedef struct IFile		IFile;
+typedef struct ISect		ISect;
+typedef struct Index		Index;
+typedef struct Lump		Lump;
+typedef struct DBlock		DBlock;
+typedef struct Part		Part;
+typedef struct Stats		Stats;
+typedef struct ZBlock		ZBlock;
+
+#define TWID32	((u32int)~(u32int)0)
+#define TWID64	((u64int)~(u64int)0)
+#define	TWID8	((u8int)~(u8int)0)
+
+enum
+{
+	ABlockLog		= 9,		/* log2(512), the quantum for reading arenas */
+	ANameSize		= 64,
+	MaxDiskBlock		= 64*1024,	/* max. allowed size for a disk block */
+	MaxIoSize		= 64*1024,	/* max. allowed size for a disk io operation */
+	PartBlank		= 256*1024,	/* untouched section at beginning of partition */
+	HeadSize		= 512,		/* size of a header after PartBlank */
+	MinArenaSize		= 1*1024*1024,	/* smallest reasonable arena size */
+	IndexBase		= 1024*1024,	/* initial address to use in an index */
+	MaxIo			= 64*1024,	/* max size of a single read or write operation */
+	ICacheBits		= 16,		/* default bits for indexing icache */
+	ICacheDepth		= 4,		/* default depth of an icache hash chain */
+	MaxAMap			= 2*1024,	/* max. allowed arenas in an address mapping; must be < 32*1024 */
+
+	/*
+	 * return codes from syncarena
+	 */
+	SyncDataErr	= 1 << 0,		/* problem reading the clump data */
+	SyncCIErr	= 1 << 1,		/* found erroneous clump directory entries */
+	SyncCIZero	= 1 << 2,		/* found unwritten clump directory entries */
+	SyncFixErr	= 1 << 3,		/* error writing fixed data */
+	SyncHeader	= 1 << 4,		/* altered header fields */
+
+	/*
+	 * error severity
+	 */
+	EOk			= 0,		/* error expected in normal operation */
+	EStrange,				/* strange error that should be logged */
+	ECorrupt,				/* corrupted data found in arenas */
+	EICorrupt,				/* corrupted data found in index */
+	EAdmin,					/* should be brought to administrators' attention */
+	ECrash,					/* really bad internal error */
+	EBug,					/* a limitation which should be fixed */
+	EInconsist,				/* inconsistencies between index and arena */
+	EMax,
+
+	/*
+	 * internal disk formats for the venti archival storage system
+	 */
+	/*
+	 * magic numbers on disk
+	 */
+	ClumpMagic		= 0xd15cb10c,	/* clump header */
+	ClumpFreeMagic		= 0,		/* free clump; terminates active clump log */
+
+	ArenaPartMagic		= 0xa9e4a5e7,	/* arena partition header */
+	ArenaMagic		= 0xf2a14ead,	/* arena trailer */
+	ArenaHeadMagic		= 0xd15c4ead,	/* arena header */
+
+	ISectMagic		= 0xd15c5ec7,	/* index header */
+
+	ArenaPartVersion	= 3,
+	ArenaVersion		= 4,
+	IndexVersion		= 1,
+	ISectVersion		= 1,
+
+	/*
+	 * encodings of clumps on disk
+	 */
+	ClumpEErr		= 0,		/* can't happen */
+	ClumpENone,				/* plain */
+	ClumpECompress,				/* compressed */
+	ClumpEMax,
+
+	/*
+	 * marker for corrupted data on disk
+	 */
+	VtTypeCorrupt		= VtMaxType,
+
+	/*
+	 * sizes in bytes on disk
+	 */
+	U8Size			= 1,
+	U16Size			= 2,
+	U32Size			= 4,
+	U64Size			= 8,
+
+	ArenaPartSize		= 4 * U32Size,
+	ArenaSize		= 2 * U64Size + 6 * U32Size + ANameSize + U8Size,
+	ArenaHeadSize		= U64Size + 3 * U32Size + ANameSize,
+	ISectSize		= 7 * U32Size + 2 * ANameSize,
+	ClumpInfoSize		= U8Size + 2 * U16Size + VtScoreSize,
+	ClumpSize		= ClumpInfoSize + U8Size + 3 * U32Size,
+	IBucketSize		= U32Size + U16Size,
+	IEntrySize		= U64Size + U32Size + 2*U16Size + 2*U8Size + VtScoreSize,
+	IEntryTypeOff		= VtScoreSize + U64Size + U32Size + 2 * U16Size,
+
+	MaxClumpBlocks		=  (VtMaxLumpSize + ClumpSize + (1 << ABlockLog) - 1) >> ABlockLog,
+
+	VentiZZZZZZZZ
+};
+
+/*
+ * results of parsing and initializing a config file
+ */
+struct Config
+{
+	char		*index;			/* name of the index to initialize */
+	int		naparts;		/* arena partitions initialized */
+	ArenaPart	**aparts;
+	int		nsects;			/* index sections initialized */
+	ISect		**sects;
+};
+
+/*
+ * a Part is the low level interface to files or disks.
+ * there are two main types of partitions
+ *	arena paritions, which some number of arenas, each in a sub-partition.
+ *	index partition, which only have one subpartition.
+ */
+struct Part
+{
+	int		fd;			/* rock for accessing the disk */
+	u64int		size;			/* size of the partiton */
+	u32int		blocksize;		/* block size for reads and writes */
+	char		*name;
+};
+
+/*
+ * a cached block from the partition
+ * yuck -- most of this is internal structure for the cache
+ * all other routines should only use data
+ */
+struct DBlock
+{
+	u8int	*data;
+
+	Part	*part;			/* partition in which cached */
+	u64int	addr;			/* base address on the partition */
+	u16int	size;			/* amount of data available, not amount allocated; should go away */
+	DBlock	*next;			/* doubly linked hash chains */
+	DBlock	*prev;
+	u32int	heap;			/* index in heap table */
+	u32int	used;			/* last reference times */
+	u32int	used2;
+	u32int	ref;			/* reference count */
+	QLock	lock;			/* for access to data only */
+};
+
+/*
+ * a cached block from the partition
+ * yuck -- most of this is internal structure for the cache
+ * all other routines should only use data
+ * double yuck -- this is mostly the same as a DBlock
+ */
+struct Lump
+{
+	Packet	*data;
+
+	Part	*part;			/* partition in which cached */
+	u8int	score[VtScoreSize];	/* score of packet */
+	u8int	type;			/* type of packet */
+	u16int	size;			/* amount of data allocated to hold packet */
+	Lump	*next;			/* doubly linked hash chains */
+	Lump	*prev;
+	u32int	heap;			/* index in heap table */
+	u32int	used;			/* last reference times */
+	u32int	used2;
+	u32int	ref;			/* reference count */
+	QLock	lock;			/* for access to data only */
+};
+
+/*
+ * mapping between names and address ranges
+ */
+struct AMap
+{
+	u64int		start;
+	u64int		stop;
+	char		name[ANameSize];
+};
+
+/*
+ * an AMap along with a length
+ */
+struct AMapN
+{
+	int		n;
+	AMap		*map;
+};
+
+/*
+ * an ArenaPart is a partition made up of Arenas
+ * it exists because most os's don't support many partitions,
+ * and we want to have many different Arenas
+ */
+struct ArenaPart
+{
+	Part		*part;
+	u64int		size;			/* size of underlying partition, rounded down to blocks */
+	Arena		**arenas;
+	u32int		tabbase;		/* base address of arena table on disk */
+	u32int		tabsize;		/* max. bytes in arena table */
+
+	/*
+	 * fields stored on disk
+	 */
+	u32int		version;
+	u32int		blocksize;		/* "optimal" block size for reads and writes */
+	u32int		arenabase;		/* base address of first arena */
+
+	/*
+	 * stored in the arena mapping table on disk
+	 */
+	AMap		*map;
+	int		narenas;
+};
+
+/*
+ * info about one block in the clump info cache
+ */
+struct CIBlock
+{
+	u32int		block;			/* blocks in the directory */
+	int		offset;			/* offsets of one clump in the data */
+	DBlock		*data;
+};
+
+/*
+ * an Arena is a log of Clumps, preceeded by an ArenaHeader,
+ * and followed by a Arena, each in one disk block.
+ * struct on disk is not always up to date, but should be self-consistent.
+ * to sync after reboot, follow clumps starting at used until ClumpFreeMagic if found.
+ * <struct name="Arena" type="Arena *">
+ *	<field name="name" val="s->name" type="AName"/>
+ *	<field name="version" val="s->version" type="U32int"/>
+ *	<field name="partition" val="s->part->name" type="AName"/>
+ *	<field name="blocksize" val="s->blocksize" type="U32int"/>
+ *	<field name="start" val="s->base" type="U64int"/>
+ *	<field name="stop" val="s->base+2*s->blocksize" type="U64int"/>
+ *	<field name="created" val="s->ctime" type="U32int"/>
+ *	<field name="modified" val="s->wtime" type="U32int"/>
+ *	<field name="sealed" val="s->sealed" type="Sealed"/>
+ *	<field name="score" val="s->score" type="Score"/>
+ *	<field name="clumps" val="s->clumps" type="U32int"/>
+ *	<field name="compressedclumps" val="s->cclumps" type="U32int"/>
+ *	<field name="data" val="s->uncsize" type="U64int"/>
+ *	<field name="compresseddata" val="s->used - s->clumps * ClumpSize" type="U64int"/>
+ *	<field name="storage" val="s->used + s->clumps * ClumpInfoSize" type="U64int"/>
+ * </struct>
+ */
+struct Arena
+{
+	QLock		lock;			/* lock for arena fields, writing to disk */
+	Part		*part;			/* partition in which arena lives */
+	int		blocksize;		/* size of block to read or write */
+	u64int		base;			/* base address on disk */
+	u64int		size;			/* total space in the arena */
+	u64int		limit;			/* storage limit for clumps */
+	u8int		score[VtScoreSize];	/* score of the entire sealed & summed arena */
+
+	int		clumpmax;		/* ClumpInfos per block */
+	CIBlock		cib;			/* dirty clump directory block */
+
+	/*
+	 * fields stored on disk
+	 */
+	u32int		version;
+	char		name[ANameSize];	/* text label */
+	u32int		clumps;			/* number of allocated clumps */
+	u32int		cclumps;		/* clumps which are compressed; informational only */
+	u32int		ctime;			/* first time a block was written */
+	u32int		wtime;			/* last time a block was written */
+	u64int		used;			/* number of bytes currently used */
+	u64int		uncsize;		/* total of all clumps's uncsize; informational only */
+	u8int		sealed;			/* arena all filled up? */
+};
+
+/*
+ * redundant storage of some fields at the beginning of each arena
+ */
+struct ArenaHead
+{
+	u32int		version;
+	char		name[ANameSize];
+	u32int		blocksize;
+	u64int		size;
+};
+
+/*
+ * most interesting meta information for a clump.
+ * stored in each clump's header and in the Arena's directory,
+ * stored in reverse order just prior to the arena trailer
+ */
+struct ClumpInfo
+{
+	u8int		type;
+	u16int		size;			/* size of disk data, not including header */
+	u16int		uncsize;		/* size of uncompressed data */
+	u8int		score[VtScoreSize];	/* score of the uncompressed data only */
+};
+
+/*
+ * header for an immutable clump of data
+ */
+struct Clump
+{
+	ClumpInfo	info;
+	u8int		encoding;
+	u32int		creator;		/* initial client which wrote the block */
+	u32int		time;			/* creation at gmt seconds since 1/1/1970 */
+};
+
+/*
+ * index of all clumps according to their score
+ * this is just a wrapper to tie together the index sections
+ * <struct name="Index" type="Index *">
+ *	<field name="name" val="s->name" type="AName"/>
+ *	<field name="version" val="s->version" type="U32int"/>
+ *	<field name="blocksize" val="s->blocksize" type="U32int"/>
+ *	<field name="tabsize" val="s->tabsize" type="U32int"/>
+ *	<field name="buckets" val="s->buckets" type="U32int"/>
+ *	<field name="buckdiv" val="s->div" type="U32int"/>
+ *	<array name="sect" val="&s->smap[i]" elems="s->nsects" type="Amap"/>
+ *	<array name="amap" val="&s->amap[i]" elems="s->narenas" type="Amap"/>
+ *	<array name="arena" val="s->arenas[i]" elems="s->narenas" type="Arena"/>
+ * </struct>
+ * <struct name="Amap" type="AMap *">
+ *	<field name="name" val="s->name" type="AName"/>
+ *	<field name="start" val="s->start" type="U64int"/>
+ *	<field name="stop" val="s->stop" type="U64int"/>
+ * </struct>
+ */
+struct Index
+{
+	u32int		div;			/* divisor for mapping score to bucket */
+	u32int		buckets;		/* last bucket used in disk hash table */
+	u32int		blocksize;
+	u32int		tabsize;		/* max. bytes in index config */
+	int		mapalloc;		/* first arena to check when adding a lump */
+	Arena		**arenas;		/* arenas in the mapping */
+	ISect		**sects;		/* sections which hold the buckets */
+
+	/*
+	 * fields stored in config file 
+	 */
+	u32int		version;
+	char		name[ANameSize];	/* text label */
+	int		nsects;
+	AMap		*smap;			/* mapping of buckets to index sections */
+	int		narenas;
+	AMap		*amap;			/* mapping from index addesses to arenas */
+};
+
+/*
+ * one part of the bucket storage for an index.
+ * the index blocks are sequentially allocated
+ * across all of the sections.
+ */
+struct ISect
+{
+	Part		*part;
+	int		blocklog;		/* log2(blocksize) */
+	int		buckmax;		/* max. entries in a index bucket */
+	u32int		tabbase;		/* base address of index config table on disk */
+	u32int		tabsize;		/* max. bytes in index config */
+
+	/*
+	 * fields stored on disk
+	 */
+	u32int		version;
+	char		name[ANameSize];	/* text label */
+	char		index[ANameSize];	/* index owning the section */
+	u32int		blocksize;		/* size of hash buckets in index */
+	u32int		blockbase;		/* address of start of on disk index table */
+	u32int		blocks;			/* total blocks on disk; some may be unused */
+	u32int		start;			/* first bucket in this section */
+	u32int		stop;			/* limit of buckets in this section */
+};
+
+/*
+ * externally interesting part of an IEntry
+ */
+struct IAddr
+{
+	u64int		addr;
+	u16int		size;			/* uncompressed size */
+	u8int		type;			/* type of block */
+	u8int		blocks;			/* arena io quanta for Clump + data */
+};
+
+/*
+ * entries in the index
+ * kept in IBuckets in the disk index table,
+ * cached in the memory ICache.
+ */
+struct IEntry
+{
+	u8int		score[VtScoreSize];
+	IEntry		*next;			/* next in hash chain */
+	u32int		wtime;			/* last write time */
+	u16int		train;			/* relative train containing the most recent ref; 0 if no ref, 1 if in same car */
+	u8int		rac;			/* read ahead count */
+	IAddr		ia;
+};
+
+/*
+ * buckets in the on disk index table
+ */
+struct IBucket
+{
+	u16int		n;			/* number of active indices */
+	u32int		next;			/* overflow bucket */
+	u8int		*data;
+};
+
+/*
+ * temporary buffers used by individual threads
+ */
+struct ZBlock
+{
+	u32int		len;
+	u8int		*data;
+};
+
+/*
+ * simple input buffer for a '\0' terminated text file
+ */
+struct IFile
+{
+	char		*name;				/* name of the file */
+	ZBlock		*b;				/* entire contents of file */
+	u32int		pos;				/* current position in the file */
+};
+
+/*
+ * statistics about the operation of the server
+ * mainly for performance monitoring and profiling.
+ */
+struct Stats
+{
+	QLock		lock;
+	long		lumpwrites;		/* protocol block writes */
+	long		lumpreads;		/* protocol block reads */
+	long		lumphit;		/* lump cache hit */
+	long		lumpmiss;		/* lump cache miss */
+	long		clumpwrites;		/* clumps to disk */
+	vlong		clumpbwrites;		/* clump data bytes to disk */
+	vlong		clumpbcomp;		/* clump bytes compressed */
+	long		clumpreads;		/* clumps from disk */
+	vlong		clumpbreads;		/* clump data bytes from disk */
+	vlong		clumpbuncomp;		/* clump bytes uncompressed */
+	long		ciwrites;		/* clump directory to disk */
+	long		cireads;		/* clump directory from disk */
+	long		indexwrites;		/* index to disk */
+	long		indexreads;		/* index from disk */
+	long		indexwreads;		/* for writing a new entry */
+	long		indexareads;		/* for allocating an overflow block */
+	long		diskwrites;		/* total disk writes */
+	long		diskreads;		/* total disk reads */
+	vlong		diskbwrites;		/* total disk bytes written */
+	vlong		diskbreads;		/* total disk bytes read */
+	long		pchit;			/* partition cache hit */
+	long		pcmiss;			/* partition cache miss */
+	long		pcreads;		/* partition cache reads from disk */
+	vlong		pcbreads;		/* partition cache bytes read */
+	long		icinserts;		/* stores into index cache */
+	long		iclookups;		/* index cache lookups */
+	long		ichits;			/* hits in the cache */
+	long		icfills;		/* successful fills from index */
+};
+
+extern	Index		*mainindex;
+extern	u32int		maxblocksize;		/* max. block size used by any partition */
+extern	int		paranoid;		/* should verify hashes on disk read */
+extern	int		queuewrites;		/* put all lump writes on a queue and finish later */
+extern	int		readonly;		/* only allowed to read the disk data */
+extern	Stats		stats;
+extern	u8int		zeroscore[VtScoreSize];
diff --git a/src/cmd/venti/dcache.c b/src/cmd/venti/dcache.c
new file mode 100644
index 00000000..64b56847
--- /dev/null
+++ b/src/cmd/venti/dcache.c
@@ -0,0 +1,372 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+typedef struct DCache	DCache;
+
+enum
+{
+	HashLog		= 9,
+	HashSize	= 1<<HashLog,
+	HashMask	= HashSize - 1,
+};
+
+struct DCache
+{
+	QLock		lock;
+	Rendez		full;
+	DBlock		*free;			/* list of available lumps */
+	u32int		now;			/* ticks for usage timestamps */
+	int		size;			/* max. size of any block; allocated to each block */
+	DBlock		**heads;		/* hash table for finding address */
+	int		nheap;			/* number of available victims */
+	DBlock		**heap;			/* heap for locating victims */
+	int		nblocks;		/* number of blocks allocated */
+	DBlock		*blocks;		/* array of block descriptors */
+	u8int		*mem;			/* memory for all block descriptors */
+};
+
+static DCache	dcache;
+
+static int	downheap(int i, DBlock *b);
+static int	upheap(int i, DBlock *b);
+static DBlock	*bumpdblock(void);
+static void	delheap(DBlock *db);
+static void	fixheap(int i, DBlock *b);
+
+void
+initdcache(u32int mem)
+{
+	DBlock *b, *last;
+	u32int nblocks, blocksize;
+	int i;
+
+	if(mem < maxblocksize * 2)
+		sysfatal("need at least %d bytes for the disk cache", maxblocksize * 2);
+	if(maxblocksize == 0)
+		sysfatal("no max. block size given for disk cache");
+	blocksize = maxblocksize;
+	nblocks = mem / blocksize;
+	if(0)
+		fprint(2, "initialize disk cache with %d blocks of %d bytes\n", nblocks, blocksize);
+	dcache.full.l = &dcache.lock;
+	dcache.nblocks = nblocks;
+	dcache.size = blocksize;
+	dcache.heads = MKNZ(DBlock*, HashSize);
+	dcache.heap = MKNZ(DBlock*, nblocks);
+	dcache.blocks = MKNZ(DBlock, nblocks);
+	dcache.mem = MKNZ(u8int, nblocks * blocksize);
+
+	last = nil;
+	for(i = 0; i < nblocks; i++){
+		b = &dcache.blocks[i];
+		b->data = &dcache.mem[i * blocksize];
+		b->heap = TWID32;
+		b->next = last;
+		last = b;
+	}
+	dcache.free = last;
+	dcache.nheap = 0;
+}
+
+static u32int
+pbhash(u64int addr)
+{
+	u32int h;
+
+#define hashit(c)	((((c) * 0x6b43a9b5) >> (32 - HashLog)) & HashMask)
+	h = (addr >> 32) ^ addr;
+	return hashit(h);
+}
+
+DBlock*
+getdblock(Part *part, u64int addr, int read)
+{
+	DBlock *b;
+	u32int h, size;
+
+	size = part->blocksize;
+	if(size > dcache.size){
+		seterr(EAdmin, "block size %d too big for cache", size);
+		return nil;
+	}
+	h = pbhash(addr);
+
+	/*
+	 * look for the block in the cache
+	 */
+//checkdcache();
+	qlock(&dcache.lock);
+again:
+	for(b = dcache.heads[h]; b != nil; b = b->next){
+		if(b->part == part && b->addr == addr){
+			qlock(&stats.lock);
+			stats.pchit++;
+			qunlock(&stats.lock);
+			goto found;
+		}
+	}
+	qlock(&stats.lock);
+	stats.pcmiss++;
+	qunlock(&stats.lock);
+
+	/*
+	 * missed: locate the block with the oldest second to last use.
+	 * remove it from the heap, and fix up the heap.
+	 */
+	b = bumpdblock();
+	if(b == nil){
+		logerr(EAdmin, "all disk cache blocks in use");
+		rsleep(&dcache.full);
+		goto again;
+	}
+
+	/*
+	 * the new block has no last use, so assume it happens sometime in the middle
+ZZZ this is not reasonable
+	 */
+	b->used = (b->used2 + dcache.now) / 2;
+
+	/*
+	 * rechain the block on the correct hash chain
+	 */
+	b->next = dcache.heads[h];
+	dcache.heads[h] = b;
+	if(b->next != nil)
+		b->next->prev = b;
+	b->prev = nil;
+
+	b->addr = addr;
+	b->part = part;
+	b->size = 0;
+
+found:
+	b->ref++;
+	b->used2 = b->used;
+	b->used = dcache.now++;
+	if(b->heap != TWID32)
+		fixheap(b->heap, b);
+
+	qunlock(&dcache.lock);
+//checkdcache();
+
+	qlock(&b->lock);
+	if(b->size != size){
+		if(b->size < size){
+			if(!read)
+				memset(&b->data[b->size], 0, size - b->size);
+			else{
+				if(readpart(part, addr + b->size, &b->data[b->size], size - b->size) < 0){
+					putdblock(b);
+					return nil;
+				}
+				qlock(&stats.lock);
+				stats.pcreads++;
+				stats.pcbreads += size - b->size;
+				qunlock(&stats.lock);
+			}
+		}
+		b->size = size;
+	}
+
+	return b;
+}
+
+void
+putdblock(DBlock *b)
+{
+	if(b == nil)
+		return;
+
+	qunlock(&b->lock);
+//checkdcache();
+	qlock(&dcache.lock);
+	if(--b->ref == 0){
+		if(b->heap == TWID32)
+			upheap(dcache.nheap++, b);
+		rwakeup(&dcache.full);
+	}
+
+	qunlock(&dcache.lock);
+//checkdcache();
+}
+
+/*
+ * remove some block from use and update the free list and counters
+ */
+static DBlock*
+bumpdblock(void)
+{
+	DBlock *b;
+	ulong h;
+
+	b = dcache.free;
+	if(b != nil){
+		dcache.free = b->next;
+		return b;
+	}
+
+	/*
+	 * remove blocks until we find one that is unused
+	 * referenced blocks are left in the heap even though
+	 * they can't be scavenged; this is simple a speed optimization
+	 */
+	for(;;){
+		if(dcache.nheap == 0)
+			return nil;
+		b = dcache.heap[0];
+		delheap(b);
+		if(!b->ref)
+			break;
+	}
+
+	/*
+	 * unchain the block
+	 */
+	if(b->prev == nil){
+		h = pbhash(b->addr);
+		if(dcache.heads[h] != b)
+			sysfatal("bad hash chains in disk cache");
+		dcache.heads[h] = b->next;
+	}else
+		b->prev->next = b->next;
+	if(b->next != nil)
+		b->next->prev = b->prev;
+
+	return b;
+}
+
+/*
+ * delete an arbitrary block from the heap
+ */
+static void
+delheap(DBlock *db)
+{
+	fixheap(db->heap, dcache.heap[--dcache.nheap]);
+	db->heap = TWID32;
+}
+
+/*
+ * push an element up or down to it's correct new location
+ */
+static void
+fixheap(int i, DBlock *b)
+{
+	if(upheap(i, b) == i)
+		downheap(i, b);
+}
+
+static int
+upheap(int i, DBlock *b)
+{
+	DBlock *bb;
+	u32int now;
+	int p;
+
+	now = dcache.now;
+	for(; i != 0; i = p){
+		p = (i - 1) >> 1;
+		bb = dcache.heap[p];
+		if(b->used2 - now >= bb->used2 - now)
+			break;
+		dcache.heap[i] = bb;
+		bb->heap = i;
+	}
+
+	dcache.heap[i] = b;
+	b->heap = i;
+	return i;
+}
+
+static int
+downheap(int i, DBlock *b)
+{
+	DBlock *bb;
+	u32int now;
+	int k;
+
+	now = dcache.now;
+	for(; ; i = k){
+		k = (i << 1) + 1;
+		if(k >= dcache.nheap)
+			break;
+		if(k + 1 < dcache.nheap && dcache.heap[k]->used2 - now > dcache.heap[k + 1]->used2 - now)
+			k++;
+		bb = dcache.heap[k];
+		if(b->used2 - now <= bb->used2 - now)
+			break;
+		dcache.heap[i] = bb;
+		bb->heap = i;
+	}
+
+	dcache.heap[i] = b;
+	b->heap = i;
+	return i;
+}
+
+static void
+findblock(DBlock *bb)
+{
+	DBlock *b, *last;
+	int h;
+
+	last = nil;
+	h = pbhash(bb->addr);
+	for(b = dcache.heads[h]; b != nil; b = b->next){
+		if(last != b->prev)
+			sysfatal("bad prev link");
+		if(b == bb)
+			return;
+		last = b;
+	}
+	sysfatal("block missing from hash table");
+}
+
+void
+checkdcache(void)
+{
+	DBlock *b;
+	u32int size, now;
+	int i, k, refed, nfree;
+
+	qlock(&dcache.lock);
+	size = dcache.size;
+	now = dcache.now;
+	for(i = 0; i < dcache.nheap; i++){
+		if(dcache.heap[i]->heap != i)
+			sysfatal("dc: mis-heaped at %d: %d", i, dcache.heap[i]->heap);
+		if(i > 0 && dcache.heap[(i - 1) >> 1]->used2 - now > dcache.heap[i]->used2 - now)
+			sysfatal("dc: bad heap ordering");
+		k = (i << 1) + 1;
+		if(k < dcache.nheap && dcache.heap[i]->used2 - now > dcache.heap[k]->used2 - now)
+			sysfatal("dc: bad heap ordering");
+		k++;
+		if(k < dcache.nheap && dcache.heap[i]->used2 - now > dcache.heap[k]->used2 - now)
+			sysfatal("dc: bad heap ordering");
+	}
+
+	refed = 0;
+	for(i = 0; i < dcache.nblocks; i++){
+		b = &dcache.blocks[i];
+		if(b->data != &dcache.mem[i * size])
+			sysfatal("dc: mis-blocked at %d", i);
+		if(b->ref && b->heap == TWID32)
+			refed++;
+		if(b->addr)
+			findblock(b);
+		if(b->heap != TWID32
+		&& dcache.heap[b->heap] != b)
+			sysfatal("dc: spurious heap value");
+	}
+
+	nfree = 0;
+	for(b = dcache.free; b != nil; b = b->next){
+		if(b->addr != 0 || b->heap != TWID32)
+			sysfatal("dc: bad free list");
+		nfree++;
+	}
+
+	if(dcache.nheap + nfree + refed != dcache.nblocks)
+		sysfatal("dc: missing blocks: %d %d %d", dcache.nheap, refed, dcache.nblocks);
+	qunlock(&dcache.lock);
+}
diff --git a/src/cmd/venti/dump.c b/src/cmd/venti/dump.c
new file mode 100644
index 00000000..12fcddda
--- /dev/null
+++ b/src/cmd/venti/dump.c
@@ -0,0 +1,47 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+void
+printindex(int fd, Index *ix)
+{
+	int i;
+
+	fprint(fd, "index=%s version=%d blocksize=%d tabsize=%d\n",
+		ix->name, ix->version, ix->blocksize, ix->tabsize);
+	fprint(fd, "\tbuckets=%d div=%d\n", ix->buckets, ix->div);
+	for(i = 0; i < ix->nsects; i++)
+		fprint(fd, "\tsect=%s for buckets [%lld,%lld)\n", ix->smap[i].name, ix->smap[i].start, ix->smap[i].stop);
+	for(i = 0; i < ix->narenas; i++)
+		fprint(fd, "\tarena=%s at [%lld,%lld)\n", ix->amap[i].name, ix->amap[i].start, ix->amap[i].stop);
+}
+
+void
+printarenapart(int fd, ArenaPart *ap)
+{
+	int i;
+
+	fprint(fd, "arena partition=%s\n\tversion=%d blocksize=%d arenas=%d\n\tsetbase=%d setsize=%d\n",
+		ap->part->name, ap->version, ap->blocksize, ap->narenas, ap->tabbase, ap->tabsize);
+	for(i = 0; i < ap->narenas; i++)
+		fprint(fd, "\tarena=%s at [%lld,%lld)\n", ap->map[i].name, ap->map[i].start, ap->map[i].stop);
+}
+
+void
+printarena(int fd, Arena *arena)
+{
+	fprint(fd, "arena='%s' [%lld,%lld)\n\tversion=%d created=%d modified=%d",
+		arena->name, arena->base, arena->base + arena->size + 2 * arena->blocksize,
+		arena->version, arena->ctime, arena->wtime);
+	if(arena->sealed)
+		fprint(2, " sealed\n");
+	else
+		fprint(2, "\n");
+	if(scorecmp(zeroscore, arena->score) != 0)
+		fprint(2, "\tscore=%V\n", arena->score);
+
+	fprint(fd, "\tclumps=%,d compressed clumps=%,d data=%,lld compressed data=%,lld disk storage=%,lld\n",
+		arena->clumps, arena->cclumps, arena->uncsize,
+		arena->used - arena->clumps * ClumpSize,
+		arena->used + arena->clumps * ClumpInfoSize);
+}
diff --git a/src/cmd/venti/findscore.c b/src/cmd/venti/findscore.c
new file mode 100644
index 00000000..6a69dc53
--- /dev/null
+++ b/src/cmd/venti/findscore.c
@@ -0,0 +1,132 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+enum
+{
+	ClumpChunks	= 32*1024
+};
+
+static int	verbose;
+
+int
+clumpinfoeq(ClumpInfo *c, ClumpInfo *d)
+{
+	return c->type == d->type
+		&& c->size == d->size
+		&& c->uncsize == d->uncsize
+		&& scorecmp(c->score, d->score)==0;
+}
+
+/*
+ * synchronize the clump info directory with
+ * with the clumps actually stored in the arena.
+ * the directory should be at least as up to date
+ * as the arena's trailer.
+ *
+ * checks/updates at most n clumps.
+ *
+ * returns 1 if ok, -1 if an error occured, 0 if blocks were updated
+ */
+int
+findscore(Arena *arena, uchar *score)
+{
+	IEntry ie;
+	ClumpInfo *ci, *cis;
+	u64int a;
+	u32int clump;
+	int i, n, found;
+
+//ZZZ remove fprint?
+	if(arena->clumps)
+		fprint(2, "reading directory for arena=%s with %d entries\n", arena->name, arena->clumps);
+
+	cis = MKN(ClumpInfo, ClumpChunks);
+	found = 0;
+	a = 0;
+	memset(&ie, 0, sizeof(IEntry));
+	for(clump = 0; clump < arena->clumps; clump += n){
+		n = ClumpChunks;
+		if(n > arena->clumps - clump)
+			n = arena->clumps - clump;
+		if(readclumpinfos(arena, clump, cis, n) != n){
+			seterr(EOk, "arena directory read failed: %r");
+			break;
+		}
+
+		for(i = 0; i < n; i++){
+			ci = &cis[i];
+			if(scorecmp(score, ci->score)==0){
+				fprint(2, "found at clump=%d with type=%d size=%d csize=%d position=%lld\n",
+					clump + i, ci->type, ci->uncsize, ci->size, a);
+				found++;
+			}
+			a += ci->size + ClumpSize;
+		}
+	}
+	free(cis);
+	return found;
+}
+
+void
+usage(void)
+{
+	fprint(2, "usage: findscore [-v] arenafile score\n");
+	threadexitsall(0);
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	ArenaPart *ap;
+	Part *part;
+	char *file;
+	u8int score[VtScoreSize];
+	int i, found;
+
+	fmtinstall('V', vtscorefmt);
+	statsinit();
+
+	ARGBEGIN{
+	case 'v':
+		verbose++;
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	readonly = 1;
+
+	if(argc != 2)
+		usage();
+
+	file = argv[0];
+	if(strscore(argv[1], score) < 0)
+		sysfatal("bad score %s\n", argv[1]);
+
+	part = initpart(file, 0);
+	if(part == nil)
+		sysfatal("can't open partition %s: %r", file);
+
+	ap = initarenapart(part);
+	if(ap == nil)
+		sysfatal("can't initialize arena partition in %s: %r", file);
+
+	if(verbose > 1){
+		printarenapart(2, ap);
+		fprint(2, "\n");
+	}
+
+	initdcache(8 * MaxDiskBlock);
+
+	found = 0;
+	for(i = 0; i < ap->narenas; i++)
+		found += findscore(ap->arenas[i], score);
+
+	print("found %d occurances of %V\n", found, score);
+
+	if(verbose > 1)
+		printstats();
+	threadexitsall(0);
+}
diff --git a/src/cmd/venti/fmtarenas.c b/src/cmd/venti/fmtarenas.c
new file mode 100644
index 00000000..8e52c56b
--- /dev/null
+++ b/src/cmd/venti/fmtarenas.c
@@ -0,0 +1,114 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+void
+usage(void)
+{
+	fprint(2, "usage: fmtarenas [-Z] [-b blocksize] [-a arenasize] name file\n");
+	threadexitsall(0);
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	ArenaPart *ap;
+	Part *part;
+	Arena *arena;
+	u64int addr, limit, asize, apsize;
+	char *file, *name, aname[ANameSize];
+	int i, n, blocksize, tabsize, zero;
+
+	fmtinstall('V', vtscorefmt);
+
+	statsinit();
+
+	blocksize = 8 * 1024;
+	asize = 512 * 1024 *1024;
+	tabsize = 64 * 1024;		/* BUG: should be determine from number of arenas */
+	zero = 1;
+	ARGBEGIN{
+	case 'a':
+		asize = unittoull(ARGF());
+		if(asize == TWID64)
+			usage();
+		break;
+	case 'b':
+		blocksize = unittoull(ARGF());
+		if(blocksize == ~0)
+			usage();
+		if(blocksize > MaxDiskBlock){
+			fprint(2, "block size too large, max %d\n", MaxDiskBlock);
+			threadexitsall("usage");
+		}
+		break;
+	case 'Z':
+		zero = 0;
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	if(argc != 2)
+		usage();
+
+	name = argv[0];
+	file = argv[1];
+
+	if(nameok(name) < 0)
+		sysfatal("illegal name template %s", name);
+
+	part = initpart(file, 1);
+	if(part == nil)
+		sysfatal("can't open partition %s: %r", file);
+
+	if(zero)
+		zeropart(part, blocksize);
+
+	ap = newarenapart(part, blocksize, tabsize);
+	if(ap == nil)
+		sysfatal("can't initialize arena: %r");
+
+	apsize = ap->size - ap->arenabase;
+	n = apsize / asize;
+	if(apsize - (n * asize) >= MinArenaSize)
+		n++;
+	
+	fprint(2, "configuring %s with arenas=%d for a total storage of bytes=%lld and directory bytes=%d\n",
+		file, n, apsize, ap->tabsize);
+
+	ap->narenas = n;
+	ap->map = MKNZ(AMap, n);
+	ap->arenas = MKNZ(Arena*, n);
+
+	addr = ap->arenabase;
+	for(i = 0; i < n; i++){
+		limit = addr + asize;
+		if(limit >= ap->size || ap->size - limit < MinArenaSize){
+			limit = ap->size;
+			if(limit - addr < MinArenaSize)
+				sysfatal("bad arena set math: runt arena at %lld,%lld %lld\n", addr, limit, ap->size);
+		}
+
+		snprint(aname, ANameSize, "%s%d", name, i);
+
+		fprint(2, "adding arena %s at [%lld,%lld)\n", aname, addr, limit);
+
+		arena = newarena(part, aname, addr, limit - addr, blocksize);
+		if(!arena)
+			fprint(2, "can't make new arena %s: %r", aname);
+		freearena(arena);
+
+		ap->map[i].start = addr;
+		ap->map[i].stop = limit;
+		namecp(ap->map[i].name, aname);
+
+		addr = limit;
+	}
+
+	if(wbarenapart(ap) < 0)
+		fprint(2, "can't write back arena partition header for %s: %r\n", file);
+
+	threadexitsall(0);
+}
diff --git a/src/cmd/venti/fmtindex.c b/src/cmd/venti/fmtindex.c
new file mode 100644
index 00000000..19daa8e1
--- /dev/null
+++ b/src/cmd/venti/fmtindex.c
@@ -0,0 +1,117 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+void
+usage(void)
+{
+	fprint(2, "usage: fmtindex config\n");
+	threadexitsall(0);
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	Config conf;
+	Index *ix;
+	ArenaPart *ap;
+	Arena **arenas;
+	AMap *amap;
+	u64int addr;
+	char *file;
+	u32int i, j, n, narenas;
+	int add;
+
+	fmtinstall('V', vtscorefmt);
+	statsinit();
+
+	add = 0;
+	ARGBEGIN{
+	case 'a':
+		add = 1;
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	if(argc != 1)
+		usage();
+
+	file = argv[0];
+
+	if(runconfig(file, &conf) < 0)
+		sysfatal("can't initialize config %s: %r", file);
+	if(conf.index == nil)
+		sysfatal("no index specified in %s", file);
+	if(nameok(conf.index) < 0)
+		sysfatal("illegal index name %s", conf.index);
+
+	narenas = 0;
+	for(i = 0; i < conf.naparts; i++){
+		ap = conf.aparts[i];
+		narenas += ap->narenas;
+	}
+
+	if(add){
+		ix = initindex(conf.index, conf.sects, conf.nsects);
+		if(ix == nil)
+			sysfatal("can't initialize index %s: %r", conf.index);
+	}else{
+		ix = newindex(conf.index, conf.sects, conf.nsects);
+		if(ix == nil)
+			sysfatal("can't create new index %s: %r", conf.index);
+
+		n = 0;
+		for(i = 0; i < ix->nsects; i++)
+			n += ix->sects[i]->blocks;
+
+		if(ix->div < 100)
+			sysfatal("index divisor too coarse: use bigger block size");
+
+		fprint(2, "using %ud buckets of %ud; div=%d\n", ix->buckets, n, ix->div);
+	}
+	amap = MKNZ(AMap, narenas);
+	arenas = MKNZ(Arena*, narenas);
+
+	addr = IndexBase;
+	n = 0;
+	for(i = 0; i < conf.naparts; i++){
+		ap = conf.aparts[i];
+		for(j = 0; j < ap->narenas; j++){
+			if(n >= narenas)
+				sysfatal("too few slots in index's arena set");
+
+			arenas[n] = ap->arenas[j];
+			if(n < ix->narenas){
+				if(arenas[n] != ix->arenas[n])
+					sysfatal("mismatched arenas %s and %s at slot %d\n",
+						arenas[n]->name, ix->arenas[n]->name, n);
+				amap[n] = ix->amap[n];
+				if(amap[n].start != addr)
+					sysfatal("mis-located arena %s in index %s\n", arenas[n]->name, ix->name);
+				addr = amap[n].stop;
+			}else{
+				amap[n].start = addr;
+				addr += ap->arenas[j]->size;
+				amap[n].stop = addr;
+				namecp(amap[n].name, ap->arenas[j]->name);
+				fprint(2, "add arena %s at [%lld,%lld)\n",
+					amap[n].name, amap[n].start, amap[n].stop);
+			}
+
+			n++;
+		}
+	}
+	fprint(2, "configured index=%s with arenas=%d and storage=%lld\n",
+		ix->name, n, addr - IndexBase);
+
+	ix->amap = amap;
+	ix->arenas = arenas;
+	ix->narenas = narenas;
+
+	if(wbindex(ix) < 0)
+		fprint(2, "can't write back arena partition header for %s: %r\n", file);
+
+	threadexitsall(0);
+}
diff --git a/src/cmd/venti/fmtisect.c b/src/cmd/venti/fmtisect.c
new file mode 100644
index 00000000..77c92967
--- /dev/null
+++ b/src/cmd/venti/fmtisect.c
@@ -0,0 +1,69 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+void
+usage(void)
+{
+	fprint(2, "usage: fmtisect [-Z] [-b blocksize] name file\n");
+	threadexitsall(0);
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	ISect *is;
+	Part *part;
+	char *file, *name;
+	int blocksize, setsize, zero;
+
+	fmtinstall('V', vtscorefmt);
+	statsinit();
+
+	blocksize = 8 * 1024;
+	setsize = 64 * 1024;
+	zero = 1;
+	ARGBEGIN{
+	case 'b':
+		blocksize = unittoull(ARGF());
+		if(blocksize == ~0)
+			usage();
+		if(blocksize > MaxDiskBlock){
+			fprint(2, "block size too large, max %d\n", MaxDiskBlock);
+			threadexitsall("usage");
+		}
+		break;
+	case 'Z':
+		zero = 0;
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	if(argc != 2)
+		usage();
+
+	name = argv[0];
+	file = argv[1];
+
+	if(nameok(name) < 0)
+		sysfatal("illegal name %s", name);
+
+	part = initpart(file, 0);
+	if(part == nil)
+		sysfatal("can't open partition %s: %r", file);
+
+	if(zero)
+		zeropart(part, blocksize);
+
+	fprint(2, "configuring index section %s with space for index config bytes=%d\n", name, setsize);
+	is = newisect(part, name, blocksize, setsize);
+	if(is == nil)
+		sysfatal("can't initialize new index: %r");
+
+	if(wbisect(is) < 0)
+		fprint(2, "can't write back index section header for %s: %r\n", file);
+
+	threadexitsall(0);
+}
diff --git a/src/cmd/venti/fns.h b/src/cmd/venti/fns.h
new file mode 100644
index 00000000..4503d539
--- /dev/null
+++ b/src/cmd/venti/fns.h
@@ -0,0 +1,161 @@
+/*
+ * sorted by 4,/^$/|sort -bd +1
+ */
+int		addarena(Arena *name);
+ZBlock		*alloczblock(u32int size, int zeroed);
+Arena		*amapitoa(Index *index, u64int a, u64int *aa);
+u64int		arenadirsize(Arena *arena, u32int clumps);
+void		arenaupdate(Arena *arena, u32int size, u8int *score);
+void		backsumarena(Arena *arena);
+u32int		buildbucket(Index *ix, IEStream *ies, IBucket *ib);
+void		checkdcache(void);
+void		checklumpcache(void);
+int		clumpinfoeq(ClumpInfo *c, ClumpInfo *d);
+int		clumpinfoeq(ClumpInfo *c, ClumpInfo *d);
+u32int		clumpmagic(Arena *arena, u64int aa);
+int		delarena(Arena *arena);
+void		*emalloc(ulong);
+void		*erealloc(void *, ulong);
+char		*estrdup(char*);
+void		*ezmalloc(ulong);
+Arena		*findarena(char *name);
+ISect		*findisect(Index *ix, u32int buck);
+int		flushciblocks(Arena *arena);
+void		fmtzbinit(Fmt *f, ZBlock *b);
+void		freearena(Arena *arena);
+void		freearenapart(ArenaPart *ap, int freearenas);
+void		freeiestream(IEStream *ies);
+void		freeifile(IFile *f);
+void		freeisect(ISect *is);
+void		freeindex(Index *index);
+void		freepart(Part *part);
+void		freezblock(ZBlock *b);
+DBlock		*getdblock(Part *part, u64int addr, int read);
+u32int		hashbits(u8int *score, int nbits);
+int		httpdinit(char *address);
+int		iaddrcmp(IAddr *ia1, IAddr *ia2);
+int		ientrycmp(const void *vie1, const void *vie2);
+char		*ifileline(IFile *f);
+int		ifilename(IFile *f, char *dst);
+int		ifileu32int(IFile *f, u32int *r);
+int		indexsect(Index *ix, u8int *score);
+Arena		*initarena(Part *part, u64int base, u64int size, u32int blocksize);
+ArenaPart	*initarenapart(Part *part);
+int		initarenasum(void);
+void		initdcache(u32int mem);
+void		initicache(int bits, int depth);
+IEStream	*initiestream(Part *part, u64int off, u64int clumps, u32int size);
+ISect		*initisect(Part *part);
+Index		*initindex(char *name, ISect **sects, int n);
+void		initlumpcache(u32int size, u32int nblocks);
+int		initlumpqueues(int nq);
+Part*		initpart(char *name, int writable);
+int		initventi(char *config);
+void		insertlump(Lump *lump, Packet *p);
+int		insertscore(u8int *score, IAddr *ia, int write);
+ZBlock		*loadclump(Arena *arena, u64int aa, int blocks, Clump *cl, u8int *score, int verify);
+int		loadientry(Index *index, u8int *score, int type, IEntry *ie);
+void		logerr(int severity, char *fmt, ...);
+Lump		*lookuplump(u8int *score, int type);
+int		lookupscore(u8int *score, int type, IAddr *ia, int *rac);
+int		maparenas(AMap *am, Arena **arenas, int n, char *what);
+int		namecmp(char *s, char *t);
+void		namecp(char *dst, char *src);
+int		nameok(char *name);
+Arena		*newarena(Part *part, char *name, u64int base, u64int size, u32int blocksize);
+ArenaPart	*newarenapart(Part *part, u32int blocksize, u32int tabsize);
+ISect		*newisect(Part *part, char *name, u32int blocksize, u32int tabsize);
+Index		*newindex(char *name, ISect **sects, int n);
+u32int		now(void);
+int		okamap(AMap *am, int n, u64int start, u64int stop, char *what);
+int		outputamap(Fmt *f, AMap *am, int n);
+int		outputindex(Fmt *f, Index *ix);
+int		packarena(Arena *arena, u8int *buf);
+int		packarenahead(ArenaHead *head, u8int *buf);
+int		packarenapart(ArenaPart *as, u8int *buf);
+int		packclump(Clump *c, u8int *buf);
+void		packclumpinfo(ClumpInfo *ci, u8int *buf);
+void		packibucket(IBucket *b, u8int *buf);
+void		packientry(IEntry *i, u8int *buf);
+int		packisect(ISect *is, u8int *buf);
+void		packmagic(u32int magic, u8int *buf);
+ZBlock		*packet2zblock(Packet *p, u32int size);
+int		parseamap(IFile *f, AMapN *amn);
+int		parseindex(IFile *f, Index *ix);
+void		partblocksize(Part *part, u32int blocksize);
+int		partifile(IFile *f, Part *part, u64int start, u32int size);
+void		printarenapart(int fd, ArenaPart *ap);
+void		printarena(int fd, Arena *arena);
+void		printindex(int fd, Index *ix);
+void		printstats(void);
+void		putdblock(DBlock *b);
+void		putlump(Lump *b);
+void		queueflush(void);
+int		queuewrite(Lump *b, Packet *p, int creator);
+u32int		readarena(Arena *arena, u64int aa, u8int *buf, long n);
+int		readarenamap(AMapN *amn, Part *part, u64int base, u32int size);
+int		readclumpinfo(Arena *arena, int clump, ClumpInfo *ci);
+int		readclumpinfos(Arena *arena, int clump, ClumpInfo *cis, int n);
+ZBlock		*readfile(char *name);
+int		readifile(IFile *f, char *name);
+Packet		*readlump(u8int *score, int type, u32int size);
+int		readpart(Part *part, u64int addr, u8int *buf, u32int n);
+int		runconfig(char *config, Config*);
+int		scorecmp(u8int *, u8int *);
+void		scoremem(u8int *score, u8int *buf, int size);
+void		seterr(int severity, char *fmt, ...);
+u64int		sortrawientries(Index *ix, Part *tmp, u64int *tmpoff);
+void		statsinit(void);
+int		storeclump(Index *index, ZBlock *b, u8int *score, int type, u32int creator, IAddr *ia);
+int		storeientry(Index *index, IEntry *m);
+int		strscore(char *s, u8int *score);
+int		stru32int(char *s, u32int *r);
+int		stru64int(char *s, u64int *r);
+void		sumarena(Arena *arena);
+int		syncarena(Arena *arena, u32int n, int zok, int fix);
+int		syncarenaindex(Index *ix, Arena *arena, u32int clump, u64int a, int fix);
+int		syncindex(Index *ix, int fix);
+int		u64log2(u64int v);
+u64int		unittoull(char *s);
+int		unpackarena(Arena *arena, u8int *buf);
+int		unpackarenahead(ArenaHead *head, u8int *buf);
+int		unpackarenapart(ArenaPart *as, u8int *buf);
+int		unpackclump(Clump *c, u8int *buf);
+void		unpackclumpinfo(ClumpInfo *ci, u8int *buf);
+void		unpackibucket(IBucket *b, u8int *buf);
+void		unpackientry(IEntry *i, u8int *buf);
+int		unpackisect(ISect *is, u8int *buf);
+u32int		unpackmagic(u8int *buf);
+int		vtproc(void(*)(void*), void*);
+int		vttypevalid(int type);
+int		wbarena(Arena *arena);
+int		wbarenahead(Arena *arena);
+int		wbarenamap(AMap *am, int n, Part *part, u64int base, u64int size);
+int		wbarenapart(ArenaPart *ap);
+int		wbisect(ISect *is);
+int		wbindex(Index *ix);
+int		whackblock(u8int *dst, u8int *src, int ssize);
+u64int		writeaclump(Arena *a, Clump *c, u8int *clbuf);
+u32int		writearena(Arena *arena, u64int aa, u8int *clbuf, u32int n);
+int		writeclumpinfo(Arena *arean, int clump, ClumpInfo *ci);
+u64int		writeiclump(Index *ix, Clump *c, u8int *clbuf);
+int		writelump(Packet *p, u8int *score, int type, u32int creator);
+int		writepart(Part *part, u64int addr, u8int *buf, u32int n);
+int		writeqlump(Lump *u, Packet *p, int creator);
+Packet		*zblock2packet(ZBlock *zb, u32int size);
+void		zeropart(Part *part, int blocksize);
+
+/*
+#pragma	varargck	argpos	sysfatal		1
+#pragma	varargck	argpos	logerr		2
+#pragma	varargck	argpos	SetErr		2
+*/
+
+#define scorecmp(h1,h2)		memcmp((h1),(h2),VtScoreSize)
+#define scorecp(h1,h2)		memmove((h1),(h2),VtScoreSize)
+
+#define MK(t)			((t*)emalloc(sizeof(t)))
+#define MKZ(t)			((t*)ezmalloc(sizeof(t)))
+#define MKN(t,n)		((t*)emalloc((n)*sizeof(t)))
+#define MKNZ(t,n)		((t*)ezmalloc((n)*sizeof(t)))
+#define MKNA(t,at,n)		((t*)emalloc(sizeof(t) + (n)*sizeof(at)))
diff --git a/src/cmd/venti/httpd.c b/src/cmd/venti/httpd.c
new file mode 100644
index 00000000..cd207cd1
--- /dev/null
+++ b/src/cmd/venti/httpd.c
@@ -0,0 +1,441 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+#include "httpd.h"
+#include "xml.h"
+
+typedef struct HttpObj	HttpObj;
+
+enum
+{
+	ObjNameSize	= 64,
+	MaxObjs		= 16
+};
+
+struct HttpObj
+{
+	char	name[ObjNameSize];
+	int	(*f)(HConnect*);
+};
+
+static HttpObj	objs[MaxObjs];
+
+static	void		listenproc(void*);
+static	int		estats(HConnect *c);
+static	int		dindex(HConnect *c);
+static	int		xindex(HConnect *c);
+static	int		sindex(HConnect *c);
+static	int		notfound(HConnect *c);
+static	int		httpdobj(char *name, int (*f)(HConnect*));
+
+int
+httpdinit(char *address)
+{
+	fmtinstall('D', hdatefmt);
+	fmtinstall('H', httpfmt);
+	fmtinstall('U', hurlfmt);
+
+	if(address == nil)
+		address = "tcp!*!http";
+
+	httpdobj("/stats", estats);
+	httpdobj("/index", dindex);
+	httpdobj("/storage", sindex);
+	httpdobj("/xindex", xindex);
+
+	if(vtproc(listenproc, address) < 0)
+		return -1;
+	return 0;
+}
+
+static int
+httpdobj(char *name, int (*f)(HConnect*))
+{
+	int i;
+
+	if(name == nil || strlen(name) >= ObjNameSize)
+		return -1;
+	for(i = 0; i < MaxObjs; i++){
+		if(objs[i].name[0] == '\0'){
+			strcpy(objs[i].name, name);
+			objs[i].f = f;
+			return 0;
+		}
+		if(strcmp(objs[i].name, name) == 0)
+			return -1;
+	}
+	return -1;
+}
+
+static HConnect*
+mkconnect(void)
+{
+	HConnect *c;
+
+	c = mallocz(sizeof(HConnect), 1);
+	if(c == nil)
+		sysfatal("out of memory");
+	c->replog = nil;
+	c->hpos = c->header;
+	c->hstop = c->header;
+	return c;
+}
+
+void httpproc(void*);
+
+static void
+listenproc(void *vaddress)
+{
+	HConnect *c;
+	char *address, ndir[NETPATHLEN], dir[NETPATHLEN];
+	int ctl, nctl, data;
+
+//sleep(1000);	/* let strace find us */
+
+	address = vaddress;
+	ctl = announce(address, dir);
+	if(ctl < 0){
+		fprint(2, "venti: httpd can't announce on %s: %r\n", address);
+		return;
+	}
+
+print("announce ctl %d dir %s\n", ctl, dir);
+	for(;;){
+		/*
+		 *  wait for a call (or an error)
+		 */
+		nctl = listen(dir, ndir);
+print("httpd listen %d %s...\n", nctl, ndir);
+		if(nctl < 0){
+			fprint(2, "venti: httpd can't listen on %s: %r\n", address);
+			return;
+		}
+
+		data = accept(ctl, ndir);
+print("httpd accept %d...\n", data);
+		if(data < 0){
+			fprint(2, "venti: httpd accept: %r\n");
+			close(nctl);
+			continue;
+		}
+print("httpd close nctl %d\n", nctl);
+		close(nctl);
+		c = mkconnect();
+		hinit(&c->hin, data, Hread);
+		hinit(&c->hout, data, Hwrite);
+		vtproc(httpproc, c);
+	}
+}
+
+void
+httpproc(void *v)
+{
+	HConnect *c;
+	int ok, t, i;
+
+//sleep(1000);	/* let strace find us */
+	c = v;
+
+	for(t = 15*60*1000; ; t = 15*1000){
+		if(hparsereq(c, t) <= 0)
+			break;
+
+		ok = -1;
+		for(i = 0; i < MaxObjs && objs[i].name[0]; i++){
+			if(strcmp(c->req.uri, objs[i].name) == 0){
+				ok = (*objs[i].f)(c);
+				break;
+			}
+		}
+		if(i == MaxObjs)
+			ok = notfound(c);
+		if(c->head.closeit)
+			ok = -1;
+		hreqcleanup(c);
+
+		if(ok < 0)
+			break;
+	}
+print("httpd cleanup %d\n", c->hin.fd);
+	hreqcleanup(c);
+print("close %d\n", c->hin.fd);
+	close(c->hin.fd);
+	free(c);
+}
+
+static int
+percent(long v, long total)
+{
+	if(total == 0)
+		total = 1;
+	if(v < 1000*1000)
+		return (v * 100) / total;
+	total /= 100;
+	if(total == 0)
+		total = 1;
+	return v / total;
+}
+
+static int
+preq(HConnect *c)
+{
+	if(hparseheaders(c, 15*60*1000) < 0)
+		return -1;
+	if(strcmp(c->req.meth, "GET") != 0
+	&& strcmp(c->req.meth, "HEAD") != 0)
+		return hunallowed(c, "GET, HEAD");
+	if(c->head.expectother || c->head.expectcont)
+		return hfail(c, HExpectFail, nil);
+	return 0;
+}
+
+static int
+preqtext(HConnect *c)
+{
+	Hio *hout;
+	int r;
+
+	r = preq(c);
+	if(r <= 0)
+		return r;
+
+	hout = &c->hout;
+	if(c->req.vermaj){
+		hokheaders(c);
+		hprint(hout, "Content-type: text/plain\r\n");
+		if(http11(c))
+			hprint(hout, "Transfer-Encoding: chunked\r\n");
+		hprint(hout, "\r\n");
+	}
+
+	if(http11(c))
+		hxferenc(hout, 1);
+	else
+		c->head.closeit = 1;
+	return 0;
+}
+
+static int
+notfound(HConnect *c)
+{
+	int r;
+
+	r = preq(c);
+	if(r <= 0)
+		return r;
+	return hfail(c, HNotFound, c->req.uri);
+}
+
+static int
+estats(HConnect *c)
+{
+	Hio *hout;
+	int r;
+
+	r = preqtext(c);
+	if(r <= 0)
+		return r;
+
+	hout = &c->hout;
+	hprint(hout, "lump writes=%,ld\n", stats.lumpwrites);
+	hprint(hout, "lump reads=%,ld\n", stats.lumpreads);
+	hprint(hout, "lump cache read hits=%,ld\n", stats.lumphit);
+	hprint(hout, "lump cache read misses=%,ld\n", stats.lumpmiss);
+
+	hprint(hout, "clump disk writes=%,ld\n", stats.clumpwrites);
+	hprint(hout, "clump disk bytes written=%,lld\n", stats.clumpbwrites);
+	hprint(hout, "clump disk bytes compressed=%,lld\n", stats.clumpbcomp);
+	hprint(hout, "clump disk reads=%,ld\n", stats.clumpreads);
+	hprint(hout, "clump disk bytes read=%,lld\n", stats.clumpbreads);
+	hprint(hout, "clump disk bytes uncompressed=%,lld\n", stats.clumpbuncomp);
+
+	hprint(hout, "clump directory disk writes=%,ld\n", stats.ciwrites);
+	hprint(hout, "clump directory disk reads=%,ld\n", stats.cireads);
+
+	hprint(hout, "index disk writes=%,ld\n", stats.indexwrites);
+	hprint(hout, "index disk reads=%,ld\n", stats.indexreads);
+	hprint(hout, "index disk reads for modify=%,ld\n", stats.indexwreads);
+	hprint(hout, "index disk reads for allocation=%,ld\n", stats.indexareads);
+
+	hprint(hout, "index cache lookups=%,ld\n", stats.iclookups);
+	hprint(hout, "index cache hits=%,ld %d%%\n", stats.ichits,
+		percent(stats.ichits, stats.iclookups));
+	hprint(hout, "index cache fills=%,ld %d%%\n", stats.icfills,
+		percent(stats.icfills, stats.iclookups));
+	hprint(hout, "index cache inserts=%,ld\n", stats.icinserts);
+
+	hprint(hout, "disk cache hits=%,ld\n", stats.pchit);
+	hprint(hout, "disk cache misses=%,ld\n", stats.pcmiss);
+	hprint(hout, "disk cache reads=%,ld\n", stats.pcreads);
+	hprint(hout, "disk cache bytes read=%,lld\n", stats.pcbreads);
+
+	hprint(hout, "disk writes=%,ld\n", stats.diskwrites);
+	hprint(hout, "disk bytes written=%,lld\n", stats.diskbwrites);
+	hprint(hout, "disk reads=%,ld\n", stats.diskreads);
+	hprint(hout, "disk bytes read=%,lld\n", stats.diskbreads);
+
+	hflush(hout);
+	return 0;
+}
+
+static int
+sindex(HConnect *c)
+{
+	Hio *hout;
+	Index *ix;
+	Arena *arena;
+	vlong clumps, cclumps, uncsize, used, size;
+	int i, r, active;
+
+	r = preqtext(c);
+	if(r <= 0)
+		return r;
+	hout = &c->hout;
+
+	ix = mainindex;
+
+	hprint(hout, "index=%s\n", ix->name);
+
+	active = 0;
+	clumps = 0;
+	cclumps = 0;
+	uncsize = 0;
+	used = 0;
+	size = 0;
+	for(i = 0; i < ix->narenas; i++){
+		arena = ix->arenas[i];
+		if(arena != nil && arena->clumps != 0){
+			active++;
+			clumps += arena->clumps;
+			cclumps += arena->cclumps;
+			uncsize += arena->uncsize;
+			used += arena->used;
+		}
+		size += arena->size;
+	}
+	hprint(hout, "total arenas=%d active=%d\n", ix->narenas, active);
+	hprint(hout, "total space=%lld used=%lld\n", size, used + clumps * ClumpInfoSize);
+	hprint(hout, "clumps=%lld compressed clumps=%lld data=%lld compressed data=%lld\n",
+		clumps, cclumps, uncsize, used - clumps * ClumpSize);
+	hflush(hout);
+	return 0;
+}
+
+static void
+darena(Hio *hout, Arena *arena)
+{
+	hprint(hout, "arena='%s' on %s at [%lld,%lld)\n\tversion=%d created=%d modified=%d",
+		arena->name, arena->part->name, arena->base, arena->base + arena->size + 2 * arena->blocksize,
+		arena->version, arena->ctime, arena->wtime);
+	if(arena->sealed)
+		hprint(hout, " sealed\n");
+	else
+		hprint(hout, "\n");
+	if(scorecmp(zeroscore, arena->score) != 0)
+		hprint(hout, "\tscore=%V\n", arena->score);
+
+	hprint(hout, "\tclumps=%d compressed clumps=%d data=%lld compressed data=%lld disk storage=%lld\n",
+		arena->clumps, arena->cclumps, arena->uncsize,
+		arena->used - arena->clumps * ClumpSize,
+		arena->used + arena->clumps * ClumpInfoSize);
+}
+
+static int
+dindex(HConnect *c)
+{
+	Hio *hout;
+	Index *ix;
+	int i, r;
+
+	r = preqtext(c);
+	if(r <= 0)
+		return r;
+	hout = &c->hout;
+
+
+	ix = mainindex;
+	hprint(hout, "index=%s version=%d blocksize=%d tabsize=%d\n",
+		ix->name, ix->version, ix->blocksize, ix->tabsize);
+	hprint(hout, "\tbuckets=%d div=%d\n", ix->buckets, ix->div);
+	for(i = 0; i < ix->nsects; i++)
+		hprint(hout, "\tsect=%s for buckets [%lld,%lld)\n", ix->smap[i].name, ix->smap[i].start, ix->smap[i].stop);
+	for(i = 0; i < ix->narenas; i++){
+		if(ix->arenas[i] != nil && ix->arenas[i]->clumps != 0){
+			hprint(hout, "arena=%s at index [%lld,%lld)\n\t", ix->amap[i].name, ix->amap[i].start, ix->amap[i].stop);
+			darena(hout, ix->arenas[i]);
+		}
+	}
+	hflush(hout);
+	return 0;
+}
+
+static int
+xindex(HConnect *c)
+{
+	Hio *hout;
+	int r;
+
+	r = preq(c);
+	if(r <= 0)
+		return r;
+
+	hout = &c->hout;
+	if(c->req.vermaj){
+		hokheaders(c);
+		hprint(hout, "Content-type: text/xml\r\n");
+		if(http11(c))
+			hprint(hout, "Transfer-Encoding: chunked\r\n");
+		hprint(hout, "\r\n");
+	}
+
+	if(http11(c))
+		hxferenc(hout, 1);
+	else
+		c->head.closeit = 1;
+	xmlindex(hout, mainindex, "index", 0);
+	hflush(hout);
+	return 0;
+}
+
+void
+xmlindent(Hio *hout, int indent)
+{
+	int i;
+
+	for(i = 0; i < indent; i++)
+		hputc(hout, '\t');
+}
+
+void
+xmlaname(Hio *hout, char *v, char *tag)
+{
+	hprint(hout, " %s=\"%s\"", tag, v);
+}
+
+void
+xmlscore(Hio *hout, u8int *v, char *tag)
+{
+	if(scorecmp(zeroscore, v) == 0)
+		return;
+	hprint(hout, " %s=\"%V\"", tag, v);
+}
+
+void
+xmlsealed(Hio *hout, int v, char *tag)
+{
+	if(!v)
+		return;
+	hprint(hout, " %s=\"yes\"", tag);
+}
+
+void
+xmlu32int(Hio *hout, u32int v, char *tag)
+{
+	hprint(hout, " %s=\"%ud\"", tag, v);
+}
+
+void
+xmlu64int(Hio *hout, u64int v, char *tag)
+{
+	hprint(hout, " %s=\"%llud\"", tag, v);
+}
diff --git a/src/cmd/venti/icache.c b/src/cmd/venti/icache.c
new file mode 100644
index 00000000..04f1134e
--- /dev/null
+++ b/src/cmd/venti/icache.c
@@ -0,0 +1,199 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+struct ICache
+{
+	QLock	lock;			/* locks hash table & all associated data */
+	IEntry	**heads;		/* heads of all the hash chains */
+	int	bits;			/* bits to use for indexing heads */
+	u32int	size;			/* number of heads; == 1 << bits, should be < entries */
+	IEntry	*base;			/* all allocated hash table entries */
+	u32int	entries;		/* elements in base */
+	u32int	unused;			/* index of first unused element in base */
+	u32int	stolen;			/* last head from which an element was stolen */
+};
+
+static ICache icache;
+
+static IEntry	*icachealloc(IAddr *ia, u8int *score);
+
+/*
+ * bits is the number of bits in the icache hash table
+ * depth is the average depth
+ * memory usage is about (1<<bits) * depth * sizeof(IEntry) + (1<<bits) * sizeof(IEntry*)
+ */
+void
+initicache(int bits, int depth)
+{
+	icache.bits = bits;
+	icache.size = 1 << bits;
+	icache.entries = depth * icache.size;
+	icache.base = MKNZ(IEntry, icache.entries);
+	icache.heads = MKNZ(IEntry*, icache.size);
+}
+
+u32int
+hashbits(u8int *sc, int bits)
+{
+	u32int v;
+
+	v = (sc[0] << 24) | (sc[1] << 16) | (sc[2] << 8) | sc[3];
+	if(bits < 32)
+		 v >>= (32 - bits);
+	return v;
+}
+
+/*
+ZZZ need to think about evicting the correct IEntry,
+and writing back the wtime.
+ * look up data score in the index cache
+ * if this fails, pull it in from the disk index table, if it exists.
+ *
+ * must be called with the lump for this score locked
+ */
+int
+lookupscore(u8int *score, int type, IAddr *ia, int *rac)
+{
+	IEntry d, *ie, *last;
+	u32int h;
+
+fprint(2, "lookupscore %V %d\n", score, type);
+	qlock(&stats.lock);
+	stats.iclookups++;
+	qunlock(&stats.lock);
+
+	qlock(&icache.lock);
+	h = hashbits(score, icache.bits);
+	last = nil;
+	for(ie = icache.heads[h]; ie != nil; ie = ie->next){
+		if(ie->ia.type == type && scorecmp(ie->score, score)==0){
+			if(last != nil)
+				last->next = ie->next;
+			else
+				icache.heads[h] = ie->next;
+			qlock(&stats.lock);
+			stats.ichits++;
+			qunlock(&stats.lock);
+			ie->rac = 1;
+			goto found;
+		}
+		last = ie;
+	}
+
+	qunlock(&icache.lock);
+
+	if(loadientry(mainindex, score, type, &d) < 0)
+		return -1;
+
+	/*
+	 * no one else can load an entry for this score,
+	 * since we have the overall score lock.
+	 */
+	qlock(&stats.lock);
+	stats.icfills++;
+	qunlock(&stats.lock);
+
+	qlock(&icache.lock);
+
+	ie = icachealloc(&d.ia, score);
+
+found:
+	ie->next = icache.heads[h];
+	icache.heads[h] = ie;
+
+	*ia = ie->ia;
+	*rac = ie->rac;
+
+	qunlock(&icache.lock);
+
+	return 0;
+}
+
+/*
+ * insert a new element in the hash table.
+ */
+int
+insertscore(u8int *score, IAddr *ia, int write)
+{
+	IEntry *ie, se;
+	u32int h;
+
+	qlock(&stats.lock);
+	stats.icinserts++;
+	qunlock(&stats.lock);
+
+	qlock(&icache.lock);
+	h = hashbits(score, icache.bits);
+
+	ie = icachealloc(ia, score);
+
+	ie->next = icache.heads[h];
+	icache.heads[h] = ie;
+
+	se = *ie;
+
+	qunlock(&icache.lock);
+
+	if(!write)
+		return 0;
+
+	return storeientry(mainindex, &se);
+}
+
+/*
+ * allocate a index cache entry which hasn't been used in a while.
+ * must be called with icache.lock locked
+ * if the score is already in the table, update the entry.
+ */
+static IEntry *
+icachealloc(IAddr *ia, u8int *score)
+{
+	IEntry *ie, *last, *next;
+	u32int h;
+
+	h = hashbits(score, icache.bits);
+	last = nil;
+	for(ie = icache.heads[h]; ie != nil; ie = ie->next){
+		if(ie->ia.type == ia->type && scorecmp(ie->score, score)==9){
+			if(last != nil)
+				last->next = ie->next;
+			else
+				icache.heads[h] = ie->next;
+			ie->rac = 1;
+			return ie;
+		}
+		last = ie;
+	}
+
+	h = icache.unused;
+	if(h < icache.entries){
+		ie = &icache.base[h++];
+		icache.unused = h;
+		goto Found;
+	}
+
+	h = icache.stolen;
+	for(;;){
+		h++;
+		if(h >= icache.size)
+			h = 0;
+		ie = icache.heads[h];
+		if(ie != nil){
+			last = nil;
+			for(; next = ie->next; ie = next)
+				last = ie;
+			if(last != nil)
+				last->next = nil;
+			else
+				icache.heads[h] = nil;
+			icache.stolen = h;
+			goto Found;
+		}
+	}
+Found:
+	ie->ia = *ia;
+	scorecp(ie->score, score);
+	ie->rac = 0;	
+	return ie;
+}
diff --git a/src/cmd/venti/ifile.c b/src/cmd/venti/ifile.c
new file mode 100644
index 00000000..811e487c
--- /dev/null
+++ b/src/cmd/venti/ifile.c
@@ -0,0 +1,93 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+int
+readifile(IFile *f, char *name)
+{
+	ZBlock *b;
+
+	b = readfile(name);
+	if(b == nil)
+		return -1;
+	f->name = name;
+	f->b = b;
+	f->pos = 0;
+	return 0;
+}
+
+void
+freeifile(IFile *f)
+{
+	freezblock(f->b);
+	f->b = nil;
+	f->pos = 0;
+}
+
+int
+partifile(IFile *f, Part *part, u64int start, u32int size)
+{
+	ZBlock *b;
+
+	b = alloczblock(size, 0);
+	if(b == nil)
+		return -1;
+	if(readpart(part, start, b->data, size) < 0){
+		seterr(EAdmin, "can't read %s: %r", part->name);
+		freezblock(b);
+		return -1;
+	}
+	f->name = part->name;
+	f->b = b;
+	f->pos = 0;
+	return 0;
+}
+
+/*
+ * return the next non-blank input line,
+ * stripped of leading white space and with # comments eliminated
+ */
+char*
+ifileline(IFile *f)
+{
+	char *s, *e, *t;
+	int c;
+
+	for(;;){
+		s = (char*)&f->b->data[f->pos];
+		e = memchr(s, '\n', f->b->len - f->pos);
+		if(e == nil)
+			return nil;
+		*e++ = '\0';
+		f->pos = e - (char*)f->b->data;
+		t = strchr(s, '#');
+		if(t != nil)
+			*t = '\0';
+		for(; c = *s; s++)
+			if(c != ' ' && c != '\t' && c != '\r')
+				return s;
+	}
+}
+
+int
+ifilename(IFile *f, char *dst)
+{
+	char *s;
+
+	s = ifileline(f);
+	if(s == nil || strlen(s) >= ANameSize)
+		return -1;
+	namecp(dst, s);
+	return 0;
+}
+
+int
+ifileu32int(IFile *f, u32int *r)
+{
+	char *s;
+
+	s = ifileline(f);
+	if(s == nil)
+		return -1;
+	return stru32int(s, r);
+}
diff --git a/src/cmd/venti/index.c b/src/cmd/venti/index.c
new file mode 100644
index 00000000..9d3ad8c4
--- /dev/null
+++ b/src/cmd/venti/index.c
@@ -0,0 +1,790 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+static int	bucklook(u8int *score, int type, u8int *data, int n);
+static int	writebucket(ISect *is, u32int buck, IBucket *ib, DBlock *b);
+static int	okibucket(IBucket *ib, ISect *is);
+static ISect	*initisect1(ISect *is);
+
+//static QLock	indexlock;	//ZZZ
+
+static char IndexMagic[] = "venti index configuration";
+
+Index*
+initindex(char *name, ISect **sects, int n)
+{
+	IFile f;
+	Index *ix;
+	ISect *is;
+	u32int last, blocksize, tabsize;
+	int i;
+
+	if(n <= 0){
+		seterr(EOk, "no index sections to initialize index");
+		return nil;
+	}
+	ix = MKZ(Index);
+	if(ix == nil){
+		seterr(EOk, "can't initialize index: out of memory");
+		freeindex(ix);
+		return nil;
+	}
+
+	tabsize = sects[0]->tabsize;
+	if(partifile(&f, sects[0]->part, sects[0]->tabbase, tabsize) < 0)
+		return nil;
+	if(parseindex(&f, ix) < 0){
+		freeifile(&f);
+		freeindex(ix);
+		return nil;
+	}
+	freeifile(&f);
+	if(namecmp(ix->name, name) != 0){
+		seterr(ECorrupt, "mismatched index name: found %s expected %s", ix->name, name);
+		return nil;
+	}
+	if(ix->nsects != n){
+		seterr(ECorrupt, "mismatched number index sections: found %d expected %d", n, ix->nsects);
+		freeindex(ix);
+		return nil;
+	}
+	ix->sects = sects;
+	last = 0;
+	blocksize = ix->blocksize;
+	for(i = 0; i < ix->nsects; i++){
+		is = sects[i];
+		if(namecmp(ix->name, is->index) != 0
+		|| is->blocksize != blocksize
+		|| is->tabsize != tabsize
+		|| namecmp(is->name, ix->smap[i].name) != 0
+		|| is->start != ix->smap[i].start
+		|| is->stop != ix->smap[i].stop
+		|| last != is->start
+		|| is->start > is->stop){
+			seterr(ECorrupt, "inconsistent index sections in %s", ix->name);
+			freeindex(ix);
+			return nil;
+		}
+		last = is->stop;
+	}
+	ix->tabsize = tabsize;
+	ix->buckets = last;
+
+	ix->div = (((u64int)1 << 32) + last - 1) / last;
+	last = (((u64int)1 << 32) - 1) / ix->div + 1;
+	if(last != ix->buckets){
+		seterr(ECorrupt, "inconsistent math for buckets in %s", ix->name);
+		freeindex(ix);
+		return nil;
+	}
+
+	ix->arenas = MKNZ(Arena*, ix->narenas);
+	if(maparenas(ix->amap, ix->arenas, ix->narenas, ix->name) < 0){
+		freeindex(ix);
+		return nil;
+	}
+	return ix;
+}
+
+int
+wbindex(Index *ix)
+{
+	Fmt f;
+	ZBlock *b;
+	int i;
+
+	if(ix->nsects == 0){
+		seterr(EOk, "no sections in index %s", ix->name);
+		return -1;
+	}
+	b = alloczblock(ix->tabsize, 1);
+	if(b == nil){
+		seterr(EOk, "can't write index configuration: out of memory");
+		return -1;
+	}
+	fmtzbinit(&f, b);
+	if(outputindex(&f, ix) < 0){
+		seterr(EOk, "can't make index configuration: table storage too small %d", ix->tabsize);
+		freezblock(b);
+		return -1;
+	}
+	for(i = 0; i < ix->nsects; i++){
+		if(writepart(ix->sects[i]->part, ix->sects[i]->tabbase, b->data, ix->tabsize) < 0){
+			seterr(EOk, "can't write index: %r");
+			freezblock(b);
+			return -1;
+		}
+	}
+	freezblock(b);
+
+	for(i = 0; i < ix->nsects; i++)
+		if(wbisect(ix->sects[i]) < 0)
+			return -1;
+
+	return 0;
+}
+
+/*
+ * index: IndexMagic '\n' version '\n' name '\n' blocksize '\n' sections arenas
+ * version, blocksize: u32int
+ * name: max. ANameSize string
+ * sections, arenas: AMap
+ */
+int
+outputindex(Fmt *f, Index *ix)
+{
+	if(fmtprint(f, "%s\n%ud\n%s\n%ud\n", IndexMagic, ix->version, ix->name, ix->blocksize) < 0
+	|| outputamap(f, ix->smap, ix->nsects) < 0
+	|| outputamap(f, ix->amap, ix->narenas) < 0)
+		return -1;
+	return 0;
+}
+
+int
+parseindex(IFile *f, Index *ix)
+{
+	AMapN amn;
+	u32int v;
+	char *s;
+
+	/*
+	 * magic
+	 */
+	s = ifileline(f);
+	if(s == nil || strcmp(s, IndexMagic) != 0){
+		seterr(ECorrupt, "bad index magic for %s", f->name);
+		return -1;
+	}
+
+	/*
+	 * version
+	 */
+	if(ifileu32int(f, &v) < 0){
+		seterr(ECorrupt, "syntax error: bad version number in %s", f->name);
+		return -1;
+	}
+	ix->version = v;
+	if(ix->version != IndexVersion){
+		seterr(ECorrupt, "bad version number in %s", f->name);
+		return -1;
+	}
+
+	/*
+	 * name
+	 */
+	if(ifilename(f, ix->name) < 0){
+		seterr(ECorrupt, "syntax error: bad index name in %s", f->name);
+		return -1;
+	}
+
+	/*
+	 * block size
+	 */
+	if(ifileu32int(f, &v) < 0){
+		seterr(ECorrupt, "syntax error: bad version number in %s", f->name);
+		return -1;
+	}
+	ix->blocksize = v;
+
+	if(parseamap(f, &amn) < 0)
+		return -1;
+	ix->nsects = amn.n;
+	ix->smap = amn.map;
+
+	if(parseamap(f, &amn) < 0)
+		return -1;
+	ix->narenas = amn.n;
+	ix->amap = amn.map;
+
+	return 0;
+}
+
+/*
+ * initialize an entirely new index
+ */
+Index *
+newindex(char *name, ISect **sects, int n)
+{
+	Index *ix;
+	AMap *smap;
+	u64int nb;
+	u32int div, ub, xb, start, stop, blocksize, tabsize;
+	int i, j;
+
+	if(n < 1){
+		seterr(EOk, "creating index with no index sections");
+		return nil;
+	}
+
+	/*
+	 * compute the total buckets available in the index,
+	 * and the total buckets which are used.
+	 */
+	nb = 0;
+	blocksize = sects[0]->blocksize;
+	tabsize = sects[0]->tabsize;
+	for(i = 0; i < n; i++){
+		if(sects[i]->start != 0 || sects[i]->stop != 0
+		|| sects[i]->index[0] != '\0'){
+			seterr(EOk, "creating new index using non-empty section %s", sects[i]->name);
+			return nil;
+		}
+		if(blocksize != sects[i]->blocksize){
+			seterr(EOk, "mismatched block sizes in index sections");
+			return nil;
+		}
+		if(tabsize != sects[i]->tabsize){
+			seterr(EOk, "mismatched config table sizes in index sections");
+			return nil;
+		}
+		nb += sects[i]->blocks;
+	}
+
+	/*
+	 * check for duplicate names
+	 */
+	for(i = 0; i < n; i++){
+		for(j = i + 1; j < n; j++){
+			if(namecmp(sects[i]->name, sects[j]->name) == 0){
+				seterr(EOk, "duplicate section name %s for index %s", sects[i]->name, name);
+				return nil;
+			}
+		}
+	}
+
+	if(nb >= ((u64int)1 << 32)){
+		seterr(EBug, "index too large");
+		return nil;
+	}
+	div = (((u64int)1 << 32) + nb - 1) / nb;
+	ub = (((u64int)1 << 32) - 1) / div + 1;
+	if(div < 100){
+		seterr(EBug, "index divisor too coarse");
+		return nil;
+	}
+	if(ub > nb){
+		seterr(EBug, "index initialization math wrong");
+		return nil;
+	}
+
+	/*
+	 * initialize each of the index sections
+	 * and the section map table
+	 */
+	smap = MKNZ(AMap, n);
+	if(smap == nil){
+		seterr(EOk, "can't create new index: out of memory");
+		return nil;
+	}
+	xb = nb - ub;
+	start = 0;
+	for(i = 0; i < n; i++){
+		stop = start + sects[i]->blocks - xb / n;
+		if(i == n - 1)
+			stop = ub;
+		sects[i]->start = start;
+		sects[i]->stop = stop;
+		namecp(sects[i]->index, name);
+
+		smap[i].start = start;
+		smap[i].stop = stop;
+		namecp(smap[i].name, sects[i]->name);
+		start = stop;
+	}
+
+	/*
+	 * initialize the index itself
+	 */
+	ix = MKZ(Index);
+	if(ix == nil){
+		seterr(EOk, "can't create new index: out of memory");
+		free(smap);
+		return nil;
+	}
+	ix->version = IndexVersion;
+	namecp(ix->name, name);
+	ix->sects = sects;
+	ix->smap = smap;
+	ix->nsects = n;
+	ix->blocksize = blocksize;
+	ix->div = div;
+	ix->buckets = ub;
+	ix->tabsize = tabsize;
+	return ix;
+}
+
+ISect*
+initisect(Part *part)
+{
+	ISect *is;
+	ZBlock *b;
+	int ok;
+
+	b = alloczblock(HeadSize, 0);
+	if(b == nil || readpart(part, PartBlank, b->data, HeadSize) < 0){
+		seterr(EAdmin, "can't read index section header: %r");
+		return nil;
+	}
+
+	is = MKZ(ISect);
+	if(is == nil){
+		freezblock(b);
+		return nil;
+	}
+	is->part = part;
+	ok = unpackisect(is, b->data);
+	freezblock(b);
+	if(ok < 0){
+		seterr(ECorrupt, "corrupted index section header: %r");
+		freeisect(is);
+		return nil;
+	}
+
+	if(is->version != ISectVersion){
+		seterr(EAdmin, "unknown index section version %d", is->version);
+		freeisect(is);
+		return nil;
+	}
+
+	return initisect1(is);
+}
+
+ISect*
+newisect(Part *part, char *name, u32int blocksize, u32int tabsize)
+{
+	ISect *is;
+	u32int tabbase;
+
+	is = MKZ(ISect);
+	if(is == nil)
+		return nil;
+
+	namecp(is->name, name);
+	is->version = ISectVersion;
+	is->part = part;
+	is->blocksize = blocksize;
+	is->start = 0;
+	is->stop = 0;
+	tabbase = (PartBlank + HeadSize + blocksize - 1) & ~(blocksize - 1);
+	is->blockbase = (tabbase + tabsize + blocksize - 1) & ~(blocksize - 1);
+	is->blocks = is->part->size / blocksize - is->blockbase / blocksize;
+
+	is = initisect1(is);
+	if(is == nil)
+		return nil;
+
+	return is;
+}
+
+/*
+ * initialize the computed paramaters for an index
+ */
+static ISect*
+initisect1(ISect *is)
+{
+	u64int v;
+
+	is->buckmax = (is->blocksize - IBucketSize) / IEntrySize;
+	is->blocklog = u64log2(is->blocksize);
+	if(is->blocksize != (1 << is->blocklog)){
+		seterr(ECorrupt, "illegal non-power-of-2 bucket size %d\n", is->blocksize);
+		freeisect(is);
+		return nil;
+	}
+	partblocksize(is->part, is->blocksize);
+	is->tabbase = (PartBlank + HeadSize + is->blocksize - 1) & ~(is->blocksize - 1);
+	if(is->tabbase >= is->blockbase){
+		seterr(ECorrupt, "index section config table overlaps bucket storage");
+		freeisect(is);
+		return nil;
+	}
+	is->tabsize = is->blockbase - is->tabbase;
+	v = is->part->size & ~(u64int)(is->blocksize - 1);
+	if(is->blockbase + (u64int)is->blocks * is->blocksize != v){
+		seterr(ECorrupt, "invalid blocks in index section %s", is->name);
+//ZZZZZZZZZ
+//		freeisect(is);
+//		return nil;
+	}
+
+	if(is->stop - is->start > is->blocks){
+		seterr(ECorrupt, "index section overflows available space");
+		freeisect(is);
+		return nil;
+	}
+	if(is->start > is->stop){
+		seterr(ECorrupt, "invalid index section range");
+		freeisect(is);
+		return nil;
+	}
+
+	return is;
+}
+
+int
+wbisect(ISect *is)
+{
+	ZBlock *b;
+
+	b = alloczblock(HeadSize, 1);
+	if(b == nil)
+//ZZZ set error?
+		return -1;
+
+	if(packisect(is, b->data) < 0){
+		seterr(ECorrupt, "can't make index section header: %r");
+		freezblock(b);
+		return -1;
+	}
+	if(writepart(is->part, PartBlank, b->data, HeadSize) < 0){
+		seterr(EAdmin, "can't write index section header: %r");
+		freezblock(b);
+		return -1;
+	}
+	freezblock(b);
+
+	return 0;
+}
+
+void
+freeisect(ISect *is)
+{
+	if(is == nil)
+		return;
+	free(is);
+}
+
+void
+freeindex(Index *ix)
+{
+	int i;
+
+	if(ix == nil)
+		return;
+	free(ix->amap);
+	free(ix->arenas);
+	if(ix->sects)
+		for(i = 0; i < ix->nsects; i++)
+			freeisect(ix->sects[i]);
+	free(ix->sects);
+	free(ix->smap);
+	free(ix);
+}
+
+/*
+ * write a clump to an available arena in the index
+ * and return the address of the clump within the index.
+ZZZ question: should this distinguish between an arena
+filling up and real errors writing the clump?
+ */
+u64int
+writeiclump(Index *ix, Clump *c, u8int *clbuf)
+{
+	u64int a;
+	int i;
+
+	for(i = ix->mapalloc; i < ix->narenas; i++){
+		a = writeaclump(ix->arenas[i], c, clbuf);
+		if(a != TWID64)
+			return a + ix->amap[i].start;
+	}
+
+	seterr(EAdmin, "no space left in arenas");
+	return -1;
+}
+
+/*
+ * convert an arena index to an relative address address
+ */
+Arena*
+amapitoa(Index *ix, u64int a, u64int *aa)
+{
+	int i, r, l, m;
+
+	l = 1;
+	r = ix->narenas - 1;
+	while(l <= r){
+		m = (r + l) / 2;
+		if(ix->amap[m].start <= a)
+			l = m + 1;
+		else
+			r = m - 1;
+	}
+	l--;
+
+	if(a > ix->amap[l].stop){
+for(i=0; i<ix->narenas; i++)
+	print("arena %d: %llux - %llux\n", i, ix->amap[i].start, ix->amap[i].stop);
+print("want arena %d for %llux\n", l, a);
+		seterr(ECrash, "unmapped address passed to amapitoa");
+		return nil;
+	}
+
+	if(ix->arenas[l] == nil){
+		seterr(ECrash, "unmapped arena selected in amapitoa");
+		return nil;
+	}
+	*aa = a - ix->amap[l].start;
+	return ix->arenas[l];
+}
+
+int
+iaddrcmp(IAddr *ia1, IAddr *ia2)
+{
+	return ia1->type != ia2->type
+		|| ia1->size != ia2->size
+		|| ia1->blocks != ia2->blocks
+		|| ia1->addr != ia2->addr;
+}
+
+/*
+ * lookup the score in the partition
+ *
+ * nothing needs to be explicitly locked:
+ * only static parts of ix are used, and
+ * the bucket is locked by the DBlock lock.
+ */
+int
+loadientry(Index *ix, u8int *score, int type, IEntry *ie)
+{
+	ISect *is;
+	DBlock *b;
+	IBucket ib;
+	u32int buck;
+	int h, ok;
+
+fprint(2, "loadientry %V %d\n", score, type);
+	buck = hashbits(score, 32) / ix->div;
+	ok = -1;
+	for(;;){
+		qlock(&stats.lock);
+		stats.indexreads++;
+		qunlock(&stats.lock);
+		is = findisect(ix, buck);
+		if(is == nil){
+			seterr(EAdmin, "bad math in loadientry");
+			return -1;
+		}
+		buck -= is->start;
+		b = getdblock(is->part, is->blockbase + ((u64int)buck << is->blocklog), 1);
+		if(b == nil)
+			break;
+
+		unpackibucket(&ib, b->data);
+		if(okibucket(&ib, is) < 0)
+			break;
+
+		h = bucklook(score, type, ib.data, ib.n);
+		if(h & 1){
+			h ^= 1;
+			unpackientry(ie, &ib.data[h]);
+			ok = 0;
+			break;
+		}
+
+		break;
+	}
+	putdblock(b);
+	return ok;
+}
+
+/*
+ * insert or update an index entry into the appropriate bucket
+ */
+int
+storeientry(Index *ix, IEntry *ie)
+{
+	ISect *is;
+	DBlock *b;
+	IBucket ib;
+	u32int buck;
+	int h, ok;
+
+	buck = hashbits(ie->score, 32) / ix->div;
+	ok = 0;
+	for(;;){
+		qlock(&stats.lock);
+		stats.indexwreads++;
+		qunlock(&stats.lock);
+		is = findisect(ix, buck);
+		if(is == nil){
+			seterr(EAdmin, "bad math in storeientry");
+			return -1;
+		}
+		buck -= is->start;
+		b = getdblock(is->part, is->blockbase + ((u64int)buck << is->blocklog), 1);
+		if(b == nil)
+			break;
+
+		unpackibucket(&ib, b->data);
+		if(okibucket(&ib, is) < 0)
+			break;
+
+		h = bucklook(ie->score, ie->ia.type, ib.data, ib.n);
+		if(h & 1){
+			h ^= 1;
+			packientry(ie, &ib.data[h]);
+			ok = writebucket(is, buck, &ib, b);
+			break;
+		}
+
+		if(ib.n < is->buckmax){
+			memmove(&ib.data[h + IEntrySize], &ib.data[h], ib.n * IEntrySize - h);
+			ib.n++;
+
+			packientry(ie, &ib.data[h]);
+			ok = writebucket(is, buck, &ib, b);
+			break;
+		}
+
+		break;
+	}
+
+	putdblock(b);
+	return ok;
+}
+
+static int
+writebucket(ISect *is, u32int buck, IBucket *ib, DBlock *b)
+{
+	if(buck >= is->blocks)
+		seterr(EAdmin, "index write out of bounds: %d >= %d\n",
+				buck, is->blocks);
+	qlock(&stats.lock);
+	stats.indexwrites++;
+	qunlock(&stats.lock);
+	packibucket(ib, b->data);
+	return writepart(is->part, is->blockbase + ((u64int)buck << is->blocklog), b->data, is->blocksize);
+}
+
+/*
+ * find the number of the index section holding score
+ */
+int
+indexsect(Index *ix, u8int *score)
+{
+	u32int buck;
+	int r, l, m;
+
+	buck = hashbits(score, 32) / ix->div;
+	l = 1;
+	r = ix->nsects - 1;
+	while(l <= r){
+		m = (r + l) >> 1;
+		if(ix->sects[m]->start <= buck)
+			l = m + 1;
+		else
+			r = m - 1;
+	}
+	return l - 1;
+}
+
+/*
+ * find the index section which holds buck
+ */
+ISect*
+findisect(Index *ix, u32int buck)
+{
+	ISect *is;
+	int r, l, m;
+
+	l = 1;
+	r = ix->nsects - 1;
+	while(l <= r){
+		m = (r + l) >> 1;
+		if(ix->sects[m]->start <= buck)
+			l = m + 1;
+		else
+			r = m - 1;
+	}
+	is = ix->sects[l - 1];
+	if(is->start <= buck && is->stop > buck)
+		return is;
+	return nil;
+}
+
+static int
+okibucket(IBucket *ib, ISect *is)
+{
+	if(ib->n <= is->buckmax && (ib->next == 0 || ib->next >= is->start && ib->next < is->stop))
+		return 0;
+
+	seterr(EICorrupt, "corrupted disk index bucket: n=%ud max=%ud, next=%lud range=[%lud,%lud)",
+		ib->n, is->buckmax, ib->next, is->start, is->stop);
+	return -1;
+}
+
+/*
+ * look for score within data;
+ * return 1 | byte index of matching index,
+ * or 0 | index of least element > score
+ */
+static int
+bucklook(u8int *score, int otype, u8int *data, int n)
+{
+	int i, r, l, m, h, c, cc, type;
+
+	type = vttodisktype(otype);
+fprint(2, "bucklook %V %d->%d %d\n", score, otype, type, n);
+	l = 0;
+	r = n - 1;
+	while(l <= r){
+		m = (r + l) >> 1;
+		h = m * IEntrySize;
+fprint(2, "perhaps %V %d\n", data+h, data[h+IEntryTypeOff]);
+		for(i = 0; i < VtScoreSize; i++){
+			c = score[i];
+			cc = data[h + i];
+			if(c != cc){
+				if(c > cc)
+					l = m + 1;
+				else
+					r = m - 1;
+				goto cont;
+			}
+		}
+		cc = data[h + IEntryTypeOff];
+		if(type != cc){
+			if(type > cc)
+				l = m + 1;
+			else
+				r = m - 1;
+			goto cont;
+		}
+		return h | 1;
+	cont:;
+	}
+
+	return l * IEntrySize;
+}
+
+/*
+ * compare two IEntries; consistent with bucklook
+ */
+int
+ientrycmp(const void *vie1, const void *vie2)
+{
+	u8int *ie1, *ie2;
+	int i, v1, v2;
+
+	ie1 = (u8int*)vie1;
+	ie2 = (u8int*)vie2;
+	for(i = 0; i < VtScoreSize; i++){
+		v1 = ie1[i];
+		v2 = ie2[i];
+		if(v1 != v2){
+			if(v1 < v2)
+				return -1;
+			return 0;
+		}
+	}
+	v1 = ie1[IEntryTypeOff];
+	v2 = ie2[IEntryTypeOff];
+	if(v1 != v2){
+		if(v1 < v2)
+			return -1;
+		return 0;
+	}
+	return -1;
+}
diff --git a/src/cmd/venti/lump.c b/src/cmd/venti/lump.c
new file mode 100644
index 00000000..c449f022
--- /dev/null
+++ b/src/cmd/venti/lump.c
@@ -0,0 +1,206 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+int			queuewrites = 0;
+
+static Packet		*readilump(Lump *u, IAddr *ia, u8int *score, int rac);
+
+Packet*
+readlump(u8int *score, int type, u32int size)
+{
+	Lump *u;
+	Packet *p;
+	IAddr ia;
+	u32int n;
+	int rac;
+
+	qlock(&stats.lock);
+	stats.lumpreads++;
+	qunlock(&stats.lock);
+	u = lookuplump(score, type);
+	if(u->data != nil){
+		n = packetsize(u->data);
+		if(n > size){
+			seterr(EOk, "read too small: asked for %d need at least %d", size, n);
+			putlump(u);
+
+			return nil;
+		}
+		p = packetdup(u->data, 0, n);
+		putlump(u);
+
+		return p;
+	}
+
+	if(lookupscore(score, type, &ia, &rac) < 0){
+		//ZZZ place to check for someone trying to guess scores
+		seterr(EOk, "no block with that score exists");
+
+		putlump(u);
+		return nil;
+	}
+	if(ia.size > size){
+		seterr(EOk, "read too small 1: asked for %d need at least %d", size, ia.size);
+
+		putlump(u);
+		return nil;
+	}
+
+	p = readilump(u, &ia, score, rac);
+	putlump(u);
+
+	return p;
+}
+
+/*
+ * save away a lump, and return it's score.
+ * doesn't store duplicates, but checks that the data is really the same.
+ */
+int
+writelump(Packet *p, u8int *score, int type, u32int creator)
+{
+	Lump *u;
+	int ok;
+
+	qlock(&stats.lock);
+	stats.lumpwrites++;
+	qunlock(&stats.lock);
+
+	packetsha1(p, score);
+
+	u = lookuplump(score, type);
+	if(u->data != nil){
+		ok = 0;
+		if(packetcmp(p, u->data) != 0){
+			seterr(EStrange, "score collision");
+			ok = -1;
+		}
+		packetfree(p);
+		putlump(u);
+		return ok;
+	}
+
+print("writelump %08x\n", mainindex->arenas[0]);
+	if(queuewrites)
+		return queuewrite(u, p, creator);
+
+	ok = writeqlump(u, p, creator);
+
+	putlump(u);
+	return ok;
+}
+
+int
+writeqlump(Lump *u, Packet *p, int creator)
+{
+	ZBlock *flat;
+	Packet *old;
+	IAddr ia;
+	int ok;
+	int rac;
+
+	if(lookupscore(u->score, u->type, &ia, &rac) == 0){
+		/*
+		 * if the read fails,
+		 * assume it was corrupted data and store the block again
+		 */
+		old = readilump(u, &ia, u->score, rac);
+		if(old != nil){
+			ok = 0;
+			if(packetcmp(p, old) != 0){
+				seterr(EStrange, "score collision");
+				ok = -1;
+			}
+			packetfree(p);
+			packetfree(old);
+
+			return ok;
+		}
+		logerr(EAdmin, "writelump: read %V failed, rewriting: %r\n", u->score);
+	}
+
+	flat = packet2zblock(p, packetsize(p));
+	ok = storeclump(mainindex, flat, u->score, u->type, creator, &ia);
+	freezblock(flat);
+	if(ok == 0)
+		ok = insertscore(u->score, &ia, 1);
+	if(ok == 0)
+		insertlump(u, p);
+	else
+		packetfree(p);
+
+	return ok;
+}
+
+static void
+readahead(u64int a, Arena *arena, u64int aa, int n)
+{	
+	u8int buf[ClumpSize];
+	Clump cl;
+	IAddr ia;
+
+	while(n > 0) {
+		if (aa >= arena->used)
+			break;
+		if(readarena(arena, aa, buf, ClumpSize) < ClumpSize)
+			break;
+		if(unpackclump(&cl, buf) < 0)
+			break;
+		ia.addr = a;
+		ia.type = cl.info.type;
+		ia.size = cl.info.uncsize;
+		ia.blocks = (cl.info.size + ClumpSize + (1 << ABlockLog) - 1) >> ABlockLog;
+		insertscore(cl.info.score, &ia, 0);
+		a += ClumpSize + cl.info.size;
+		aa += ClumpSize + cl.info.size;
+		n--;
+	}
+}
+
+static Packet*
+readilump(Lump *u, IAddr *ia, u8int *score, int rac)
+{
+	Arena *arena;
+	ZBlock *zb;
+	Packet *p, *pp;
+	Clump cl;
+	u64int a, aa;
+	u8int sc[VtScoreSize];
+
+	arena = amapitoa(mainindex, ia->addr, &aa);
+	if(arena == nil)
+		return nil;
+
+	zb = loadclump(arena, aa, ia->blocks, &cl, sc, paranoid);
+	if(zb == nil)
+		return nil;
+
+	if(ia->size != cl.info.uncsize){
+		seterr(EInconsist, "index and clump size mismatch");
+		freezblock(zb);
+		return nil;
+	}
+	if(ia->type != cl.info.type){
+		seterr(EInconsist, "index and clump type mismatch");
+		freezblock(zb);
+		return nil;
+	}
+	if(scorecmp(score, sc) != 0){
+		seterr(ECrash, "score mismatch");
+		freezblock(zb);
+		return nil;
+	}
+
+	if(rac == 0) {
+		a = ia->addr + ClumpSize + cl.info.size;
+		aa += ClumpSize + cl.info.size;
+		readahead(a, arena, aa, 20);
+	}
+
+	p = zblock2packet(zb, cl.info.uncsize);
+	freezblock(zb);
+	pp = packetdup(p, 0, packetsize(p));
+	insertlump(u, pp);
+	return p;
+}
diff --git a/src/cmd/venti/lumpcache.c b/src/cmd/venti/lumpcache.c
new file mode 100644
index 00000000..979271af
--- /dev/null
+++ b/src/cmd/venti/lumpcache.c
@@ -0,0 +1,380 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+typedef struct LumpCache	LumpCache;
+
+enum
+{
+	HashLog		= 9,
+	HashSize	= 1<<HashLog,
+	HashMask	= HashSize - 1,
+};
+
+struct LumpCache
+{
+	QLock		lock;
+	Rendez		full;
+	Lump		*free;			/* list of available lumps */
+	u32int		allowed;		/* total allowable space for packets */
+	u32int		avail;			/* remaining space for packets */
+	u32int		now;			/* ticks for usage timestamps */
+	Lump		**heads;		/* hash table for finding address */
+	int		nheap;			/* number of available victims */
+	Lump		**heap;			/* heap for locating victims */
+	int		nblocks;		/* number of blocks allocated */
+	Lump		*blocks;		/* array of block descriptors */
+};
+
+static LumpCache	lumpcache;
+
+static void	delheap(Lump *db);
+static int	downheap(int i, Lump *b);
+static void	fixheap(int i, Lump *b);
+static int	upheap(int i, Lump *b);
+static Lump	*bumplump(void);
+
+void
+initlumpcache(u32int size, u32int nblocks)
+{
+	Lump *last, *b;
+	int i;
+
+	lumpcache.full.l = &lumpcache.lock;
+	lumpcache.nblocks = nblocks;
+	lumpcache.allowed = size;
+	lumpcache.avail = size;
+	lumpcache.heads = MKNZ(Lump*, HashSize);
+	lumpcache.heap = MKNZ(Lump*, nblocks);
+	lumpcache.blocks = MKNZ(Lump, nblocks);
+
+	last = nil;
+	for(i = 0; i < nblocks; i++){
+		b = &lumpcache.blocks[i];
+		b->type = TWID8;
+		b->heap = TWID32;
+		b->next = last;
+		last = b;
+	}
+	lumpcache.free = last;
+	lumpcache.nheap = 0;
+}
+
+Lump*
+lookuplump(u8int *score, int type)
+{
+	Lump *b;
+	u32int h;
+
+	h = hashbits(score, HashLog);
+
+	/*
+	 * look for the block in the cache
+	 */
+//checklumpcache();
+	qlock(&lumpcache.lock);
+again:
+	for(b = lumpcache.heads[h]; b != nil; b = b->next){
+		if(scorecmp(score, b->score)==0 && type == b->type){
+			qlock(&stats.lock);
+			stats.lumphit++;
+			qunlock(&stats.lock);
+			goto found;
+		}
+	}
+
+	/*
+	 * missed: locate the block with the oldest second to last use.
+	 * remove it from the heap, and fix up the heap.
+	 */
+	while(lumpcache.free == nil){
+		if(bumplump() == nil){
+			logerr(EAdmin, "all lump cache blocks in use");
+			rsleep(&lumpcache.full);
+			goto again;
+		}
+	}
+	qlock(&stats.lock);
+	stats.lumpmiss++;
+	qunlock(&stats.lock);
+
+	b = lumpcache.free;
+	lumpcache.free = b->next;
+
+	/*
+	 * the new block has no last use, so assume it happens sometime in the middle
+ZZZ this is not reasonable
+	 */
+	b->used = (b->used2 + lumpcache.now) / 2;
+
+	/*
+	 * rechain the block on the correct hash chain
+	 */
+	b->next = lumpcache.heads[h];
+	lumpcache.heads[h] = b;
+	if(b->next != nil)
+		b->next->prev = b;
+	b->prev = nil;
+
+	scorecp(b->score, score);
+	b->type = type;
+	b->size = 0;
+	b->data = nil;
+
+found:
+	b->ref++;
+	b->used2 = b->used;
+	b->used = lumpcache.now++;
+	if(b->heap != TWID32)
+		fixheap(b->heap, b);
+	qunlock(&lumpcache.lock);
+
+//checklumpcache();
+
+	qlock(&b->lock);
+
+	return b;
+}
+
+void
+insertlump(Lump *b, Packet *p)
+{
+	u32int size;
+
+	/*
+	 * look for the block in the cache
+	 */
+//checklumpcache();
+	qlock(&lumpcache.lock);
+again:
+
+	/*
+	 * missed: locate the block with the oldest second to last use.
+	 * remove it from the heap, and fix up the heap.
+	 */
+	size = packetasize(p);
+//ZZZ
+	while(lumpcache.avail < size){
+		if(bumplump() == nil){
+			logerr(EAdmin, "all lump cache blocks in use");
+			rsleep(&lumpcache.full);
+			goto again;
+		}
+	}
+	b->data = p;
+	b->size = size;
+	lumpcache.avail -= size;
+
+	qunlock(&lumpcache.lock);
+//checklumpcache();
+}
+
+void
+putlump(Lump *b)
+{
+	if(b == nil)
+		return;
+
+	qunlock(&b->lock);
+//checklumpcache();
+	qlock(&lumpcache.lock);
+	if(--b->ref == 0){
+		if(b->heap == TWID32)
+			upheap(lumpcache.nheap++, b);
+		rwakeup(&lumpcache.full);
+	}
+
+	qunlock(&lumpcache.lock);
+//checklumpcache();
+}
+
+/*
+ * remove some lump from use and update the free list and counters
+ */
+static Lump*
+bumplump(void)
+{
+	Lump *b;
+	u32int h;
+
+	/*
+	 * remove blocks until we find one that is unused
+	 * referenced blocks are left in the heap even though
+	 * they can't be scavenged; this is simple a speed optimization
+	 */
+	for(;;){
+		if(lumpcache.nheap == 0)
+			return nil;
+		b = lumpcache.heap[0];
+		delheap(b);
+		if(!b->ref){
+			rwakeup(&lumpcache.full);
+			break;
+		}
+	}
+
+	/*
+	 * unchain the block
+	 */
+	if(b->prev == nil){
+		h = hashbits(b->score, HashLog);
+		if(lumpcache.heads[h] != b)
+			sysfatal("bad hash chains in lump cache");
+		lumpcache.heads[h] = b->next;
+	}else
+		b->prev->next = b->next;
+	if(b->next != nil)
+		b->next->prev = b->prev;
+
+	if(b->data != nil){
+		packetfree(b->data);
+		b->data = nil;
+		lumpcache.avail += b->size;
+		b->size = 0;
+	}
+	b->type = TWID8;
+
+	b->next = lumpcache.free;
+	lumpcache.free = b;
+
+	return b;
+}
+
+/*
+ * delete an arbitrary block from the heap
+ */
+static void
+delheap(Lump *db)
+{
+	fixheap(db->heap, lumpcache.heap[--lumpcache.nheap]);
+	db->heap = TWID32;
+}
+
+/*
+ * push an element up or down to it's correct new location
+ */
+static void
+fixheap(int i, Lump *b)
+{
+	if(upheap(i, b) == i)
+		downheap(i, b);
+}
+
+static int
+upheap(int i, Lump *b)
+{
+	Lump *bb;
+	u32int now;
+	int p;
+
+	now = lumpcache.now;
+	for(; i != 0; i = p){
+		p = (i - 1) >> 1;
+		bb = lumpcache.heap[p];
+		if(b->used2 - now >= bb->used2 - now)
+			break;
+		lumpcache.heap[i] = bb;
+		bb->heap = i;
+	}
+
+	lumpcache.heap[i] = b;
+	b->heap = i;
+	return i;
+}
+
+static int
+downheap(int i, Lump *b)
+{
+	Lump *bb;
+	u32int now;
+	int k;
+
+	now = lumpcache.now;
+	for(; ; i = k){
+		k = (i << 1) + 1;
+		if(k >= lumpcache.nheap)
+			break;
+		if(k + 1 < lumpcache.nheap && lumpcache.heap[k]->used2 - now > lumpcache.heap[k + 1]->used2 - now)
+			k++;
+		bb = lumpcache.heap[k];
+		if(b->used2 - now <= bb->used2 - now)
+			break;
+		lumpcache.heap[i] = bb;
+		bb->heap = i;
+	}
+
+	lumpcache.heap[i] = b;
+	b->heap = i;
+	return i;
+}
+
+static void
+findblock(Lump *bb)
+{
+	Lump *b, *last;
+	int h;
+
+	last = nil;
+	h = hashbits(bb->score, HashLog);
+	for(b = lumpcache.heads[h]; b != nil; b = b->next){
+		if(last != b->prev)
+			sysfatal("bad prev link");
+		if(b == bb)
+			return;
+		last = b;
+	}
+	sysfatal("block score=%V type=%#x missing from hash table", bb->score, bb->type);
+}
+
+void
+checklumpcache(void)
+{
+	Lump *b;
+	u32int size, now, nfree;
+	int i, k, refed;
+
+	qlock(&lumpcache.lock);
+	now = lumpcache.now;
+	for(i = 0; i < lumpcache.nheap; i++){
+		if(lumpcache.heap[i]->heap != i)
+			sysfatal("lc: mis-heaped at %d: %d", i, lumpcache.heap[i]->heap);
+		if(i > 0 && lumpcache.heap[(i - 1) >> 1]->used2 - now > lumpcache.heap[i]->used2 - now)
+			sysfatal("lc: bad heap ordering");
+		k = (i << 1) + 1;
+		if(k < lumpcache.nheap && lumpcache.heap[i]->used2 - now > lumpcache.heap[k]->used2 - now)
+			sysfatal("lc: bad heap ordering");
+		k++;
+		if(k < lumpcache.nheap && lumpcache.heap[i]->used2 - now > lumpcache.heap[k]->used2 - now)
+			sysfatal("lc: bad heap ordering");
+	}
+
+	refed = 0;
+	size = 0;
+	for(i = 0; i < lumpcache.nblocks; i++){
+		b = &lumpcache.blocks[i];
+		if(b->data == nil && b->size != 0)
+			sysfatal("bad size: %d data=%p", b->size, b->data);
+		if(b->ref && b->heap == TWID32)
+			refed++;
+		if(b->type != TWID8){
+			findblock(b);
+			size += b->size;
+		}
+		if(b->heap != TWID32
+		&& lumpcache.heap[b->heap] != b)
+			sysfatal("lc: spurious heap value");
+	}
+	if(lumpcache.avail != lumpcache.allowed - size)
+		sysfatal("mismatched available=%d and allowed=%d - used=%d space", lumpcache.avail, lumpcache.allowed, size);
+
+	nfree = 0;
+	for(b = lumpcache.free; b != nil; b = b->next){
+		if(b->type != TWID8 || b->heap != TWID32)
+			sysfatal("lc: bad free list");
+		nfree++;
+	}
+
+	if(lumpcache.nheap + nfree + refed != lumpcache.nblocks)
+		sysfatal("lc: missing blocks: %d %d %d %d", lumpcache.nheap, refed, nfree, lumpcache.nblocks);
+	qunlock(&lumpcache.lock);
+}
diff --git a/src/cmd/venti/lumpqueue.c b/src/cmd/venti/lumpqueue.c
new file mode 100644
index 00000000..450c7271
--- /dev/null
+++ b/src/cmd/venti/lumpqueue.c
@@ -0,0 +1,150 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+typedef struct LumpQueue	LumpQueue;
+typedef struct WLump		WLump;
+
+enum
+{
+	MaxLumpQ	= 1 << 3	/* max. lumps on a single write queue, must be pow 2 */
+};
+
+struct WLump
+{
+	Lump	*u;
+	Packet	*p;
+	int	creator;
+	int	gen;
+};
+
+struct LumpQueue
+{
+	QLock	lock;
+	Rendez 	flush;
+	Rendez	full;
+	Rendez	empty;
+	WLump	q[MaxLumpQ];
+	int	w;
+	int	r;
+};
+
+static LumpQueue	*lumpqs;
+static int		nqs;
+
+static QLock		glk;
+static int		gen;
+
+static void	queueproc(void *vq);
+
+int
+initlumpqueues(int nq)
+{
+	LumpQueue *q;
+
+	int i;
+	nqs = nq;
+
+	lumpqs = MKNZ(LumpQueue, nq);
+
+	for(i = 0; i < nq; i++){
+		q = &lumpqs[i];
+		q->full.l = &q->lock;
+		q->empty.l = &q->lock;
+		q->flush.l = &q->lock;
+
+		if(vtproc(queueproc, q) < 0){
+			seterr(EOk, "can't start write queue slave: %r");
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * queue a lump & it's packet data for writing
+ */
+int
+queuewrite(Lump *u, Packet *p, int creator)
+{
+	LumpQueue *q;
+	int i;
+
+	i = indexsect(mainindex, u->score);
+	if(i < 0 || i >= nqs){
+		seterr(EBug, "internal error: illegal index section in queuewrite");
+		return -1;
+	}
+
+	q = &lumpqs[i];
+
+	qlock(&q->lock);
+	while(q->r == ((q->w + 1) & (MaxLumpQ - 1)))
+		rsleep(&q->full);
+
+	q->q[q->w].u = u;
+	q->q[q->w].p = p;
+	q->q[q->w].creator = creator;
+	q->q[q->w].gen = gen;
+	q->w = (q->w + 1) & (MaxLumpQ - 1);
+
+	rwakeup(&q->empty);
+
+	qunlock(&q->lock);
+
+	return 0;
+}
+
+void
+queueflush(void)
+{
+	int i;
+	LumpQueue *q;
+
+	qlock(&glk);
+	gen++;
+	qunlock(&glk);
+
+	for(i=0; i<mainindex->nsects; i++){
+		q = &lumpqs[i];
+		qlock(&q->lock);
+		while(q->w != q->r && gen - q->q[q->r].gen > 0)
+			rsleep(&q->flush);
+		qunlock(&q->lock);
+	}
+}
+		
+static void
+queueproc(void *vq)
+{
+	LumpQueue *q;
+	Lump *u;
+	Packet *p;
+	int creator;
+
+	q = vq;
+	for(;;){
+		qlock(&q->lock);
+		while(q->w == q->r)
+			rsleep(&q->empty);
+
+		u = q->q[q->r].u;
+		p = q->q[q->r].p;
+		creator = q->q[q->r].creator;
+
+		rwakeup(&q->full);
+
+		qunlock(&q->lock);
+
+		if(writeqlump(u, p, creator) < 0)
+			fprint(2, "failed to write lump for %V: %r", u->score);
+
+		qlock(&q->lock);
+		q->r = (q->r + 1) & (MaxLumpQ - 1);
+		rwakeup(&q->flush);
+		qunlock(&q->lock);
+
+		putlump(u);
+	}
+}
diff --git a/src/cmd/venti/mkfile b/src/cmd/venti/mkfile
new file mode 100644
index 00000000..48f2c60f
--- /dev/null
+++ b/src/cmd/venti/mkfile
@@ -0,0 +1,89 @@
+PLAN9=../../..
+<$PLAN9/src/mkhdr
+
+LIBOFILES=\
+	arena.$O\
+	arenas.$O\
+	buildbuck.$O\
+	clump.$O\
+	config.$O\
+	conv.$O\
+	dcache.$O\
+	dump.$O\
+	httpd.$O\
+	icache.$O\
+	ifile.$O\
+	index.$O\
+	lump.$O\
+	lumpcache.$O\
+	lumpqueue.$O\
+	part.$O\
+	score.$O\
+	sortientry.$O\
+	stats.$O\
+	syncarena.$O\
+	syncindex0.$O\
+	unwhack.$O\
+	utils.$O\
+	unittoull.$O\
+	whack.$O\
+	xml.$O\
+	zeropart.$O\
+
+SLIB=libvs.a
+
+LIB=$SLIB\
+	$PLAN9/lib/libventi.a\
+	$PLAN9/lib/libhttpd.a\
+	$PLAN9/lib/libbin.a\
+	$PLAN9/lib/libsec.a\
+	$PLAN9/lib/libthread.a\
+	$PLAN9/lib/lib9.a\
+	$PLAN9/lib/libfmt.a\
+	$PLAN9/lib/libutf.a\
+
+HFILES=	dat.h\
+	fns.h\
+	stdinc.h\
+
+TARG=\
+#	venti\
+	fmtarenas\
+	fmtisect\
+	fmtindex\
+	buildindex\
+	checkarenas\
+	checkindex\
+	clumpstats\
+	findscore\
+	rdarena\
+	wrarena\
+	syncindex\
+	verifyarena\
+	sync\
+	read\
+	write\
+	copy\
+
+BIN=$BIN/venti
+
+it:V: all
+
+<$PLAN9/src/mkmany
+
+# xml.c:D:	mkxml dat.h
+# 	./mkxml dat.h > xml.c
+
+$SLIB(%.$O):N: %.$O
+$SLIB:	${LIBOFILES:%=$SLIB(%)}
+	names=`echo $newprereq | sed -E 's/'$SLIB'\(([^)]+)\)/\1/g'`
+	# names = `{echo $newprereq |sed 's/ /\n/g' |sed -n 's/'$SLIB'\(([^)]+)\)/\1/gp'}
+	ar rvc $SLIB $names
+#	rm $names
+
+ainstall:V: ${TARG:%=%.ainstall}
+
+%.ainstall:V:	$O.%
+	scp $prereq amsterdam:/usr/local/bin/venti/$stem
+
+LDFLAGS=$LDFLAGS -l9
diff --git a/src/cmd/venti/mkroot.c b/src/cmd/venti/mkroot.c
new file mode 100644
index 00000000..67e5d0e9
--- /dev/null
+++ b/src/cmd/venti/mkroot.c
@@ -0,0 +1,59 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+char *host;
+
+void
+usage(void)
+{
+	fprint(2, "usage: mkroot [-h host] name type score blocksize prev\n");
+	threadexitsall("usage");
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	uchar score[VtScoreSize];
+	uchar buf[VtRootSize];
+	VtConn *z;
+	VtRoot root;
+
+	ARGBEGIN{
+	case 'h':
+		host = EARGF(usage());
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	if(argc != 5)
+		usage();
+
+	fmtinstall('V', vtscorefmt);
+
+	strecpy(root.name, root.name+sizeof root.name, argv[0]);
+	strecpy(root.type, root.type+sizeof root.type, argv[1]);
+	if(vtparsescore(argv[2], strlen(argv[2]), nil, root.score) < 0)
+		sysfatal("bad score '%s'", argv[2]);
+	root.blocksize = atoi(argv[3]);
+	if(vtparsescore(argv[4], strlen(argv[4]), nil, root.prev) < 0)
+		sysfatal("bad score '%s'", argv[4]);
+	vtrootpack(&root, buf);
+
+	z = vtdial(host);
+	if(z == nil)
+		sysfatal("could not connect to server: %r");
+
+	if(vtconnect(z) < 0)
+		sysfatal("vtconnect: %r");
+
+	if(vtwrite(z, score, VtRootType, buf, VtRootSize) < 0)
+		sysfatal("vtwrite: %r");
+	if(vtsync(z) < 0)
+		sysfatal("vtsync: %r");
+	vthangup(z);
+	print("%V\n", score);
+	threadexitsall(0);
+}
diff --git a/src/cmd/venti/part.c b/src/cmd/venti/part.c
new file mode 100644
index 00000000..dbf7b860
--- /dev/null
+++ b/src/cmd/venti/part.c
@@ -0,0 +1,130 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+u32int	maxblocksize;
+int	readonly;
+
+Part*
+initpart(char *name, int writable)
+{
+	Part *part;
+	Dir *dir;
+	int how;
+
+	part = MK(Part);
+	part->name = estrdup(name);
+	if(!writable && readonly)
+		how = OREAD;
+	else
+		how = ORDWR;
+	part->fd = open(name, how);
+	if(part->fd < 0){
+		if(how == ORDWR)
+			part->fd = open(name, OREAD);
+		if(part->fd < 0){
+			freepart(part);
+			seterr(EOk, "can't open partition='%s': %r", name);
+			return nil;
+		}
+		fprint(2, "warning: %s opened for reading only\n", name);
+	}
+	dir = dirfstat(part->fd);
+	if(dir == nil){
+		freepart(part);
+		seterr(EOk, "can't stat partition='%s': %r", name);
+		return nil;
+	}
+	part->size = dir->length;
+	part->blocksize = 0;
+	free(dir);
+	return part;
+}
+
+void
+freepart(Part *part)
+{
+	if(part == nil)
+		return;
+	close(part->fd);
+	free(part->name);
+	free(part);
+}
+
+void
+partblocksize(Part *part, u32int blocksize)
+{
+	if(part->blocksize)
+		sysfatal("resetting partition=%s's block size", part->name);
+	part->blocksize = blocksize;
+	if(blocksize > maxblocksize)
+		maxblocksize = blocksize;
+}
+
+int
+writepart(Part *part, u64int addr, u8int *buf, u32int n)
+{
+	long m, mm, nn;
+
+	qlock(&stats.lock);
+	stats.diskwrites++;
+	stats.diskbwrites += n;
+	qunlock(&stats.lock);
+
+	if(addr > part->size || addr + n > part->size){
+		seterr(ECorrupt, "out of bounds write to partition='%s'", part->name);
+		return -1;
+	}
+	print("write %s %lud at %llud\n", part->name, n, addr);
+	for(nn = 0; nn < n; nn += m){
+		mm = n - nn;
+		if(mm > MaxIo)
+			mm = MaxIo;
+		m = pwrite(part->fd, &buf[nn], mm, addr + nn);
+		if(m != mm){
+			if(m < 0){
+				seterr(EOk, "can't write partition='%s': %r", part->name);
+				return -1;
+			}
+			logerr(EOk, "truncated write to partition='%s' n=%ld wrote=%ld", part->name, mm, m);
+		}
+	}
+	return 0;
+}
+
+int
+readpart(Part *part, u64int addr, u8int *buf, u32int n)
+{
+	long m, mm, nn;
+	int i;
+
+	qlock(&stats.lock);
+	stats.diskreads++;
+	stats.diskbreads += n;
+	qunlock(&stats.lock);
+
+	if(addr > part->size || addr + n > part->size){
+		seterr(ECorrupt, "out of bounds read from partition='%s': addr=%lld n=%d size=%lld", part->name, addr, n, part->size);
+		return -1;
+	}
+	print("read %s %lud at %llud\n", part->name, n, addr);
+	for(nn = 0; nn < n; nn += m){
+		mm = n - nn;
+		if(mm > MaxIo)
+			mm = MaxIo;
+		m = -1;
+		for(i=0; i<4; i++) {
+			m = pread(part->fd, &buf[nn], mm, addr + nn);
+			if(m == mm)
+				break;
+		}
+		if(m != mm){
+			if(m < 0){
+				seterr(EOk, "can't read partition='%s': %r", part->name);
+				return -1;
+			}
+			logerr(EOk, "warning: truncated read from partition='%s' n=%ld read=%ld", part->name, mm, m);
+		}
+	}
+	return 0;
+}
diff --git a/src/cmd/venti/printarena.c b/src/cmd/venti/printarena.c
new file mode 100644
index 00000000..95121a9f
--- /dev/null
+++ b/src/cmd/venti/printarena.c
@@ -0,0 +1,128 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+int readonly = 1;	/* for part.c */
+
+void
+usage(void)
+{
+	fprint(2, "usage: printarena arenafile [offset]\n");
+	threadexitsall("usage");
+}
+
+static void
+rdarena(Arena *arena, u64int offset)
+{
+	u64int a, aa, e;
+	u32int magic;
+	Clump cl;
+	uchar score[VtScoreSize];
+	ZBlock *lump;
+
+	printarena(2, arena);
+
+	a = arena->base;
+	e = arena->base + arena->size;
+	if(offset != ~(u64int)0) {
+		if(offset >= e-a)
+			sysfatal("bad offset %llud >= %llud\n",
+				offset, e-a);
+		aa = offset;
+	} else
+		aa = 0;
+
+	for(; aa < e; aa += ClumpSize+cl.info.size) {
+		magic = clumpmagic(arena, aa);
+		if(magic == ClumpFreeMagic)
+			break;
+		if(magic != ClumpMagic) {
+			fprint(2, "illegal clump magic number %#8.8ux offset %llud\n",
+				magic, aa);
+			break;
+		}
+		lump = loadclump(arena, aa, 0, &cl, score, 0);
+		if(lump == nil) {
+			fprint(2, "clump %llud failed to read: %r\n", aa);
+			break;
+		}
+		if(cl.info.type != VtTypeCorrupt) {
+			scoremem(score, lump->data, cl.info.uncsize);
+			if(scorecmp(cl.info.score, score) != 0) {
+				fprint(2, "clump %llud has mismatched score\n", aa);
+				break;
+			}
+			if(vttypevalid(cl.info.type) < 0) {
+				fprint(2, "clump %llud has bad type %d\n", aa, cl.info.type);
+				break;
+			}
+		}
+		print("%llud %V %d %d\n", aa, score, cl.info.type, cl.info.uncsize);
+		freezblock(lump);
+	}
+	print("end offset %llud\n", aa);
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	char *file;
+	Arena *arena;
+	u64int offset, aoffset;
+	Part *part;
+	Dir *d;
+	uchar buf[8192];
+	ArenaHead head;
+
+	aoffset = 0;
+	ARGBEGIN{
+	case 'o':
+		aoffset = strtoull(EARGF(usage()), 0, 0);
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	offset = ~(u64int)0;
+	switch(argc) {
+	default:
+		usage();
+	case 2:
+		offset = strtoull(argv[1], 0, 0);
+		/* fall through */
+	case 1:
+		file = argv[0];
+	}
+
+
+	fmtinstall('V', vtscorefmt);
+
+	statsinit();
+
+	if((d = dirstat(file)) == nil)
+		sysfatal("can't stat file %s: %r", file);
+
+	part = initpart(file, 0);
+	if(part == nil)
+		sysfatal("can't open file %s: %r", file);
+	if(readpart(part, aoffset, buf, sizeof buf) < 0)
+		sysfatal("can't read file %s: %r", file);
+
+	if(unpackarenahead(&head, buf) < 0)
+		sysfatal("corrupted arena header: %r");
+
+	if(aoffset+head.size > d->length)
+		sysfatal("arena is truncated: want %llud bytes have %llud\n",
+			head.size, d->length);
+
+	partblocksize(part, head.blocksize);
+	initdcache(8 * MaxDiskBlock);
+
+	arena = initarena(part, aoffset, head.size, head.blocksize);
+	if(arena == nil)
+		sysfatal("initarena: %r");
+
+	rdarena(arena, offset);
+	threadexitsall(0);
+}
diff --git a/src/cmd/venti/rdarena.c b/src/cmd/venti/rdarena.c
new file mode 100644
index 00000000..8d130def
--- /dev/null
+++ b/src/cmd/venti/rdarena.c
@@ -0,0 +1,91 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+static int	verbose;
+
+void
+usage(void)
+{
+	fprint(2, "usage: rdarena [-v] arenapart arena\n");
+	threadexitsall(0);
+}
+
+static void
+rdarena(Arena *arena)
+{
+	ZBlock *b;
+	u64int a, e;
+	u32int bs;
+
+	fprint(2, "copying %s to standard output\n", arena->name);
+	printarena(2, arena);
+
+	bs = MaxIoSize;
+	if(bs < arena->blocksize)
+		bs = arena->blocksize;
+
+	b = alloczblock(bs, 0);
+	e = arena->base + arena->size + arena->blocksize;
+	for(a = arena->base - arena->blocksize; a + arena->blocksize <= e; a += bs){
+		if(a + bs > e)
+			bs = arena->blocksize;
+		if(readpart(arena->part, a, b->data, bs) < 0)
+			fprint(2, "can't copy %s, read at %lld failed: %r\n", arena->name, a);	
+		if(write(1, b->data, bs) != bs)
+			sysfatal("can't copy %s, write at %lld failed: %r", arena->name, a);
+	}
+
+	freezblock(b);
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	ArenaPart *ap;
+	Part *part;
+	char *file, *aname;
+	int i;
+
+	fmtinstall('V', vtscorefmt);
+	statsinit();
+
+	ARGBEGIN{
+	case 'v':
+		verbose++;
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	readonly = 1;
+
+	if(argc != 2)
+		usage();
+
+	file = argv[0];
+	aname = argv[1];
+
+	part = initpart(file, 0);
+	if(part == nil)
+		sysfatal("can't open partition %s: %r", file);
+
+	ap = initarenapart(part);
+	if(ap == nil)
+		sysfatal("can't initialize arena partition in %s: %r", file);
+
+	if(verbose)
+		printarenapart(2, ap);
+
+	initdcache(8 * MaxDiskBlock);
+
+	for(i = 0; i < ap->narenas; i++){
+		if(strcmp(ap->arenas[i]->name, aname) == 0){
+			rdarena(ap->arenas[i]);
+			threadexitsall(0);
+		}
+	}
+
+	sysfatal("couldn't find arena %s\n", aname);
+}
diff --git a/src/cmd/venti/read.c b/src/cmd/venti/read.c
new file mode 100644
index 00000000..969a0593
--- /dev/null
+++ b/src/cmd/venti/read.c
@@ -0,0 +1,102 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+char *host;
+
+void
+usage(void)
+{
+	fprint(2, "usage: read [-h host] score [type]\n");
+	threadexitsall("usage");
+}
+
+int
+parsescore(uchar *score, char *buf, int n)
+{
+	int i, c;
+
+	memset(score, 0, VtScoreSize);
+
+	if(n != VtScoreSize*2){
+		werrstr("score wrong length %d", n);
+		return -1;
+	}
+	for(i=0; i<VtScoreSize*2; i++) {
+		if(buf[i] >= '0' && buf[i] <= '9')
+			c = buf[i] - '0';
+		else if(buf[i] >= 'a' && buf[i] <= 'f')
+			c = buf[i] - 'a' + 10;
+		else if(buf[i] >= 'A' && buf[i] <= 'F')
+			c = buf[i] - 'A' + 10;
+		else {
+			c = buf[i];
+			werrstr("bad score char %d '%c'", c, c);
+			return -1;
+		}
+
+		if((i & 1) == 0)
+			c <<= 4;
+	
+		score[i>>1] |= c;
+	}
+	return 0;
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	int type, n;
+	uchar score[VtScoreSize];
+	uchar *buf;
+	VtConn *z;
+
+	ARGBEGIN{
+	case 'h':
+		host = EARGF(usage());
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	if(argc != 1 && argc != 2)
+		usage();
+
+
+	fmtinstall('V', vtscorefmt);
+
+	if(parsescore(score, argv[0], strlen(argv[0])) < 0)
+		sysfatal("could not parse score '%s': %r", argv[0]);
+
+	buf = vtmallocz(VtMaxLumpSize);
+
+	z = vtdial(host);
+	if(z == nil)
+		sysfatal("could not connect to server: %r");
+
+	if(vtconnect(z) < 0)
+		sysfatal("vtconnect: %r");
+
+	if(argc == 1){
+		n = -1;
+		for(type=0; type<VtMaxType; type++){
+			n = vtread(z, score, type, buf, VtMaxLumpSize);
+			if(n >= 0){
+				fprint(2, "venti/read%s%s %V %d\n", host ? " -h" : "", host ? host : "",
+					score, type);
+				break;
+			}
+		}
+	}else{
+		type = atoi(argv[1]);
+		n = vtread(z, score, type, buf, VtMaxLumpSize);
+	}
+	vthangup(z);
+	if(n < 0)
+		sysfatal("could not read block: %r");
+	if(write(1, buf, n) != n)
+		sysfatal("write: %r");
+
+	threadexitsall(0);
+}
diff --git a/src/cmd/venti/score.c b/src/cmd/venti/score.c
new file mode 100644
index 00000000..0809e84f
--- /dev/null
+++ b/src/cmd/venti/score.c
@@ -0,0 +1,43 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+u8int zeroscore[VtScoreSize];
+
+void
+scoremem(u8int *score, u8int *buf, int n)
+{
+	DigestState s;
+
+	memset(&s, 0, sizeof s);
+	sha1(buf, n, score, &s);
+}
+
+static int
+hexv(int c)
+{
+	if(c >= '0' && c <= '9')
+		return c - '0';
+	if(c >= 'a' && c <= 'f')
+		return c - 'a' + 10;
+	if(c >= 'A' && c <= 'F')
+		return c - 'A' + 10;
+	return -1;
+}
+
+int
+strscore(char *s, u8int *score)
+{
+	int i, c, d;
+
+	for(i = 0; i < VtScoreSize; i++){
+		c = hexv(s[2 * i]);
+		if(c < 0)
+			return -1;
+		d = hexv(s[2 * i + 1]);
+		if(d < 0)
+			return -1;
+		score[i] = (c << 4) + d;
+	}
+	return s[2 * i] == '\0';
+}
diff --git a/src/cmd/venti/sortientry.c b/src/cmd/venti/sortientry.c
new file mode 100644
index 00000000..0e9f4b1e
--- /dev/null
+++ b/src/cmd/venti/sortientry.c
@@ -0,0 +1,332 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+typedef struct IEBuck	IEBuck;
+typedef struct IEBucks	IEBucks;
+
+enum
+{
+	ClumpChunks	= 32*1024
+};
+
+struct IEBuck
+{
+	u32int	head;		/* head of chain of chunks on the disk */
+	u32int	used;		/* usage of the last chunk */
+	u64int	total;		/* total number of bytes in this bucket */
+	u8int	*buf;		/* chunk of entries for this bucket */
+};
+
+struct IEBucks
+{
+	Part	*part;
+	u64int	off;		/* offset for writing data in the partition */
+	u32int	chunks;		/* total chunks written to fd */
+	u64int	max;		/* max bytes entered in any one bucket */
+	int	bits;		/* number of bits in initial bucket sort */
+	int	nbucks;		/* 1 << bits, the number of buckets */
+	u32int	size;		/* bytes in each of the buckets chunks */
+	u32int	usable;		/* amount usable for IEntry data */
+	u8int	*buf;		/* buffer for all chunks */
+	IEBuck	*bucks;
+};
+
+#define	U32GET(p)	(((p)[0]<<24)|((p)[1]<<16)|((p)[2]<<8)|(p)[3])
+#define	U32PUT(p,v)	(p)[0]=(v)>>24;(p)[1]=(v)>>16;(p)[2]=(v)>>8;(p)[3]=(v)
+
+static IEBucks	*initiebucks(Part *part, int bits, u32int size);
+static int	flushiebuck(IEBucks *ib, int b, int reset);
+static int	flushiebucks(IEBucks *ib);
+static u32int	sortiebuck(IEBucks *ib, int b);
+static u64int	sortiebucks(IEBucks *ib);
+static int	sprayientry(IEBucks *ib, IEntry *ie);
+static u32int	readarenainfo(IEBucks *ib, Arena *arena, u64int a);
+static u32int	readiebuck(IEBucks *ib, int b);
+static void	freeiebucks(IEBucks *ib);
+
+/*
+ * build a sorted file with all Ientries which should be in ix.
+ * assumes the arenas' directories are up to date.
+ * reads each, converts the entries to index entries,
+ * and sorts them.
+ */
+u64int
+sortrawientries(Index *ix, Part *tmp, u64int *base)
+{
+	IEBucks *ib;
+	u64int clumps, sorted;
+	u32int n;
+	int i, ok;
+
+//ZZZ should allow configuration of bits, bucket size
+	ib = initiebucks(tmp, 8, 64*1024);
+	if(ib == nil){
+		seterr(EOk, "can't create sorting buckets: %r");
+		return TWID64;
+	}
+	ok = 0;
+	clumps = 0;
+	for(i = 0; i < ix->narenas; i++){
+		n = readarenainfo(ib, ix->arenas[i], ix->amap[i].start);
+		if(n == TWID32){
+			ok = -1;
+			break;
+		}
+		clumps += n;
+	}
+fprint(2, "got %lld clumps - starting sort\n", clumps);
+	if(ok){
+		sorted = sortiebucks(ib);
+		*base = (u64int)ib->chunks * ib->size;
+		if(sorted != clumps){
+			fprint(2, "sorting messed up: clumps=%lld sorted=%lld\n", clumps, sorted);
+			ok = -1;
+		}
+	}
+	freeiebucks(ib);
+	if(ok < 0)
+		return TWID64;
+	return clumps;
+}
+
+/*
+ * read in all of the arena's clump directory,
+ * convert to IEntry format, and bucket sort based
+ * on the first few bits.
+ */
+static u32int
+readarenainfo(IEBucks *ib, Arena *arena, u64int a)
+{
+	IEntry ie;
+	ClumpInfo *ci, *cis;
+	u32int clump;
+	int i, n, ok;
+
+//ZZZ remove fprint?
+	if(arena->clumps)
+		fprint(2, "reading directory for arena=%s with %d entries\n", arena->name, arena->clumps);
+
+	cis = MKN(ClumpInfo, ClumpChunks);
+	ok = 0;
+	memset(&ie, 0, sizeof(IEntry));
+	for(clump = 0; clump < arena->clumps; clump += n){
+		n = ClumpChunks;
+		if(n > arena->clumps - clump)
+			n = arena->clumps - clump;
+		if(readclumpinfos(arena, clump, cis, n) != n){
+			seterr(EOk, "arena directory read failed: %r");
+			ok = -1;
+			break;
+		}
+
+		for(i = 0; i < n; i++){
+			ci = &cis[i];
+			ie.ia.type = ci->type;
+			ie.ia.size = ci->uncsize;
+			ie.ia.addr = a;
+			a += ci->size + ClumpSize;
+			ie.ia.blocks = (ci->size + ClumpSize + (1 << ABlockLog) - 1) >> ABlockLog;
+			scorecp(ie.score, ci->score);
+			sprayientry(ib, &ie);
+		}
+	}
+	free(cis);
+	if(ok < 0)
+		return TWID32;
+	return clump;
+}
+
+/*
+ * initialize the external bucket sorting data structures
+ */
+static IEBucks*
+initiebucks(Part *part, int bits, u32int size)
+{
+	IEBucks *ib;
+	int i;
+
+	ib = MKZ(IEBucks);
+	if(ib == nil){
+		seterr(EOk, "out of memory");
+		return nil;
+	}
+	ib->bits = bits;
+	ib->nbucks = 1 << bits;
+	ib->size = size;
+	ib->usable = (size - U32Size) / IEntrySize * IEntrySize;
+	ib->bucks = MKNZ(IEBuck, ib->nbucks);
+	if(ib->bucks == nil){
+		seterr(EOk, "out of memory allocation sorting buckets");
+		freeiebucks(ib);
+		return nil;
+	}
+	ib->buf = MKN(u8int, size * (1 << bits));
+	if(ib->buf == nil){
+		seterr(EOk, "out of memory allocating sorting buckets' buffers");
+		freeiebucks(ib);
+		return nil;
+	}
+	for(i = 0; i < ib->nbucks; i++){
+		ib->bucks[i].head = TWID32;
+		ib->bucks[i].buf = &ib->buf[i * size];
+	}
+	ib->part = part;
+	return ib;
+}
+
+static void
+freeiebucks(IEBucks *ib)
+{
+	if(ib == nil)
+		return;
+	free(ib->bucks);
+	free(ib->buf);
+	free(ib);
+}
+
+/*
+ * initial sort: put the entry into the correct bucket
+ */
+static int
+sprayientry(IEBucks *ib, IEntry *ie)
+{
+	u32int n;
+	int b;
+
+	b = hashbits(ie->score, ib->bits);
+	n = ib->bucks[b].used;
+	packientry(ie, &ib->bucks[b].buf[n]);
+	n += IEntrySize;
+	ib->bucks[b].used = n;
+	if(n + IEntrySize <= ib->usable)
+		return 0;
+	return flushiebuck(ib, b, 1);
+}
+
+/*
+ * finish sorting:
+ * for each bucket, read it in and sort it
+ * write out the the final file
+ */
+static u64int
+sortiebucks(IEBucks *ib)
+{
+	u64int tot;
+	u32int n;
+	int i;
+
+	if(flushiebucks(ib) < 0)
+		return TWID64;
+	for(i = 0; i < ib->nbucks; i++)
+		ib->bucks[i].buf = nil;
+	ib->off = (u64int)ib->chunks * ib->size;
+	free(ib->buf);
+fprint(2, "ib->max = %lld\n", ib->max);
+fprint(2, "ib->chunks = %ud\n", ib->chunks);
+	ib->buf = MKN(u8int, ib->max + U32Size);
+	if(ib->buf == nil){
+		seterr(EOk, "out of memory allocating final sorting buffer; try more buckets");
+		return TWID64;
+	}
+	tot = 0;
+	for(i = 0; i < ib->nbucks; i++){
+		n = sortiebuck(ib, i);
+		if(n == TWID32)
+			return TWID64;
+		tot += n;
+	}
+	return tot;
+	return 0;
+}
+
+/*
+ * sort from bucket b of ib into the output file to
+ */
+static u32int
+sortiebuck(IEBucks *ib, int b)
+{
+	u32int n;
+
+	n = readiebuck(ib, b);
+	if(n == TWID32)
+		return TWID32;
+	qsort(ib->buf, n, IEntrySize, ientrycmp);
+	if(writepart(ib->part, ib->off, ib->buf, n * IEntrySize) < 0){
+		seterr(EOk, "can't write sorted bucket: %r");
+		return TWID32;
+	}
+	ib->off += n * IEntrySize;
+	return n;
+}
+
+/*
+ * write out a single bucket
+ */
+static int
+flushiebuck(IEBucks *ib, int b, int reset)
+{
+	u32int n;
+
+	if(ib->bucks[b].used == 0)
+		return 0;
+	n = ib->bucks[b].used;
+	U32PUT(&ib->bucks[b].buf[n], ib->bucks[b].head);
+	n += U32Size;
+	if(writepart(ib->part, (u64int)ib->chunks * ib->size, ib->bucks[b].buf, n) < 0){
+		seterr(EOk, "can't write sorting bucket to file: %r");
+		return -1;
+	}
+	ib->bucks[b].head = ib->chunks++;
+	ib->bucks[b].total += ib->bucks[b].used;
+	if(reset)
+		ib->bucks[b].used = 0;
+	return 0;
+}
+
+/*
+ * write out all of the buckets, and compute
+ * the maximum size of any bucket
+ */
+static int
+flushiebucks(IEBucks *ib)
+{
+	int i;
+
+	for(i = 0; i < ib->nbucks; i++){
+		if(flushiebuck(ib, i, 0) < 0)
+			return -1;
+		if(ib->bucks[i].total > ib->max)
+			ib->max = ib->bucks[i].total;
+	}
+	return 0;
+}
+
+/*
+ * read in the chained buffers for bucket b,
+ * and return it's total number of IEntries
+ */
+static u32int
+readiebuck(IEBucks *ib, int b)
+{
+	u32int head, n, m;
+
+	head = ib->bucks[b].head;
+	n = 0;
+	m = ib->bucks[b].used;
+	if(m == 0)
+		m = ib->usable;
+fprint(2, "%d total = %lld\n", b, ib->bucks[b].total);
+	while(head != TWID32){
+		if(readpart(ib->part, (u64int)head * ib->size, &ib->buf[n], m + U32Size) < 0){
+fprint(2, "n = %ud\n", n);
+			seterr(EOk, "can't read index sort bucket: %r");
+			return TWID32;
+		}
+		n += m;
+		head = U32GET(&ib->buf[n]);
+		m = ib->usable;
+	}
+fprint(2, "n = %ud\n", n);
+	return n / IEntrySize;
+}
diff --git a/src/cmd/venti/stats.c b/src/cmd/venti/stats.c
new file mode 100644
index 00000000..edf79bd7
--- /dev/null
+++ b/src/cmd/venti/stats.c
@@ -0,0 +1,64 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+Stats stats;
+
+void
+statsinit(void)
+{
+}
+
+static int
+percent(long v, long total)
+{
+	if(total == 0)
+		total = 1;
+	if(v < 1000*1000)
+		return (v * 100) / total;
+	total /= 100;
+	if(total == 0)
+		total = 1;
+	return v / total;
+}
+
+void
+printstats(void)
+{
+	fprint(2, "lump writes=%,ld\n", stats.lumpwrites);
+	fprint(2, "lump reads=%,ld\n", stats.lumpreads);
+	fprint(2, "lump cache read hits=%,ld\n", stats.lumphit);
+	fprint(2, "lump cache read misses=%,ld\n", stats.lumpmiss);
+
+	fprint(2, "clump disk writes=%,ld\n", stats.clumpwrites);
+	fprint(2, "clump disk bytes written=%,lld\n", stats.clumpbwrites);
+	fprint(2, "clump disk bytes compressed=%,lld\n", stats.clumpbcomp);
+	fprint(2, "clump disk reads=%,ld\n", stats.clumpreads);
+	fprint(2, "clump disk bytes read=%,lld\n", stats.clumpbreads);
+	fprint(2, "clump disk bytes uncompressed=%,lld\n", stats.clumpbuncomp);
+
+	fprint(2, "clump directory disk writes=%,ld\n", stats.ciwrites);
+	fprint(2, "clump directory disk reads=%,ld\n", stats.cireads);
+
+	fprint(2, "index disk writes=%,ld\n", stats.indexwrites);
+	fprint(2, "index disk reads=%,ld\n", stats.indexreads);
+	fprint(2, "index disk reads for modify=%,ld\n", stats.indexwreads);
+	fprint(2, "index disk reads for allocation=%,ld\n", stats.indexareads);
+
+	fprint(2, "index cache lookups=%,ld\n", stats.iclookups);
+	fprint(2, "index cache hits=%,ld %d%%\n", stats.ichits,
+		percent(stats.ichits, stats.iclookups));
+	fprint(2, "index cache fills=%,ld %d%%\n", stats.icfills,
+		percent(stats.icfills, stats.iclookups));
+	fprint(2, "index cache inserts=%,ld\n", stats.icinserts);
+
+	fprint(2, "disk cache hits=%,ld\n", stats.pchit);
+	fprint(2, "disk cache misses=%,ld\n", stats.pcmiss);
+	fprint(2, "disk cache reads=%,ld\n", stats.pcreads);
+	fprint(2, "disk cache bytes read=%,lld\n", stats.pcbreads);
+
+	fprint(2, "disk writes=%,ld\n", stats.diskwrites);
+	fprint(2, "disk bytes written=%,lld\n", stats.diskbwrites);
+	fprint(2, "disk reads=%,ld\n", stats.diskreads);
+	fprint(2, "disk bytes read=%,lld\n", stats.diskbreads);
+}
diff --git a/src/cmd/venti/stdinc.h b/src/cmd/venti/stdinc.h
new file mode 100644
index 00000000..6f8f5ba5
--- /dev/null
+++ b/src/cmd/venti/stdinc.h
@@ -0,0 +1,6 @@
+#include <u.h>
+#include <libc.h>
+#include <venti.h>
+#include <libsec.h>
+#include <thread.h>
+
diff --git a/src/cmd/venti/sync.c b/src/cmd/venti/sync.c
new file mode 100644
index 00000000..74461400
--- /dev/null
+++ b/src/cmd/venti/sync.c
@@ -0,0 +1,48 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+char *host;
+
+void
+usage(void)
+{
+	fprint(2, "usage: sync [-h host]\n");
+	threadexitsall("usage");
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	VtConn *z;
+
+	ARGBEGIN{
+	case 'h':
+		host = EARGF(usage());
+		if(host == nil)
+			usage();
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	if(argc != 0)
+		usage();
+
+
+	fmtinstall('V', vtscorefmt);
+
+	z = vtdial(host);
+	if(z == nil)
+		sysfatal("could not connect to server: %r");
+
+	if(vtconnect(z) < 0)
+		sysfatal("vtconnect: %r");
+
+	if(vtsync(z) < 0)
+		sysfatal("vtsync: %r");
+
+	vthangup(z);
+	threadexitsall(0);
+}
diff --git a/src/cmd/venti/syncarena.c b/src/cmd/venti/syncarena.c
new file mode 100644
index 00000000..78a6bd0f
--- /dev/null
+++ b/src/cmd/venti/syncarena.c
@@ -0,0 +1,164 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+static int	writeclumphead(Arena *arena, u64int aa, Clump *cl);
+static int	writeclumpmagic(Arena *arena, u64int aa, u32int magic);
+
+int
+clumpinfocmp(ClumpInfo *c, ClumpInfo *d)
+{
+	return c->type != d->type
+		|| c->size != d->size
+		|| c->uncsize != d->uncsize
+		|| scorecmp(c->score, d->score)!=0;
+}
+
+/*
+ * synchronize the clump info directory with
+ * with the clumps actually stored in the arena.
+ * the directory should be at least as up to date
+ * as the arena's trailer.
+ *
+ * checks/updates at most n clumps.
+ *
+ * returns 0 if ok, flags if error occurred
+ */
+int
+syncarena(Arena *arena, u32int n, int zok, int fix)
+{
+	ZBlock *lump;
+	Clump cl;
+	ClumpInfo ci;
+	static ClumpInfo zci = { .type = -1 };
+	u8int score[VtScoreSize];
+	u64int uncsize, used, aa;
+	u32int clump, clumps, cclumps, magic;
+	int err, flush, broken;
+
+	used = arena->used;
+	clumps = arena->clumps;
+	cclumps = arena->cclumps;
+	uncsize = arena->uncsize;
+
+	flush = 0;
+	err = 0;
+	for(; n; n--){
+		aa = arena->used;
+		clump = arena->clumps;
+		magic = clumpmagic(arena, aa);
+		if(magic == ClumpFreeMagic)
+			break;
+		if(magic != ClumpMagic){
+			fprint(2, "illegal clump magic number=%#8.8ux at clump=%d\n", magic, clump);
+			err |= SyncDataErr;
+//ZZZ write a zero here?
+			if(0 && fix && writeclumpmagic(arena, aa, ClumpFreeMagic) < 0){
+				fprint(2, "can't write corrected clump free magic: %r");
+				err |= SyncFixErr;
+			}
+			break;
+		}
+		arena->clumps++;
+
+		broken = 0;
+		lump = loadclump(arena, aa, 0, &cl, score, 0);
+		if(lump == nil){
+			fprint(2, "clump=%d failed to read correctly: %r\n", clump);
+			err |= SyncDataErr;
+		}else if(cl.info.type != VtTypeCorrupt){
+			scoremem(score, lump->data, cl.info.uncsize);
+			if(scorecmp(cl.info.score, score) != 0){
+				fprint(2, "clump=%d has mismatched score\n", clump);
+				err |= SyncDataErr;
+				broken = 1;
+			}else if(vttypevalid(cl.info.type) < 0){
+				fprint(2, "clump=%d has invalid type %d", clump, cl.info.type);
+				err |= SyncDataErr;
+				broken = 1;
+			}
+			if(broken && fix){
+				cl.info.type = VtTypeCorrupt;
+				if(writeclumphead(arena, aa, &cl) < 0){
+					fprint(2, "can't write corrected clump header: %r");
+					err |= SyncFixErr;
+				}
+			}
+		}
+		freezblock(lump);
+		arena->used += ClumpSize + cl.info.size;
+
+		if(!broken && readclumpinfo(arena, clump, &ci)<0){
+			fprint(2, "arena directory read failed\n");
+			broken = 1;
+		}else if(!broken && clumpinfocmp(&ci, &cl.info)!=0){
+			if(clumpinfocmp(&ci, &zci) == 0){
+				err |= SyncCIZero;
+				if(!zok)
+					fprint(2, "unwritten clump info for clump=%d\n", clump);
+			}else{
+				err |= SyncCIErr;
+				fprint(2, "bad clump info for clump=%d\n", clump);
+				fprint(2, "\texpected score=%V type=%d size=%d uncsize=%d\n",
+					cl.info.score, cl.info.type, cl.info.size, cl.info.uncsize);
+				fprint(2, "\tfound score=%V type=%d size=%d uncsize=%d\n",
+					ci.score, ci.type, ci.size, ci.uncsize);
+			}
+			broken = 1;
+		}
+		if(broken && fix){
+			flush = 1;
+			ci = cl.info;
+			if(writeclumpinfo(arena, clump, &ci) < 0){
+				fprint(2, "can't write correct clump directory: %r\n");
+				err |= SyncFixErr;
+			}
+		}
+
+		arena->uncsize += cl.info.uncsize;
+		if(cl.info.size < cl.info.uncsize)
+			arena->cclumps++;
+	}
+
+	if(flush){
+		arena->wtime = now();
+		if(arena->ctime == 0 && arena->clumps)
+			arena->ctime = arena->wtime;
+		if(flushciblocks(arena) < 0){
+			fprint(2, "can't flush arena directory cache: %r");
+			err |= SyncFixErr;
+		}
+	}
+
+	if(used != arena->used
+	|| clumps != arena->clumps
+	|| cclumps != arena->cclumps
+	|| uncsize != arena->uncsize)
+		err |= SyncHeader;
+
+	return err;
+}
+
+static int
+writeclumphead(Arena *arena, u64int aa, Clump *cl)
+{
+	ZBlock *zb;
+	int bad;
+
+	zb = alloczblock(ClumpSize, 0);
+	if(zb == nil)
+		return -1;
+	bad = packclump(cl, zb->data)<0
+		|| writearena(arena, aa, zb->data, ClumpSize) != ClumpSize;
+	freezblock(zb);
+	return bad ? -1 : 0;
+}
+
+static int
+writeclumpmagic(Arena *arena, u64int aa, u32int magic)
+{
+	u8int buf[U32Size];
+
+	packmagic(magic, buf);
+	return writearena(arena, aa, buf, U32Size) == U32Size;
+}
diff --git a/src/cmd/venti/syncindex.c b/src/cmd/venti/syncindex.c
new file mode 100644
index 00000000..75bb0696
--- /dev/null
+++ b/src/cmd/venti/syncindex.c
@@ -0,0 +1,56 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+static	int	verbose;
+void
+usage(void)
+{
+	fprint(2, "usage: syncindex [-fv] [-B blockcachesize] config\n");
+	threadexitsall("usage");
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	u32int bcmem;
+	int fix;
+
+	fix = 0;
+	bcmem = 0;
+	ARGBEGIN{
+	case 'B':
+		bcmem = unittoull(ARGF());
+		break;
+	case 'f':
+		fix++;
+		break;
+	case 'v':
+		verbose++;
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	if(!fix)
+		readonly = 1;
+
+	if(argc != 1)
+		usage();
+
+	if(initventi(argv[0]) < 0)
+		sysfatal("can't init venti: %r");
+
+	if(bcmem < maxblocksize * (mainindex->narenas + mainindex->nsects * 4 + 16))
+		bcmem = maxblocksize * (mainindex->narenas + mainindex->nsects * 4 + 16);
+	fprint(2, "initialize %d bytes of disk block cache\n", bcmem);
+	initdcache(bcmem);
+
+	if(verbose)
+		printindex(2, mainindex);
+	if(syncindex(mainindex, fix) < 0)
+		sysfatal("failed to sync index=%s: %r\n", mainindex->name);
+
+	threadexitsall(0);
+}
diff --git a/src/cmd/venti/syncindex0.c b/src/cmd/venti/syncindex0.c
new file mode 100644
index 00000000..95db1208
--- /dev/null
+++ b/src/cmd/venti/syncindex0.c
@@ -0,0 +1,144 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+enum
+{
+	ClumpChunks	= 32*1024
+};
+
+/*
+ * shell sort is plenty good enough
+ * because we're going to do a bunch of disk i/o's
+ */
+static void
+sortclumpinfo(ClumpInfo *ci, int *s, int n)
+{
+	int i, j, m, t;
+
+	for(m = (n + 3) / 5; m > 0; m = (m + 1) / 3){
+		for(i = n - m; i-- > 0;){
+			for(j = i + m; j < n; j += m){
+				if(memcmp(ci[s[j - m]].score, ci[s[j]].score, VtScoreSize) <= 0)
+					break;
+				t = s[j];
+				s[j] = s[j - m];
+				s[j - m] = t;
+			}
+		}
+	}
+}
+
+int
+syncarenaindex(Index *ix, Arena *arena, u32int clump, u64int a, int fix)
+{
+	Packet *pack;
+	IEntry ie;
+	IAddr ia;
+	ClumpInfo *ci, *cis;
+	u32int now;
+	u64int *addrs;
+	int i, n, ok, *s;
+
+	now = time(nil);
+	cis = MKN(ClumpInfo, ClumpChunks);
+	addrs = MKN(u64int, ClumpChunks);
+	s = MKN(int, ClumpChunks);
+	ok = 0;
+	for(; clump < arena->clumps; clump += n){
+		n = ClumpChunks;
+		if(n > arena->clumps - clump)
+			n = arena->clumps - clump;
+		n = readclumpinfos(arena, clump, cis, n);
+		if(n <= 0){
+			fprint(2, "arena directory read failed\n");
+			ok = -1;
+			break;
+		}
+
+		for(i = 0; i < n; i++){
+			addrs[i] = a;
+			a += cis[i].size + ClumpSize;
+			s[i] = i;
+		}
+
+		sortclumpinfo(cis, s, n);
+
+		for(i = 0; i < n; i++){
+			ci = &cis[s[i]];
+			ia.type = ci->type;
+			ia.size = ci->uncsize;
+			ia.addr = addrs[s[i]];
+			ia.blocks = (ci->size + ClumpSize + (1 << ABlockLog) - 1) >> ABlockLog;
+
+			if(loadientry(ix, ci->score, ci->type, &ie) < 0)
+				fprint(2, "missing block type=%d score=%V\n", ci->type, ci->score);
+			else if(iaddrcmp(&ia, &ie.ia) != 0){
+				fprint(2, "\nmismatched index entry and clump at %d\n", clump + i);
+				fprint(2, "\tclump: type=%d size=%d blocks=%d addr=%lld\n", ia.type, ia.size, ia.blocks, ia.addr);
+				fprint(2, "\tindex: type=%d size=%d block=%d addr=%lld\n", ie.ia.type, ie.ia.size, ie.ia.blocks, ie.ia.addr);
+				pack = readlump(ie.score, ie.ia.type, ie.ia.size);
+				packetfree(pack);
+				if(pack != nil){
+					fprint(2, "duplicated lump\n");
+					continue;
+				}
+			}else
+				continue;
+			if(!fix){
+				ok = -1;
+				continue;
+			}
+			ie.ia = ia;
+			scorecp(ie.score, ci->score);
+			ie.train = 0;
+			ie.wtime = now;
+			if(storeientry(ix, &ie) < 0){
+				fprint(2, "can't fix index: %r");
+				ok = -1;
+			}
+		}
+
+		if(0 && clump / 1000 != (clump + n) / 1000)
+			fprint(2, ".");
+	}
+	free(cis);
+	free(addrs);
+	free(s);
+	return ok;
+}
+
+int
+syncindex(Index *ix, int fix)
+{
+	Arena *arena;
+	u64int a;
+	u32int clump;
+	int i, e, e1, ok, ok1;
+
+	ok = 0;
+	for(i = 0; i < ix->narenas; i++){
+		arena = ix->arenas[i];
+		clump = arena->clumps;
+		a = arena->used;
+		e = syncarena(arena, TWID32, fix, fix);
+		e1 = e;
+		if(fix)
+			e1 &= ~(SyncHeader|SyncCIZero);
+		if(e1 == SyncHeader)
+			fprint(2, "arena %s: header is out-of-date\n", arena->name);
+		if(e1)
+			ok = -1;
+		else{
+			ok1 = syncarenaindex(ix, arena, clump, a + ix->amap[i].start, fix);
+			if(fix && ok1==0 && (e & SyncHeader) && wbarena(arena) < 0)
+				fprint(2, "arena=%s header write failed: %r\n", arena->name);
+			ok |= ok1;
+		}
+	}
+	if(fix && wbindex(ix) < 0){
+		fprint(2, "can't write back index header for %s: %r\n", ix->name);
+		return -1;
+	}
+	return ok;
+}
diff --git a/src/cmd/venti/unittoull.c b/src/cmd/venti/unittoull.c
new file mode 100644
index 00000000..db35aa0f
--- /dev/null
+++ b/src/cmd/venti/unittoull.c
@@ -0,0 +1,27 @@
+#include "stdinc.h"
+
+#define TWID64	((u64int)~(u64int)0)
+
+u64int
+unittoull(char *s)
+{
+	char *es;
+	u64int n;
+
+	if(s == nil)
+		return TWID64;
+	n = strtoul(s, &es, 0);
+	if(*es == 'k' || *es == 'K'){
+		n *= 1024;
+		es++;
+	}else if(*es == 'm' || *es == 'M'){
+		n *= 1024*1024;
+		es++;
+	}else if(*es == 'g' || *es == 'G'){
+		n *= 1024*1024*1024;
+		es++;
+	}
+	if(*es != '\0')
+		return TWID64;
+	return n;
+}
diff --git a/src/cmd/venti/unwhack.c b/src/cmd/venti/unwhack.c
new file mode 100644
index 00000000..5530bd07
--- /dev/null
+++ b/src/cmd/venti/unwhack.c
@@ -0,0 +1,179 @@
+#include "stdinc.h"
+#include "whack.h"
+
+enum
+{
+	DMaxFastLen	= 7,
+	DBigLenCode	= 0x3c,		/* minimum code for large lenth encoding */
+	DBigLenBits	= 6,
+	DBigLenBase	= 1		/* starting items to encode for big lens */
+};
+
+static uchar lenval[1 << (DBigLenBits - 1)] =
+{
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+	3, 3, 3, 3, 3, 3, 3, 3,
+	4, 4, 4, 4,
+	5,
+	6,
+	255,
+	255
+};
+
+static uchar lenbits[] =
+{
+	0, 0, 0,
+	2, 3, 5, 5,
+};
+
+static uchar offbits[16] =
+{
+	5, 5, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 12, 13
+};
+
+static ushort offbase[16] =
+{
+	0, 0x20,
+	0x40, 0x60,
+	0x80, 0xc0,
+	0x100, 0x180,
+	0x200, 0x300,
+	0x400, 0x600,
+	0x800, 0xc00,
+	0x1000,
+	0x2000
+};
+
+void
+unwhackinit(Unwhack *uw)
+{
+	uw->err[0] = '\0';
+}
+
+int
+unwhack(Unwhack *uw, uchar *dst, int ndst, uchar *src, int nsrc)
+{
+	uchar *s, *d, *dmax, *smax, lit;
+	ulong uwbits, lithist;
+	int i, off, len, bits, use, code, uwnbits, overbits;
+
+	d = dst;
+	dmax = d + ndst;
+
+	smax = src + nsrc;
+	uwnbits = 0;
+	uwbits = 0;
+	overbits = 0;
+	lithist = ~0;
+	while(src < smax || uwnbits - overbits >= MinDecode){
+		while(uwnbits <= 24){
+			uwbits <<= 8;
+			if(src < smax)
+				uwbits |= *src++;
+			else
+				overbits += 8;
+			uwnbits += 8;
+		}
+
+		/*
+		 * literal
+		 */
+		len = lenval[(uwbits >> (uwnbits - 5)) & 0x1f];
+		if(len == 0){
+			if(lithist & 0xf){
+				uwnbits -= 9;
+				lit = (uwbits >> uwnbits) & 0xff;
+				lit &= 255;
+			}else{
+				uwnbits -= 8;
+				lit = (uwbits >> uwnbits) & 0x7f;
+				if(lit < 32){
+					if(lit < 24){
+						uwnbits -= 2;
+						lit = (lit << 2) | ((uwbits >> uwnbits) & 3);
+					}else{
+						uwnbits -= 3;
+						lit = (lit << 3) | ((uwbits >> uwnbits) & 7);
+					}
+					lit = (lit - 64) & 0xff;
+				}
+			}
+			if(d >= dmax){
+				snprint(uw->err, WhackErrLen, "too much output");
+				return -1;
+			}
+			*d++ = lit;
+			lithist = (lithist << 1) | (lit < 32) | (lit > 127);
+			continue;
+		}
+
+		/*
+		 * length
+		 */
+		if(len < 255)
+			uwnbits -= lenbits[len];
+		else{
+			uwnbits -= DBigLenBits;
+			code = ((uwbits >> uwnbits) & ((1 << DBigLenBits) - 1)) - DBigLenCode;
+			len = DMaxFastLen;
+			use = DBigLenBase;
+			bits = (DBigLenBits & 1) ^ 1;
+			while(code >= use){
+				len += use;
+				code -= use;
+				code <<= 1;
+				uwnbits--;
+				if(uwnbits < 0){
+					snprint(uw->err, WhackErrLen, "len out of range");
+					return -1;
+				}
+				code |= (uwbits >> uwnbits) & 1;
+				use <<= bits;
+				bits ^= 1;
+			}
+			len += code;
+
+			while(uwnbits <= 24){
+				uwbits <<= 8;
+				if(src < smax)
+					uwbits |= *src++;
+				else
+					overbits += 8;
+				uwnbits += 8;
+			}
+		}
+
+		/*
+		 * offset
+		 */
+		uwnbits -= 4;
+		bits = (uwbits >> uwnbits) & 0xf;
+		off = offbase[bits];
+		bits = offbits[bits];
+
+		uwnbits -= bits;
+		off |= (uwbits >> uwnbits) & ((1 << bits) - 1);
+		off++;
+
+		if(off > d - dst){
+			snprint(uw->err, WhackErrLen, "offset out of range: off=%d d=%ld len=%d nbits=%d", off, d - dst, len, uwnbits);
+			return -1;
+		}
+		if(d + len > dmax){
+			snprint(uw->err, WhackErrLen, "len out of range");
+			return -1;
+		}
+		s = d - off;
+		for(i = 0; i < len; i++)
+			d[i] = s[i];
+		d += len;
+	}
+	if(uwnbits < overbits){
+		snprint(uw->err, WhackErrLen, "compressed data overrun");
+		return -1;
+	}
+
+	len = d - dst;
+
+	return len;
+}
diff --git a/src/cmd/venti/utils.c b/src/cmd/venti/utils.c
new file mode 100644
index 00000000..26a0ef82
--- /dev/null
+++ b/src/cmd/venti/utils.c
@@ -0,0 +1,361 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+int
+namecmp(char *s, char *t)
+{
+	return strncmp(s, t, ANameSize);
+}
+
+void
+namecp(char *dst, char *src)
+{
+	strncpy(dst, src, ANameSize - 1);
+	dst[ANameSize - 1] = '\0';
+}
+
+int
+nameok(char *name)
+{
+	char *t;
+	int c;
+
+	if(name == nil)
+		return -1;
+	for(t = name; c = *t; t++)
+		if(t - name >= ANameSize
+		|| c < ' ' || c >= 0x7f)
+			return -1;
+	return 0;
+}
+
+int
+stru32int(char *s, u32int *r)
+{
+	char *t;
+	u32int n, nn, m;
+	int c;
+
+	m = TWID32 / 10;
+	n = 0;
+	for(t = s; ; t++){
+		c = *t;
+		if(c < '0' || c > '9')
+			break;
+		if(n > m)
+			return -1;
+		nn = n * 10 + c - '0';
+		if(nn < n)
+			return -1;
+		n = nn;
+	}
+	*r = n;
+	return s != t && *t == '\0';
+}
+
+int
+stru64int(char *s, u64int *r)
+{
+	char *t;
+	u64int n, nn, m;
+	int c;
+
+	m = TWID64 / 10;
+	n = 0;
+	for(t = s; ; t++){
+		c = *t;
+		if(c < '0' || c > '9')
+			break;
+		if(n > m)
+			return -1;
+		nn = n * 10 + c - '0';
+		if(nn < n)
+			return -1;
+		n = nn;
+	}
+	*r = n;
+	return s != t && *t == '\0';
+}
+
+int
+vttypevalid(int type)
+{
+	return type < VtMaxType;
+}
+
+void
+fmtzbinit(Fmt *f, ZBlock *b)
+{
+	f->runes = 0;
+	f->start = b->data;
+	f->to = f->start;
+	f->stop = (char*)f->start + b->len;
+	f->flush = nil;
+	f->farg = nil;
+	f->nfmt = 0;
+	f->args = nil;
+}
+
+static int
+sflush(Fmt *f)
+{
+	char *s;
+	int n;
+
+	n = (int)f->farg;
+	n += 256;
+	f->farg = (void*)n;
+	s = f->start;
+	f->start = realloc(s, n);
+	if(f->start == nil){
+		f->start = s;
+		return 0;
+	}
+	f->to = (char*)f->start + ((char*)f->to - s);
+	f->stop = (char*)f->start + n - 1;
+	return 1;
+}
+
+static char*
+logit(int severity, char *fmt, va_list args)
+{
+	Fmt f;
+	int n;
+
+	f.runes = 0;
+	n = 32;
+	f.start = malloc(n);
+	if(f.start == nil)
+		return nil;
+	f.to = f.start;
+	f.stop = (char*)f.start + n - 1;
+	f.flush = sflush;
+	f.farg = (void*)n;
+	f.nfmt = 0;
+	f.args = args;
+	n = dofmt(&f, fmt);
+	if(n < 0)
+{
+fprint(2, "dofmt %s failed\n", fmt);
+		return nil;
+}
+	*(char*)f.to = '\0';
+
+	if(argv0 == nil)
+		fprint(2, "%s: err %d: %s\n", argv0, severity, f.start);
+	else
+		fprint(2, "err %d: %s\n", severity, f.start);
+	return f.start;
+}
+
+void
+seterr(int severity, char *fmt, ...)
+{
+	char *s;
+	va_list args;
+
+	va_start(args, fmt);
+	s = logit(severity, fmt, args);
+	va_end(args);
+	if(s == nil)
+		werrstr("error setting error");
+	else{
+		werrstr("%s", s);
+		free(s);
+	}
+}
+
+void
+logerr(int severity, char *fmt, ...)
+{
+	char *s;
+	va_list args;
+
+	va_start(args, fmt);
+	s = logit(severity, fmt, args);
+	va_end(args);
+	free(s);
+}
+
+u32int
+now(void)
+{
+	return time(nil);
+}
+
+void
+fatal(char *fmt, ...)
+{
+	Fmt f;
+	char buf[256];
+
+	f.runes = 0;
+	f.start = buf;
+	f.to = buf;
+	f.stop = buf + sizeof(buf);
+	f.flush = fmtfdflush;
+	f.farg = (void*)2;
+	f.nfmt = 0;
+	fmtprint(&f, "fatal %s error:", argv0);
+	va_start(f.args, fmt);
+	dofmt(&f, fmt);
+	va_end(f.args);
+	fmtprint(&f, "\n");
+	fmtfdflush(&f);
+	if(0)
+		abort();
+	threadexitsall(buf);
+}
+
+ZBlock *
+alloczblock(u32int size, int zeroed)
+{
+	ZBlock *b;
+	static ZBlock z;
+
+	b = malloc(sizeof(ZBlock) + size);
+	if(b == nil){
+		seterr(EOk, "out of memory");
+		return nil;
+	}
+
+	*b = z;
+	b->data = (u8int*)&b[1];
+	b->len = size;
+	if(zeroed)
+		memset(b->data, 0, size);
+	return b;
+}
+
+void
+freezblock(ZBlock *b)
+{
+	free(b);
+}
+
+ZBlock*
+packet2zblock(Packet *p, u32int size)
+{
+	ZBlock *b;
+
+	if(p == nil)
+		return nil;
+	b = alloczblock(size, 0);
+	if(b == nil)
+		return nil;
+	b->len = size;
+	if(packetcopy(p, b->data, 0, size) < 0){
+		freezblock(b);
+		return nil;
+	}
+	return b;
+}
+
+Packet*
+zblock2packet(ZBlock *zb, u32int size)
+{
+	Packet *p;
+
+	if(zb == nil)
+		return nil;
+	p = packetalloc();
+	packetappend(p, zb->data, size);
+	return p;
+}
+
+void *
+emalloc(ulong n)
+{
+	void *p;
+
+	p = malloc(n);
+	if(p == nil)
+		sysfatal("out of memory");
+	memset(p, 0xa5, n);
+if(0)print("emalloc %p-%p by %lux\n", p, (char*)p+n, getcallerpc(&n));
+	return p;
+}
+
+void *
+ezmalloc(ulong n)
+{
+	void *p;
+
+	p = malloc(n);
+	if(p == nil)
+		sysfatal("out of memory");
+	memset(p, 0, n);
+if(0)print("ezmalloc %p-%p by %lux\n", p, (char*)p+n, getcallerpc(&n));
+	return p;
+}
+
+void *
+erealloc(void *p, ulong n)
+{
+	p = realloc(p, n);
+	if(p == nil)
+		sysfatal("out of memory");
+if(0)print("erealloc %p-%p by %lux\n", p, (char*)p+n, getcallerpc(&p));
+	return p;
+}
+
+char *
+estrdup(char *s)
+{
+	char *t;
+	int n;
+
+	n = strlen(s) + 1;
+	t = emalloc(n);
+	memmove(t, s, n);
+if(0)print("estrdup %p-%p by %lux\n", t, (char*)t+n, getcallerpc(&s));
+	return t;
+}
+
+ZBlock*
+readfile(char *name)
+{
+	Part *p;
+	ZBlock *b;
+
+	p = initpart(name, 1);
+	if(p == nil)
+		return nil;
+	b = alloczblock(p->size, 0);
+	if(b == nil){
+		seterr(EOk, "can't alloc %s: %r", name);
+		freepart(p);
+		return nil;
+	}
+	if(readpart(p, 0, b->data, p->size) < 0){
+		seterr(EOk, "can't read %s: %r", name);
+		freepart(p);
+		freezblock(b);
+		return nil;
+	}
+	freepart(p);
+	return b;
+}
+
+/*
+ * return floor(log2(v))
+ */
+int
+u64log2(u64int v)
+{
+	int i;
+
+	for(i = 0; i < 64; i++)
+		if((v >> i) <= 1)
+			break;
+	return i;
+}
+
+int
+vtproc(void (*fn)(void*), void *arg)
+{
+	proccreate(fn, arg, 256*1024);
+	return 0;
+}
+
diff --git a/src/cmd/venti/venti.c b/src/cmd/venti/venti.c
new file mode 100644
index 00000000..6423f7fa
--- /dev/null
+++ b/src/cmd/venti/venti.c
@@ -0,0 +1,172 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+#include "whack.h"
+
+int debug;
+int mainstacksize = 256*1024;
+
+static void	ventiserver(char *vaddr);
+
+void
+threadmain(int argc, char *argv[])
+{
+	char *config, *haddr, *vaddr;
+	u32int mem, icmem, bcmem, minbcmem;
+
+	vaddr = "tcp!*!venti";
+	haddr = nil;
+	config = nil;
+	mem = 0xffffffffUL;
+	icmem = 0;
+	bcmem = 0;
+	ARGBEGIN{
+	case 'a':
+		vaddr = ARGF();
+		if(vaddr == nil)
+			goto usage;
+		break;
+	case 'B':
+		bcmem = unittoull(ARGF());
+		break;
+	case 'c':
+		config = ARGF();
+		if(config == nil)
+			goto usage;
+		break;
+	case 'C':
+		mem = unittoull(ARGF());
+		break;
+	case 'd':
+		debug = 1;
+		break;
+	case 'h':
+		haddr = ARGF();
+		if(haddr == nil)
+			goto usage;
+		break;
+	case 'I':
+		icmem = unittoull(ARGF());
+		break;
+	case 'w':
+		queuewrites = 1;
+		break;
+	default:
+		goto usage;
+	}ARGEND
+
+print("whack %d\n", sizeof(Whack));
+
+	if(argc){
+  usage:
+		fprint(2, "usage: venti [-dw] [-a ventiaddress] [-h httpaddress] [-c config] [-C cachesize] [-I icachesize] [-B blockcachesize]\n");
+		threadexitsall("usage");
+	}
+
+	fmtinstall('V', vtscorefmt);
+	fmtinstall('H', encodefmt);
+	fmtinstall('F', vtfcallfmt);
+
+	if(config == nil)
+		config = "venti.conf";
+
+
+	if(initarenasum() < 0)
+		fprint(2, "warning: can't initialize arena summing process: %r");
+
+	if(initventi(config) < 0)
+		sysfatal("can't init server: %r");
+
+	if(mem == 0xffffffffUL)
+		mem = 1 * 1024 * 1024;
+	fprint(2, "initialize %d bytes of lump cache for %d lumps\n",
+		mem, mem / (8 * 1024));
+	initlumpcache(mem, mem / (8 * 1024));
+
+	icmem = u64log2(icmem / (sizeof(IEntry)+sizeof(IEntry*)) / ICacheDepth);
+	if(icmem < 4)
+		icmem = 4;
+	fprint(2, "initialize %d bytes of index cache for %d index entries\n",
+		(sizeof(IEntry)+sizeof(IEntry*)) * (1 << icmem) * ICacheDepth,
+		(1 << icmem) * ICacheDepth);
+	initicache(icmem, ICacheDepth);
+
+	/*
+	 * need a block for every arena and every process
+	 */
+	minbcmem = maxblocksize * 
+		(mainindex->narenas + mainindex->nsects*4 + 16);
+	if(bcmem < minbcmem)
+		bcmem = minbcmem;
+
+	fprint(2, "initialize %d bytes of disk block cache\n", bcmem);
+	initdcache(bcmem);
+
+	fprint(2, "sync arenas and index...\n");
+	if(syncindex(mainindex, 1) < 0)
+		sysfatal("can't sync server: %r");
+
+	if(queuewrites){
+		fprint(2, "initialize write queue...\n");
+		if(initlumpqueues(mainindex->nsects) < 0){
+			fprint(2, "can't initialize lump queues,"
+				" disabling write queueing: %r");
+			queuewrites = 0;
+		}
+	}
+
+	if(haddr){
+		fprint(2, "starting http server at %s\n", haddr);
+		if(httpdinit(haddr) < 0)
+			fprint(2, "warning: can't start http server: %r");
+	}
+
+	ventiserver(vaddr);
+	threadexitsall(0);
+}
+
+static void
+vtrerror(VtReq *r, char *error)
+{
+	r->rx.type = VtRerror;
+	r->rx.error = estrdup(error);
+}
+
+static void
+ventiserver(char *addr)
+{
+	Packet *p;
+	VtReq *r;
+	VtSrv *s;
+
+	s = vtlisten(addr);
+	if(s == nil)
+		sysfatal("can't announce %s: %r", addr);
+
+	while((r = vtgetreq(s)) != nil){
+		r->rx.type = r->tx.type+1;
+		print("req (arenas[0]=%p sects[0]=%p) %F\n",
+			mainindex->arenas[0], mainindex->sects[0], &r->tx);
+		switch(r->tx.type){
+		default:
+			vtrerror(r, "unknown request");
+			break;
+		case VtTread:
+			if((r->rx.data = readlump(r->tx.score, r->tx.dtype, r->tx.count)) == nil)
+				vtrerror(r, gerrstr());
+			break;
+		case VtTwrite:
+			p = r->tx.data;
+			r->tx.data = nil;
+			if(writelump(p, r->rx.score, r->tx.dtype, 0) < 0)	
+				vtrerror(r, gerrstr());
+			break;
+		case VtTsync:
+			queueflush();
+			break;
+		}
+		vtrespond(r);
+	}
+}
+
diff --git a/src/cmd/venti/verifyarena.c b/src/cmd/venti/verifyarena.c
new file mode 100644
index 00000000..9e7dc31b
--- /dev/null
+++ b/src/cmd/venti/verifyarena.c
@@ -0,0 +1,127 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+static int	verbose;
+
+void
+usage(void)
+{
+	fprint(2, "usage: verifyarena [-v]\n");
+	threadexitsall(0);
+}
+
+static void
+readblock(uchar *buf, int n)
+{
+	int nr, m;
+
+	for(nr = 0; nr < n; nr += m){
+		m = n - nr;
+		m = read(0, &buf[nr], m);
+		if(m <= 0)
+			sysfatal("can't read arena from standard input: %r");
+	}
+}
+
+static void
+verifyarena(void)
+{
+	Arena arena;
+	ArenaHead head;
+	ZBlock *b;
+	DigestState s;
+	u64int n, e;
+	u32int bs;
+	u8int score[VtScoreSize];
+
+	fprint(2, "verify arena from standard input\n");
+
+	memset(&arena, 0, sizeof arena);
+	memset(&s, 0, sizeof s);
+
+	/*
+	 * read the little bit, which will included the header
+	 */
+	bs = MaxIoSize;
+	b = alloczblock(bs, 0);
+	readblock(b->data, HeadSize);
+	sha1(b->data, HeadSize, nil, &s);
+	if(unpackarenahead(&head, b->data) < 0)
+		sysfatal("corrupted arena header: %r");
+	if(head.version != ArenaVersion)
+		fprint(2, "warning: unknown arena version %d\n", head.version);
+
+	/*
+	 * now we know how much to read
+	 * read everything but the last block, which is special
+	 */
+	e = head.size - head.blocksize;
+	for(n = HeadSize; n < e; n += bs){
+		if(n + bs > e)
+			bs = e - n;
+		readblock(b->data, bs);
+		sha1(b->data, bs, nil, &s);
+	}
+
+	/*
+	 * read the last block update the sum.
+	 * the sum is calculated assuming the slot for the sum is zero.
+	 */
+	bs = head.blocksize;
+	readblock(b->data, bs);
+	sha1(b->data, bs-VtScoreSize, nil, &s);
+	sha1(zeroscore, VtScoreSize, nil, &s);
+	sha1(nil, 0, score, &s);
+
+	/*
+	 * validity check on the trailer
+	 */
+	arena.blocksize = head.blocksize;
+	if(unpackarena(&arena, b->data) < 0)
+		sysfatal("corrupted arena trailer: %r");
+	scorecp(arena.score, &b->data[arena.blocksize - VtScoreSize]);
+
+	if(namecmp(arena.name, head.name) != 0)
+		sysfatal("arena header and trailer names clash: %s vs. %s\n", head.name, arena.name);
+	if(arena.version != head.version)
+		sysfatal("arena header and trailer versions clash: %d vs. %d\n", head.version, arena.version);
+	arena.size = head.size - 2 * head.blocksize;
+
+	/*
+	 * check for no checksum or the same
+	 */
+	if(scorecmp(score, arena.score) != 0){
+		if(scorecmp(zeroscore, arena.score) != 0)
+			fprint(2, "warning: mismatched checksums for arena=%s, found=%V calculated=%V",
+				arena.name, arena.score, score);
+		scorecp(arena.score, score);
+	}else
+		fprint(2, "matched score\n");
+
+	printarena(2, &arena);
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	fmtinstall('V', vtscorefmt);
+	statsinit();
+
+	ARGBEGIN{
+	case 'v':
+		verbose++;
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	readonly = 1;
+
+	if(argc != 0)
+		usage();
+
+	verifyarena();
+	threadexitsall(0);
+}
diff --git a/src/cmd/venti/whack.c b/src/cmd/venti/whack.c
new file mode 100644
index 00000000..9aa6b6d2
--- /dev/null
+++ b/src/cmd/venti/whack.c
@@ -0,0 +1,330 @@
+#include "stdinc.h"
+#include "whack.h"
+
+typedef struct Huff	Huff;
+
+enum
+{
+	MaxFastLen	= 9,
+	BigLenCode	= 0x1f4,	/* minimum code for large lenth encoding */
+	BigLenBits	= 9,
+	BigLenBase	= 4,		/* starting items to encode for big lens */
+
+	MinOffBits	= 6,
+	MaxOffBits	= MinOffBits + 8,
+
+	MaxLen		= 2051		/* max. length encodable in 24 bits */
+};
+
+enum
+{
+	StatBytes,
+	StatOutBytes,
+	StatLits,
+	StatMatches,
+	StatLitBits,
+	StatOffBits,
+	StatLenBits,
+
+	MaxStat
+};
+
+struct Huff
+{
+	short	bits;				/* length of the code */
+	ulong	encode;				/* the code */
+};
+
+static	Huff	lentab[MaxFastLen] =
+{
+	{2,	0x2},		/* 10 */
+	{3,	0x6},		/* 110 */
+	{5,	0x1c},		/* 11100 */
+	{5,	0x1d},		/* 11101 */
+	{6,	0x3c},		/* 111100 */
+	{7,	0x7a},		/* 1111010 */
+	{7,	0x7b},		/* 1111011 */
+	{8,	0xf8},		/* 11111000 */
+	{8,	0xf9},		/* 11111001 */
+};
+
+static int	thwmaxcheck;
+
+void
+whackinit(Whack *tw, int level)
+{
+	thwmaxcheck = (1 << level);
+	thwmaxcheck -= thwmaxcheck >> 2;
+	if(thwmaxcheck < 2)
+		thwmaxcheck = 2;
+	else if(thwmaxcheck > 1024)
+		thwmaxcheck = 1024;
+	memset(tw, 0, sizeof *tw);
+	tw->begin = 2 * WhackMaxOff;
+}
+
+/*
+ * find a string in the dictionary
+ */
+static int
+whackmatch(Whack *b, uchar **ss, uchar *esrc, ulong h, ulong now)
+{
+	ushort then, off, last;
+	int bestoff, bestlen, check;
+	uchar *s, *t;
+
+	s = *ss;
+	if(esrc < s + MinMatch)
+		return -1;
+	if(s + MaxLen < esrc)
+		esrc = s + MaxLen;
+
+	bestoff = 0;
+	bestlen = 0;
+	check = thwmaxcheck;
+	last = 0;
+	for(then = b->hash[h]; check-- > 0; then = b->next[then & (WhackMaxOff - 1)]){
+		off = now - then;
+		if(off <= last || off > WhackMaxOff)
+			break;
+
+		/*
+		 * don't need to check for the end because
+		 * 1) s too close check above
+		 */
+		t = s - off;
+		if(s[0] == t[0] && s[1] == t[1] && s[2] == t[2]){
+			if(!bestlen || esrc - s > bestlen && s[bestlen] == t[bestlen]){
+				t += 3;
+				for(s += 3; s < esrc; s++){
+					if(*s != *t)
+						break;
+					t++;
+				}
+				if(s - *ss > bestlen){
+					bestlen = s - *ss;
+					bestoff = off;
+					if(bestlen > thwmaxcheck)
+						break;
+				}
+			}
+		}
+		s = *ss;
+		last = off;
+	}
+	*ss += bestlen;
+	return bestoff;
+}
+
+/*
+ * knuth vol. 3 multiplicative hashing
+ * each byte x chosen according to rules
+ * 1/4 < x < 3/10, 1/3 x < < 3/7, 4/7 < x < 2/3, 7/10 < x < 3/4
+ * with reasonable spread between the bytes & their complements
+ *
+ * the 3 byte value appears to be as almost good as the 4 byte value,
+ * and might be faster on some machines
+ */
+/*
+#define hashit(c)	((((ulong)(c) * 0x6b43a9) >> (24 - HashLog)) & HashMask)
+*/
+#define hashit(c)	(((((ulong)(c) & 0xffffff) * 0x6b43a9b5) >> (32 - HashLog)) & HashMask)
+
+/*
+ * lz77 compression with single lookup in a hash table for each block
+ */
+int
+whack(Whack *w, uchar *dst, uchar *src, int n, ulong stats[WhackStats])
+{
+	uchar *s, *ss, *sss, *esrc, *half, *wdst, *wdmax;
+	ulong cont, code, wbits;
+	ushort now;
+	int toff, lithist, h, len, bits, use, wnbits, lits, matches, offbits, lenbits;
+
+	if(n < MinMatch)
+		return -1;
+
+	wdst = dst;
+	wdmax = dst + n;
+
+	now = w->begin;
+	s = src;
+	w->data = s;
+
+	cont = (s[0] << 16) | (s[1] << 8) | s[2];
+
+	esrc = s + n;
+	half = s + (n >> 1);
+	wnbits = 0;
+	wbits = 0;
+	lits = 0;
+	matches = 0;
+	offbits = 0;
+	lenbits = 0;
+	lithist = ~0;
+	while(s < esrc){
+		h = hashit(cont);
+
+		sss = s;
+		toff = whackmatch(w, &sss, esrc, h, now);
+		ss = sss;
+
+		len = ss - s;
+		for(; wnbits >= 8; wnbits -= 8){
+			if(wdst >= wdmax){
+				w->begin = now;
+				return -1;
+			}
+			*wdst++ = wbits >> (wnbits - 8);
+		}
+		if(len < MinMatch){
+			toff = *s;
+			lithist = (lithist << 1) | toff < 32 | toff > 127;
+			if(lithist & 0x1e){
+				wbits = (wbits << 9) | toff;
+				wnbits += 9;
+			}else if(lithist & 1){
+				toff = (toff + 64) & 0xff;
+				if(toff < 96){
+					wbits = (wbits << 10) | toff;
+					wnbits += 10;
+				}else{
+					wbits = (wbits << 11) | toff;
+					wnbits += 11;
+				}
+			}else{
+				wbits = (wbits << 8) | toff;
+				wnbits += 8;
+			}
+			lits++;
+
+			/*
+			 * speed hack
+			 * check for compression progress, bail if none achieved
+			 */
+			if(s > half){
+				if(4 * (s - src) < 5 * lits){
+					w->begin = now;
+					return -1;
+				}
+				half = esrc;
+			}
+
+			if(s + MinMatch <= esrc){
+				w->next[now & (WhackMaxOff - 1)] = w->hash[h];
+				w->hash[h] = now;
+				if(s + MinMatch < esrc)
+					cont = (cont << 8) | s[MinMatch];
+			}
+			now++;
+			s++;
+			continue;
+		}
+
+		matches++;
+
+		/*
+		 * length of match
+		 */
+		if(len > MaxLen){
+			len = MaxLen;
+			ss = s + len;
+		}
+		len -= MinMatch;
+		if(len < MaxFastLen){
+			bits = lentab[len].bits;
+			wbits = (wbits << bits) | lentab[len].encode;
+			wnbits += bits;
+			lenbits += bits;
+		}else{
+			code = BigLenCode;
+			bits = BigLenBits;
+			use = BigLenBase;
+			len -= MaxFastLen;
+			while(len >= use){
+				len -= use;
+				code = (code + use) << 1;
+				use <<= (bits & 1) ^ 1;
+				bits++;
+			}
+
+			wbits = (wbits << bits) | (code + len);
+			wnbits += bits;
+			lenbits += bits;
+
+			for(; wnbits >= 8; wnbits -= 8){
+				if(wdst >= wdmax){
+					w->begin = now;
+					return -1;
+				}
+				*wdst++ = wbits >> (wnbits - 8);
+			}
+		}
+
+		/*
+		 * offset in history
+		 */
+		toff--;
+		for(bits = MinOffBits; toff >= (1 << bits); bits++)
+			;
+		if(bits < MaxOffBits-1){
+			wbits = (wbits << 3) | (bits - MinOffBits);
+			if(bits != MinOffBits)
+				bits--;
+			wnbits += bits + 3;
+			offbits += bits + 3;
+		}else{
+			wbits = (wbits << 4) | 0xe | (bits - (MaxOffBits-1));
+			bits--;
+			wnbits += bits + 4;
+			offbits += bits + 4;
+		}
+		wbits = (wbits << bits) | toff & ((1 << bits) - 1);
+
+		for(; s != ss; s++){
+			if(s + MinMatch <= esrc){
+				h = hashit(cont);
+				w->next[now & (WhackMaxOff - 1)] = w->hash[h];
+				w->hash[h] = now;
+				if(s + MinMatch < esrc)
+					cont = (cont << 8) | s[MinMatch];
+			}
+			now++;
+		}
+	}
+
+	w->begin = now;
+
+	stats[StatBytes] += esrc - src;
+	stats[StatLits] += lits;
+	stats[StatMatches] += matches;
+	stats[StatLitBits] += (wdst - (dst + 2)) * 8 + wnbits - offbits - lenbits;
+	stats[StatOffBits] += offbits;
+	stats[StatLenBits] += lenbits;
+
+	if(wnbits & 7){
+		wbits <<= 8 - (wnbits & 7);
+		wnbits += 8 - (wnbits & 7);
+	}
+	for(; wnbits >= 8; wnbits -= 8){
+		if(wdst >= wdmax)
+			return -1;
+		*wdst++ = wbits >> (wnbits - 8);
+	}
+
+	stats[StatOutBytes] += wdst - dst;
+
+	return wdst - dst;
+}
+
+int
+whackblock(uchar *dst, uchar *src, int ssize)
+{
+	Whack w;
+	ulong stats[MaxStat];
+	int r;
+
+	whackinit(&w, 6);
+	r = whack(&w, dst, src, ssize, stats);
+	return r;
+}
diff --git a/src/cmd/venti/whack.h b/src/cmd/venti/whack.h
new file mode 100644
index 00000000..fb966169
--- /dev/null
+++ b/src/cmd/venti/whack.h
@@ -0,0 +1,40 @@
+typedef struct Whack		Whack;
+typedef struct Unwhack		Unwhack;
+
+enum
+{
+	WhackStats	= 8,
+	WhackErrLen	= 64,		/* max length of error message from thwack or unthwack */
+	WhackMaxOff	= 16*1024,	/* max allowed offset */
+
+	HashLog		= 14,
+	HashSize	= 1<<HashLog,
+	HashMask	= HashSize - 1,
+
+	MinMatch	= 3,		/* shortest match possible */
+
+	MinDecode	= 8,		/* minimum bits to decode a match or lit; >= 8 */
+
+	MaxSeqMask	= 8,		/* number of bits in coding block mask */
+	MaxSeqStart	= 256		/* max offset of initial coding block */
+};
+
+struct Whack
+{
+	ushort		begin;			/* time of first byte in hash */
+	ushort		hash[HashSize];
+	ushort		next[WhackMaxOff];
+	uchar		*data;
+};
+
+struct Unwhack
+{
+	char		err[WhackErrLen];
+};
+
+void	whackinit(Whack*, int level);
+void	unwhackinit(Unwhack*);
+int	whack(Whack*, uchar *dst, uchar *src, int nsrc, ulong stats[WhackStats]);
+int	unwhack(Unwhack*, uchar *dst, int ndst, uchar *src, int nsrc);
+
+int	whackblock(uchar *dst, uchar *src, int ssize);
diff --git a/src/cmd/venti/wrarena.c b/src/cmd/venti/wrarena.c
new file mode 100644
index 00000000..f232928a
--- /dev/null
+++ b/src/cmd/venti/wrarena.c
@@ -0,0 +1,148 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+char *host;
+int readonly = 1;	/* for part.c */
+
+void
+usage(void)
+{
+	fprint(2, "usage: wrarena [-h host] arenafile [offset]\n");
+	threadexitsall("usage");
+}
+
+static void
+rdarena(VtConn *z, Arena *arena, u64int offset)
+{
+	u64int a, aa, e;
+	u32int magic;
+	Clump cl;
+	uchar score[VtScoreSize];
+	ZBlock *lump;
+
+	fprint(2, "copying %s to venti\n", arena->name);
+	printarena(2, arena);
+
+	a = arena->base;
+	e = arena->base + arena->size;
+	if(offset != ~(u64int)0) {
+		if(offset >= e-a)
+			sysfatal("bad offset %llud >= %llud\n",
+				offset, e-a);
+		aa = offset;
+	} else
+		aa = 0;
+
+	for(; aa < e; aa += ClumpSize+cl.info.size) {
+		magic = clumpmagic(arena, aa);
+		if(magic == ClumpFreeMagic)
+			break;
+		if(magic != ClumpMagic) {
+			fprint(2, "illegal clump magic number %#8.8ux offset %llud\n",
+				magic, aa);
+			break;
+		}
+		lump = loadclump(arena, aa, 0, &cl, score, 0);
+		if(lump == nil) {
+			fprint(2, "clump %llud failed to read: %r\n", aa);
+			break;
+		}
+		if(cl.info.type != VtTypeCorrupt) {
+			scoremem(score, lump->data, cl.info.uncsize);
+			if(scorecmp(cl.info.score, score) != 0) {
+				fprint(2, "clump %llud has mismatched score\n", aa);
+				break;
+			}
+			if(vttypevalid(cl.info.type) < 0) {
+				fprint(2, "clump %llud has bad type %d\n", aa, cl.info.type);
+				break;
+			}
+		}
+		if(z && vtwrite(z, score, cl.info.type, lump->data, cl.info.uncsize) < 0)
+			sysfatal("failed writing clump %llud: %r", aa);
+		freezblock(lump);
+	}
+	if(z && vtsync(z) < 0)
+		sysfatal("failed executing sync: %r");
+
+	print("end offset %llud\n", aa);
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	char *file;
+	VtConn *z;
+	Arena *arena;
+	u64int offset, aoffset;
+	Part *part;
+	Dir *d;
+	uchar buf[8192];
+	ArenaHead head;
+
+	aoffset = 0;
+	ARGBEGIN{
+	case 'h':
+		host = EARGF(usage());
+		break;
+	case 'o':
+		aoffset = strtoull(EARGF(usage()), 0, 0);
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	offset = ~(u64int)0;
+	switch(argc) {
+	default:
+		usage();
+	case 2:
+		offset = strtoull(argv[1], 0, 0);
+		/* fall through */
+	case 1:
+		file = argv[0];
+	}
+
+
+	fmtinstall('V', vtscorefmt);
+
+	statsinit();
+
+	if((d = dirstat(file)) == nil)
+		sysfatal("can't stat file %s: %r", file);
+
+	part = initpart(file, 0);
+	if(part == nil)
+		sysfatal("can't open file %s: %r", file);
+	if(readpart(part, aoffset, buf, sizeof buf) < 0)
+		sysfatal("can't read file %s: %r", file);
+
+	if(unpackarenahead(&head, buf) < 0)
+		sysfatal("corrupted arena header: %r");
+
+	if(aoffset+head.size > d->length)
+		sysfatal("arena is truncated: want %llud bytes have %llud\n",
+			head.size, d->length);
+
+	partblocksize(part, head.blocksize);
+	initdcache(8 * MaxDiskBlock);
+
+	arena = initarena(part, aoffset, head.size, head.blocksize);
+	if(arena == nil)
+		sysfatal("initarena: %r");
+
+	if(host && strcmp(host, "/dev/null") != 0){
+		z = vtdial(host);
+		if(z == nil)
+			sysfatal("could not connect to server: %r");
+		if(vtconnect(z) < 0)
+			sysfatal("vtconnect: %r");
+	}else
+		z = nil;
+	
+	rdarena(z, arena, offset);
+	vthangup(z);
+	threadexitsall(0);
+}
diff --git a/src/cmd/venti/write.c b/src/cmd/venti/write.c
new file mode 100644
index 00000000..94b61be4
--- /dev/null
+++ b/src/cmd/venti/write.c
@@ -0,0 +1,60 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+char *host;
+
+void
+usage(void)
+{
+	fprint(2, "usage: write [-z] [-h host] [-t type] <datablock\n");
+	threadexitsall("usage");
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	uchar *p, score[VtScoreSize];
+	int type, n, dotrunc;
+	VtConn *z;
+
+	dotrunc = 0;
+	type = VtDataType;
+	ARGBEGIN{
+	case 'z':
+		dotrunc = 1;
+		break;
+	case 'h':
+		host = EARGF(usage());
+		break;
+	case 't':
+		type = atoi(EARGF(usage()));
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	if(argc != 0)
+		usage();
+
+
+	fmtinstall('V', vtscorefmt);
+
+	p = ezmalloc(VtMaxLumpSize+1);
+	n = readn(0, p, VtMaxLumpSize+1);
+	if(n > VtMaxLumpSize)
+		sysfatal("data too big");
+	z = vtdial(host);
+	if(z == nil)
+		sysfatal("could not connect to server: %r");
+	if(vtconnect(z) < 0)
+		sysfatal("vtconnect: %r");
+	if(dotrunc)
+		n = vtzerotruncate(type, p, n);
+	if(vtwrite(z, score, type, p, n) < 0)
+		sysfatal("vtwrite: %r");
+	vthangup(z);
+	print("%V\n", score);
+	threadexitsall(0);
+}
diff --git a/src/cmd/venti/xml.c b/src/cmd/venti/xml.c
new file mode 100644
index 00000000..d50d5bc9
--- /dev/null
+++ b/src/cmd/venti/xml.c
@@ -0,0 +1,69 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+#include "httpd.h"
+#include "xml.h"
+
+void xmlarena(Hio *hout, Arena *s, char *tag, int indent){
+	xmlindent(hout, indent);
+	hprint(hout, "<%s", tag);
+	xmlaname(hout, s->name, "name");
+	xmlu32int(hout, s->version, "version");
+	xmlaname(hout, s->part->name, "partition");
+	xmlu32int(hout, s->blocksize, "blocksize");
+	xmlu64int(hout, s->base, "start");
+	xmlu64int(hout, s->base+2*s->blocksize, "stop");
+	xmlu32int(hout, s->ctime, "created");
+	xmlu32int(hout, s->wtime, "modified");
+	xmlsealed(hout, s->sealed, "sealed");
+	xmlscore(hout, s->score, "score");
+	xmlu32int(hout, s->clumps, "clumps");
+	xmlu32int(hout, s->cclumps, "compressedclumps");
+	xmlu64int(hout, s->uncsize, "data");
+	xmlu64int(hout, s->used - s->clumps * ClumpSize, "compresseddata");
+	xmlu64int(hout, s->used + s->clumps * ClumpInfoSize, "storage");
+	hprint(hout, "/>\n");
+}
+
+void xmlindex(Hio *hout, Index *s, char *tag, int indent){
+	int i;
+	xmlindent(hout, indent);
+	hprint(hout, "<%s", tag);
+	xmlaname(hout, s->name, "name");
+	xmlu32int(hout, s->version, "version");
+	xmlu32int(hout, s->blocksize, "blocksize");
+	xmlu32int(hout, s->tabsize, "tabsize");
+	xmlu32int(hout, s->buckets, "buckets");
+	xmlu32int(hout, s->div, "buckdiv");
+	hprint(hout, ">\n");
+	xmlindent(hout, indent + 1);
+	hprint(hout, "<sects>\n");
+	for(i = 0; i < s->nsects; i++)
+		xmlamap(hout, &s->smap[i], "sect", indent + 2);
+	xmlindent(hout, indent + 1);
+	hprint(hout, "</sects>\n");
+	xmlindent(hout, indent + 1);
+	hprint(hout, "<amaps>\n");
+	for(i = 0; i < s->narenas; i++)
+		xmlamap(hout, &s->amap[i], "amap", indent + 2);
+	xmlindent(hout, indent + 1);
+	hprint(hout, "</amaps>\n");
+	xmlindent(hout, indent + 1);
+	hprint(hout, "<arenas>\n");
+	for(i = 0; i < s->narenas; i++)
+		xmlarena(hout, s->arenas[i], "arena", indent + 2);
+	xmlindent(hout, indent + 1);
+	hprint(hout, "</arenas>\n");
+	xmlindent(hout, indent);
+	hprint(hout, "</%s>\n", tag);
+}
+
+void xmlamap(Hio *hout, AMap *s, char *tag, int indent){
+	xmlindent(hout, indent);
+	hprint(hout, "<%s", tag);
+	xmlaname(hout, s->name, "name");
+	xmlu64int(hout, s->start, "start");
+	xmlu64int(hout, s->stop, "stop");
+	hprint(hout, "/>\n");
+}
+
diff --git a/src/cmd/venti/xml.h b/src/cmd/venti/xml.h
new file mode 100644
index 00000000..c9e52b0b
--- /dev/null
+++ b/src/cmd/venti/xml.h
@@ -0,0 +1,11 @@
+void	xmlamap(Hio *hout, AMap *v, char *tag, int indent);
+void	xmlarena(Hio *hout, Arena *v, char *tag, int indent);
+void	xmlindex(Hio *hout, Index *v, char *tag, int indent);
+
+void	xmlaname(Hio *hout, char *v, char *tag);
+void	xmlscore(Hio *hout, u8int *v, char *tag);
+void	xmlsealed(Hio *hout, int v, char *tag);
+void	xmlu32int(Hio *hout, u32int v, char *tag);
+void	xmlu64int(Hio *hout, u64int v, char *tag);
+
+void	xmlindent(Hio *hout, int indent);
diff --git a/src/cmd/venti/zeropart.c b/src/cmd/venti/zeropart.c
new file mode 100644
index 00000000..b24c98c6
--- /dev/null
+++ b/src/cmd/venti/zeropart.c
@@ -0,0 +1,28 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+void
+zeropart(Part *part, int blocksize)
+{
+	ZBlock *b;
+	u64int addr;
+	int w;
+
+	fprint(2, "clearing the partition\n");
+
+	b = alloczblock(MaxIoSize, 1);
+
+	w = 0;
+	for(addr = PartBlank; addr + MaxIoSize <= part->size; addr += MaxIoSize){
+		if(writepart(part, addr, b->data, MaxIoSize) < 0)
+			sysfatal("can't initialize %s, writing block %d failed: %r", part->name, w);
+		w++;
+	}
+
+	for(; addr + blocksize <= part->size; addr += blocksize)
+		if(writepart(part, addr, b->data, blocksize) < 0)
+			sysfatal("can't initialize %s: %r", part->name);
+
+	freezblock(b);
+}