From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <2e17f5911f28043ad02f29b7feac785e@terzarima.net>
From: Charles Forsyth <forsyth@terzarima.net>
Date: Wed,  5 Mar 2008 08:43:40 +0000
To: weigelt@metux.de, 9fans@cse.psu.edu
Subject: Re: [9fans] thoughs about venti+fossil
In-Reply-To: <20080305040019.GA13663@nibiru.local>
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>1. how stable is the keying ? sha-1 has only 160 bits, while
>   data blocks may be up to 56k long. so, the mapping is only
>   unique into one direction (not one-to-one). how can we be
>   *really sure*, that - even on very large storages (TB or
>   even PB) - data to each key is alway (one-to-one) unique ?

on a write, the computer will tell you if you ought to have bought
that lottery ticket and stayed out of the rain:

	u = lookuplump(score, type);
	if(u->data != nil){
		...
		if(packetcmp(p, u->data) != 0){
			...
			if(scorecmp(u->score, score) != 0)
				seterr(EStrange, "lookuplump returned bad score %V not %V", u->score, score);
			else if(scorecmp(u->score, nscore) != 0)
				seterr(EStrange, "lookuplump returned bad data %V not %V", nscore, u->score);
			else
				seterr(EStrange, "score collision %V", score);