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From: runyan@hpcuhc.HP.COM (Mark Runyan)
Newsgroups: comp.unix.questions
Subject: Re: SCCS misinformation Rumor-Control (was Re: RCS vs. SCCS)
Message-ID: <250005@hpcuhc.HP.COM>
Date: 21 Mar 90 20:10:24 GMT
References: <1990Mar20.172303.7647@iwarp.intel.com>
Organization: HP GSY/USO/UKL Cupertino, CA, USA
Lines: 25

>/ guy@auspex.auspex.com (Guy Harris) /  5:41 pm  Mar 20, 1990 /
>> Mike Segel writes:
>>   SCCS uses forward deltas. This means that when you "check in"
>>   a piece of code, the original is stored, and the later copies
>>   are really deltas based on the original.
>
>This is not correct.  SCCS does not use forward deltas.  As Mark Runyan
>stated in his posting:
>
>| I write:
>|  7. RCS stores its revisions so retrieval of the latest revision is quick
>|     and easy, but early revisions take longer.  SCCS stores revisions so
>|     that recovering any given revision takes a constant amount of time which
>|     increases with the number of revisions stored.

I thought I made it clear and I'm glad Guy pointed it out again.  I've
heard many people refer to SCCS's method as using forward deltas, but it
doesn't.  Perhaps if you look at it sideways you could call it forward deltas,
but I think you are misrepresenting it if you do.  It really stores a set
of tagged lines (as another poster pointed out).  The only point being that
RCS is fast on the *latest* revision and slow for past revisions while SCCS
takes a "virtually" constant amount of time for any given revision but that
time increases with the number of revisions.  

Mark Runyan