Path: utzoo!utgpu!water!watmath!clyde!rutgers!ucla-cs!cit-vax!elroy!ames!sdcsvax!ucsdhub!hp-sdd!hplabs!hpda!hpesoc1!hpindda!hpcupt1!hpirs!runyan
From: runyan@hpirs.HP.COM (Mark Runyan)
Newsgroups: comp.unix.questions
Subject: Re: SCCS vs. RCS
Message-ID: <4750011@hpirs.HP.COM>
Date: 26 Jan 88 20:01:20 GMT
References: <720003@hpclskh.HP.COM>
Organization: Hewlett Packard, Cupertino
Lines: 28

>/ gwyn@brl-smoke.ARPA (Doug Gwyn ) /  3:08 am  Jan 14, 1988 /
>In article <720003@hpclskh.HP.COM> skh@hpclskh.HP.COM writes:
>>My only comment to you would be this:  the versions of SCCS I have seen
>>store the original source file and differences from that file.  RCS versions
>>tend to store the latest source file and differences from previous versions.
>
>SCCS archives are not the way you describe.

Perhaps what he said was a little too general, but that is a quick
explanation.  A better was is to say that SCCS stores the original
and the interleaves the deltas when a check in is done.  This means
that the "get" must always scan the entire file to retrieve a document
no matter how far back you go.

>>This means that SCCS takes longer to give the the latest version of a file;
>>RCS takes longer to get back to a previous version.
>
>Since SCCS "get" does not in fact have to apply each delta separately, but
>rather applies them all in one sequential scan, it is fairly fast.
>
>It takes SCCS "get" about a second on a VAX-11/780 to retrieve the latest
>version of a 1000-line program that has undergone from 4 to 10 revisions.

The retrieval of a file in SCCS vs the speed of retrieval in RCS has been
much debated, with different values always stated.  Perhaps someone would
care to derive a table of values on different machines? :-)

Mark Runyan  ( RCS Warrior )