RCS vs SCCS (RESULTS - LONG)

Ken Arnold%CGL arnold at ucsfcgl.UUCP
Thu May 9 10:53:25 AEST 1985


>From: Craig Partridge <umcp-cs!seismo!craig at loki.ARPA>
>	(3) RCS is faster.  RCS stores diffs to take you back from the
>	most recent edition of the source.  SCCS stores changes forward
>	from the first version.  So in SCCS you wait a while for
>	your current file to retrieved.  In RCS there is no wait.

This is a common piece of misinformation.  RCS does store backward
delta's, i.e., it stores the current version intact, and has deltas
backwards to get earlier version.  However, SCCS does NOT store forward
deltas from the original.  It uses in-line deltas, giving a fixed
one-pass overhead to get different deltas.  Thus, getting the current
version is slightly slower (I believe the figure is around 5% slower
than RCS), but getting the version one delta back (for doing a diff,
say), SCCS is faster by a small amount, and for anything more than one
delta, SCCS is MUCH faster.

In other words, to get a delta N deltas back from the top, it takes one
pass for SCCS and N passes for RCS.

None the less, I do prefer RCS, as you know if you read father into the
summary to get my comments.  This particular piece of "slander" against
SCCS should be cleared up.  It is unfortunate that RCS doesn't use this
technique.



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