RCS and SCCS

[Joel Clark]

In article <661 at pyuxe.UUCP> mayerar at pyuxe.UUCP (80132-A Mayer) writes:
>In article <710 at ubu.warwick.UUCP> maujd at warwick.UUCP (Geoff Rimmer) writes:
>>Which out of RCS and SCCS do people prefer?  
>>
>>Geoff.
>
>One good point of RCS is that it stores the most recent version and 
>uses deltas to get back to the previous versions.  SCCS stores the
>original version and uses deltas to get to the most recent version.
>
>		Andrew J. Mayer
>		BELLCORE
>
>{ariel,burl,clyde,floyd,gamma,harpo,ihnp4,mhuxl,rutgers}!pyuxe!mayerar

Even though I have written software with similar functionality as SCCS,
I have never understood this argument about storing the most recent
version as opposed to storing the original version.  For example given
the following actual SCCS file:


I 1
/*
 * module control port settings
 */
D 2
#define NPGM_DONE	0x01
E 2
I 2
#define RRCV		0x02
E 2
#define RLSRCV		0x02
#define	NPROGRAM	0x80
E 1

We see the original and the most recent stored in the same manor, line
by line.  Any program trying to a extract version still has to look at 
every line to decide if that line is in the desired version or not.

Can anyone explain to me how a program could store `the most recent version`
such that each line in the file does not need to be examined to determine
if it is in the most recent version?

Joel Clark
Intel Scientific Computers			joel at intelisc.uucp.com
Beaverton, OR				{tektronix}!ogcvax!intelisc!joel
(503) 629 7732