Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!morocco!landauer From: landauer@morocco.Sun.COM (Doug Landauer) Newsgroups: comp.unix.questions Subject: Re: RCS and SCCS (and CMS) Keywords: CMS RCS SCCS Message-ID: <58292@sun.uucp> Date: 28 Jun 88 21:25:47 GMT References: <890@fig.bbn.com> <710@ubu.warwick.UUCP> <1134@cod.NOSC.MIL> Sender: news@sun.uucp Reply-To: landauer@sun.UUCP (Doug Landauer) Organization: Sun Microsystems, Mountain View Lines: 60 In article <1134@cod.NOSC.MIL>, dberg@cod.NOSC.MIL (David I. Berg) wrote: > Another feature of RCS is that it stores the current > version of your file and the changes backward to the original, whereas > SCCS stores the original version of your file and the changes forward > to the current. This is a common misconception (oversimplification) -- it implies that it could take significantly longer using SCCS to get the current version of the file than for it to get the original version. In fact, SCCS does not store separate deltas; it stores all of the deltas together, in the appropriate places within "the original file", in the file in such a way that it takes about the same amount of time to get any version. There are several barely relevant performance implications of the differences between this scheme and what RCS does: + for RCS: For retrieving the latest version (RCS is betting that this is the most common case), RCS is likely to be faster; ~ : For retrieving any other versions, RCS slows down relative to its own performance on the latest version (and at some point depending on how many deltas as well as how many lines changed per delta, it may be slower than SCCS); + for SCCS: Doing RCS check-ins (storing new versions) should be distinctly slower than doing SCCS deltas; > I find RCS particularly easier to use than SCCS. I personally agree with this statement (disclaimer: Sun doesn't officially agree). The BSD "sccs" front-end command helps some. Finally, the performance differences mentioned above probably add up (over the course of my entire SCCS career) to less time than I spent composing this message (as David I. Berg put it, "it will take SCCS a trifle longer"), so the ease-of-use factor should become the overriding factor if you're starting a new project in a new company or on your own. In practice, the "what-they-use-here" factor is the real overriding factor. This is one of the few areas where VMS (gasp!) really does do better than Unix (IMHO) -- DEC's CMS (though it has brain damage in some ways) really does have some features that would make it, on the whole, better than either SCCS or RCS, if you could use it on Unix instead of VMS. -- Doug Landauer Sun Microsystems, Inc. ARPA Internet: landauer@sun.com Software Products Division UUCP: ...!sun!landauer -- Acronym glossary: (Some of these are trademarks -- you know who you are.) BSD -- Berkeley Software Distribution CMS -- Code Management System (I think) DEC -- Digital Equipment Corporation IMHO -- In My Humble Opinion RCS -- Revision Control System SCCS -- Source Code Control System UUCP -- Unix-to-Unix CoPy VMS -- Virtual Memory System (an operating system for some DEC computers) --