Talk:List of version-control software
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Untitled
[edit]I will erase the cleanup, what exactly neads to be cleaned up right now? Moa3333 13:15, May 14, 2005 (UTC)
So what happened? It's 2013.. 78.141.139.10 (talk) 15:45, 19 March 2013 (UTC)
CVSNT wasn't in the list.
[edit]Considering that CVSNT started back in 1999, while SVN started in 2004. (not to mention other cool things about CVSNT.)
thats messed up, haha. ---Fractal3 00:35, 12 April 2006 (UTC)
Files-11
[edit]Should OpenVMS's Files-11 be included? — Preceding unsigned comment added by 80.58.1.42 (talk) 14:53, 5 July 2005 (UTC)
order of programs
[edit]is it by popularity? chronology? it sure isn't alphabetical, but I think a clear well-defined order is fine as long as it adds something to the reference. — Preceding unsigned comment added by 71.103.107.250 (talk) 22:25, 8 July 2005 (UTC)
- Agreed. Since chronology and popularity are both too hard to research and prove, I would vote for alphabetical within each category. Next time I'm back on this page, if nobody has objected, I'll probably do it. - kevins
Evolution description fair?
[edit]Article says "Evolution, (available here), simply better SCM and digital asset management" - isn't this a bit point-of-view (the "simply better" part)? Or is it their slogan? Peter S. 09:45, 20 August 2005 (UTC)
- I agree with the above comment. I see the extended description for Evolution was removed, and then reinstated. My opinion is that the current extended description is advertising that does not reflect a neutral point of view and should be reverted. --Seitz 07:42, 7 September 2005 (UTC)
- The Evolution description seems to qualify as spam:
"Adding a link that's snazzier than any of the others. If there's a list of products that gives just their names, and you add a product with a short blurb about how great it is, we'll all know why you did it."--Seitz 08:26, 7 September 2005 (UTC)
"Simply better" was/is one of the slogans associated with Evolution. The listing has been updated though and no longer contains this text.
patch management software
[edit]I think quilt isn't a true version control software but rather tool for managing set of patches. Citing Patchwork Quilt's homepage: "The scripts allow to manage a series of patches by keeping track of the changes each patch makes. Patches can be applied, un-applied, refreshed, etc."
From other point of view, if you chose to list here patch management software, why no mention of other such systems, e.g. dpatch? This is unfair :).
After all I must say that quilt is quite (if not very) mature and functional at the moment. Several Debian projects use quilt (and prefer it over abovementioned dpatch) for keeping Debian's separately from Caesar^H^H^H^H^H^Hupstream's. --Xrgtn 13:34, 16 January 2006 (UTC)
SCCS categorization
[edit]I don't think it's correct to list SCCS as "Proprietary: Server based":
- SCCS started as proprietary. But the command set is now part of the UNIX standard, and FreeBSD includes an implementation.
- SCCS simply operates on files, it doesn't have a repository server.
- SCCS is OpenSource sccs.berlios.de. The current version does not include server support but this is going to change with SCCS revision 6.0. --Schily (talk) 13:15, 20 June 2011 (UTC)
Marketing pitches
[edit]I think describing products as fast and/or easy to use is too subjective and should be removed. The latest such edit: "Mercurial — written in Python. Extremely fast, lightweight, portable, and easy to use." After removing marketing hype should read, "Mercurial — written in Python. Portable." -- Bartosz 20:31, 28 April 2006 (UTC)
This problem is getting worse. Phrases like "next generation" or "powerful" have no place in Wikipedia. They are meaningless marketing hype. -- Bartosz 19:28, 7 June 2006 (UTC)
- I definitely agree that phrases like "advanced", "powerful", and "next generation" are mostly meaningless. I've gone through the article and removed some of the claims that looked like hype to me.
- However, I think we need to be careful not to remove information. Some tools really are easier to use, more portable, or more lightweight than others. I don't think we should to water down all the claims to to eliminate any controversy, at the expense of providing a useful comparison. Wmahan. 16:12, 10 June 2006 (UTC)
- It's true that some products are easier to use than other and it would be helpful to rank them. The problem is: Who would do this ranking? As for portability, just listing the platforms is good enough and it's objective. --- Bartosz 02:17, 13 June 2006 (UTC)
Also what is CVSNT doing in the 'widely used and accepted' section?! I don't think it's any more widely used than the other obscure ones or am I missing something? And if they've been at it since 1999...
I just removed reference to Perforce having a 'scalable' client-server architecture - without categorising scalable in this context it's just marketing. Also, Perforce doesn't seem to be scalling very well in our installation.... --212.159.69.172 18:03, 2 July 2006 (UTC)
StarTeam text is overboard: "A robust platform... promotes team communication and collaboration..." I don't know enough about it to supply a better description. Paul F. Williams 20:12, 6 June 2007 (UTC)
Likewise - Clearcase described as "Market leading" —Preceding unsigned comment added by 147.200.199.37 (talk) 00:22, 25 June 2008 (UTC)
Internal links
[edit]If someone had a mind to it, it would be nice to replace all the external links with internal (possibly red) links followed by the internal link. e.g., replace:
- TLIB - ...
with
Maybe there's a tool to make this easier. Basically, all these tools warrant actual articles about them, rather than just a link to the corporate website. Stevage 05:23, 3 November 2006 (UTC)
MediaWiki
[edit]I've added MediaWiki to the list, since technically it meets the criteria for being revision control software. If that was too bold, then let me know and I'll revert or change it. --Bill Clark 12:34, 3 November 2006 (UTC)
- Maybe it warrants inclusion in a separate category. MediaWiki, to my mind, *is* not revision control software, but it *has* it built in. MediaWiki is not well suited at all to storing revisions of a project written in C, for instance. It's really only good at storing revisions of wiki pages - just like lots of software can store revisions of its own data files. Stevage 05:12, 4 November 2006 (UTC)
Linkfarm
[edit]This list is little more a linkfarm, in violation of WP:EL - Wikipedia is not a directory of software. I am going to remove anything that is not considered notable. By precedent, the best criterion for assessing this is whether the software has an article on Wikipedia. The appropriate way to add software not in the list, assuming it satisfies WP:NOTE and/or WP:SOFTWARE, is to create an article about it. That way, the notability can be established and/or discussed via the usual channels. CiaranG 21:20, 15 January 2007 (UTC)
Client/Server
[edit]I think there's more than just 2 categories for this. For example, Visual SourceSafe is a filesystem based system, not traditional client/server. Client/server would indicate there is some piece of software accepting requests on a server. VSS just reads and writes to a file on the filesystem, and uses it's own form of file locking. There have to be others that do this as well (basically, similar to the way RCS/SCCS operated). I'm not sure what the best way to classify that would be. Maybe this would work better as a comparison chart. TheMadGerman 20:50, 20 September 2007 (UTC)
.SCC compliant, what is that?
[edit]Some revision control systems are marked as SCC compliant: RCS, SCCS, Clearcase, Telelogic Synergy.
It is not explained in the article what ".scc compliant" means. Nor is it evident from the linked page http://filext.com/file-extension/scc. That page doesn't use the word "compliant". The article should either remove the use of ".scc compliant", explain its meaning, or link to a page that does explain it. --HelgeStenstrom 12:00, 5 November 2007 (UTC)
RCS performance
[edit]The claim (made by the RCS people) RCS is faster than SCCS is definitely wrong. Even when retrieving the most recent version, SCCS is aprox. twice as fas than RCS. When retrieving the oldest revision and there are many revisions, RCS is aprox. 4x slower than SCCS. If you don't believe this, run your own tests. --Schily (talk) 13:12, 20 June 2011 (UTC)
- The original one also, or only that of your revival? --129.187.150.74 (talk) 22:01, 20 June 2011 (UTC)
- RCS is faster than SCCS for retrieving the most recent version. Going back more revisions requires reconstructing the older revisions by applying editing scripts (contained in the archive). Successively retrieving older revisions steadily increases the cost. SCCS stores all of the information interleaved in the archive, so that retrieving any given archive is about the same cost. It depends on which you're attempting to prove. fwiw, most people are interested mainly in comparing against the most recent revision. (This is for the trunk - RCS branches have problems not found in SCCS). TEDickey (talk) 22:49, 20 June 2011 (UTC)
- SCCS takes the same time to retrieve the latest and to retrieve the oldest version. RCS takes twice as much time than SCCS to retrieve the latest version and four times as much time than SCCS to retrieve the oldest version. The claims from the RCS people (RCS is supposed to be faster than SCCS) never have been verified, but my numbers agree with the numbers from Larry McVoy with his BitKeeper SCCS implementation. BTW: my version is the original software. --Schily (talk) 23:01, 20 June 2011 (UTC)
- That's still not addressing the topic at hand, which needs a WP:RS. TEDickey (talk) 23:33, 20 June 2011 (UTC)
- Well, it is easy to verify that SCCS is faster than RCS. But even without a test, it is easy to understand why SCCS cannot be slower: SCCS does not store deltas but the weave format which allows to access any version at the same cost. --Schily (talk) 23:44, 20 June 2011 (UTC)
- It's trivial to demonstrate the converse. Start with an archive containing a thousand revisions. If all I care about is comparing against the last revision, SCCS will always be slower than RCS, if the content of the current revision is small enough. (I have some files with more revisions than that). Whether they are actually faster/slower, depends on the data (number and size of revisions, as well as the number of chunks that change in each). However, all of this is moot - WP:RS is where your attention should lie TEDickey (talk) 23:56, 20 June 2011 (UTC)
- So you like to tell us that you did never run any own comparison? RCS may have been faster in than SCCS in 1982 with thousands of changes and on a computer with only 1 MB of RAM and a with filesystem that is slow with reading files > 64 kB, but nearly 30 years passed since then. BTW: I did run mý main tests with 10000 deltas but there is a clear tendency in the tests that RCS is slower under any circumstances. But I am open to new experiences, so feel free to present us a repeatable test that proves your claim. --Schily (talk) 08:56, 21 June 2011 (UTC)
- Your comment about a test with 10000 deltas is misleading. For RCS to read the tip revision, it reads (as does SCCS) a summary of the revision list, followed by the content of the tip revision. SCCS does additional work at this point, reading through an extra 20000 lines (one each for start- and end-deltas). The statement made regarding RCS (which is what you're disputing) is that access to the tip version is faster. Conflating it with discussion of older revisions is nonconstructive. I'd want to see a benchmark that I could run myself before discussing the latter, even though that appears in at least one FAQ TEDickey (talk) 09:49, 21 June 2011 (UTC)
- I've added a reliable source for the original statement. There is of course Tichy's paper here which you have alluded to. If you want to continue the discussion in lieu of providing a reliable source, you're welcome to do so on this page. Disparaging remarks will of course detract from the discussion. TEDickey (talk) 09:54, 21 June 2011 (UTC)
- I am sorry to see that you again did not prove that RCS is faster than SCCS but just give quotes to people who claim that RCS is faster without giving any prove.
- Please stop your edit war on the article as long as you cannot prove your claims. RCS is not faster than SCCS under all conditions I test.
I did run more tests that all give similar results. This simple test:
#!/bin/sh i=0 date > foo ci -mnone foo < /dev/null while true; do i=`expr $i + 1` if [ $i -eq 10000 ]; then break fi co -l foo date >> foo ci -mnone foo < /dev/null done
takes 27 minutes of wall clock time, 850 seconds of user CPU time and 325 seconds of System CPU time and creates a foo,v with 1605635 bytes.
After you are ready, "co foo" takes 86ms wall clock time and 70ms uf user CPU
"co -r1.1 foo" takes 110ms of wall clock time and 100ms of user CPU
This test with SCCS:
#!/bin/sh i=0 SCCS=/opt/schily/ccs/bin mkdir -p SCCS date > foo $SCCS/admin -ifoo -fy SCCS/s.foo rm foo while true; do i=`expr $i + 1` if [ $i -eq 10000 ]; then break fi $SCCS/get -e SCCS/s.foo date >> foo $SCCS/delta -ynone SCCS/s.foo done
takes 14 minutes of wall clock time, 440 seconds of user CPU and 49 seconds of system CPU and creates a SCCS/s.foo with 1314546 bytes
After you are ready, a /opt/schily/ccs/bin/get SCCS/s.foo takes 40ms of wall clock time and 30ms of user CPU time
/opt/schily/ccs/bin/get -r1.1 SCCS/s.foo takes 36ms of wall clock time and 30ms of user CPU time.
BTW: this creates reverse deltas that are easy to trace for RCS but since recent RCS versions have been highly optimized, you get similar results with random edits (I did run related tests).
Conclusion: SCCS is aprox. 2x faster than RCS. Do you have more than unproven claims that would allow me to repeat something I can believe because it is tangible? --Schily (talk) 12:22, 21 June 2011 (UTC)
- I get different results, using your script. Testing on Solaris 10 (closest at hand), the SCCS script does not run without modification due to a writable file (fixed using chmod). I further modified both scripts to move the "10000" where it could be overridden via an environment variable, and redirected the output (and errors) to a file. The RCS messages (which of course can be quieted), were 2063444 characters, while SCCS provided 984256. However, the real time reported was 20m5.58s and 17m4.59s (RCS and SCCS respectively), with comparable results for user- and system time. It's likely that you're misled by your script, if you're supposing that it supports "aprox. 2x faster".
There are of course further factors that might make the result go either way (since you're not actually measuring the feature under discussion, but instead are measuring the gross program behavior, which includes several factors). The "10000" by the way, is a waste, since similar results can be shown for smaller repetitions. TEDickey (talk) 22:39, 21 June 2011 (UTC)
- Writable file??? if you have a problem, you should name it, I have no idea what you could mean with "fixed using chmod". The script works the way it was posted, I did however redirect the error messages from RCS. As you did only provide numbers that confirm my statement, could you explain why you asume that I misinterpret my results? I am open to new tests, but it is obvious that RCS is not faster because of a better concept. On systems like AIX, SCCS is not faster than RCS, but this is a result of the slow filesystem on AIX and the higher number of temporary files with SCCS and the slow filesystem on AIX can be verified by checking star -x -no-fsync speed.
- If we look at the main claim from Tichy: "unpacking is more efficient with RCS because if the better history file design"... the tests show that RCS needs more user CPU time when retrieving the last revision and current RCS versions use mmap() to access the history file. And BTW: the 10000 is not a waste as e.g. GNU CSSC uses an algorithm to unpack the weave data that scales with ndelta**2. I did run my tests with Solaris 11 on a 6 year old Opteron system. --Schily (talk) 23:42, 21 June 2011 (UTC)
- Regarding "writable file" - the program refused to overwrite the writable "foo". I tested with both Solaris SCCS and CSSC (same result). And as I pointed out, my numbers don't support your statement TEDickey (talk) 23:55, 21 June 2011 (UTC)
- This is why there is a "rm foo" in the script..... and your numbers support my numbers as your test also shows that RCS is slower than SCCS. As I don't know whether you used a recent SCCS or vanilla Sun SCCS, you may have testetd with Sun SCCS that calls write(2) with a transfer count of 1016 bytes (which of course slows down SCCS). Sun SCCS also uses a silly algorithm to check for binary content that is slow and that has been replaced in the recent version of SCCS. --Schily (talk) 07:53, 22 June 2011 (UTC)
- None of your modifications to your argument improve your case measurably. What I walk away with is the impression of strong bias, which is inappropriate for benchmarking, more appropriate to marketing (or a hacker) than an engineer. In Wikipedia, this is called WP:OR. Bye TEDickey (talk) 08:10, 22 June 2011 (UTC)
- OK, I see that you are biased and either not willing or not able to understand that the main claim from Tichy is void. You however confirmed that you don't have numbers to confirm his claim. Given the fact that SCCS is twice as fast than RCS on Solaris verifies that the inteleaved deltas (called weave) as used in SCCS are a good choice. A scientific talk about this topic would need numbers and arguments that I did not see from you. But thank you for confirming by naming WP:OR that the Tichy paper cannnot be used as a base to verify the claim that RCS is faster (it not even contains numbers anyway). So it is obvious that we need to revert your latest edit in the main article. --Schily (talk) 08:40, 22 June 2011 (UTC)
- hmm - no amount of repetition will prevent you from pretending that I'm agreeing with you. Perhaps you can submit your original research to a reputable journal, and get it published. Your comments here are of course, an unreliable source of information, and it is noted that no facts have been established TEDickey (talk) 11:03, 22 June 2011 (UTC)
- In any way, the paper from Tichy cannot be called scientific with respect to the performance claims as it does not contain provable facts but just claims that have been disproven by my test results. If you like to convince me and believe that you found facts that disprove my results, you would need to give more facts, and if you like to be scientific here I would expect to see a related theory from you. As you however confirmed that your tests also resulted in RCS being faster than SCCS, I need to asume that you agree with me. --Schily (talk) 11:46, 22 June 2011 (UTC)
- You might want to contact Professor Tichy at the University of Karlsruhe / KIT: http://www.ipd.uka.de/Tichy/index.php - I see little reason to not trust his research, he's an ACM distinguished researcher, and RCS is also very well known. Maybe you just need to read another paper that has more details. Also try on other operating systems. Preloading of the history file by the operating system might bias your data, and your benchmark probably just analyzes how well the software and your operating system cooperate. And for Wikipedia, a published article by a distinguished computer science professor does indeed qualify as reliable source. Your own benchmarks here do not: WP:OR --87.174.110.113 (talk) 11:25, 24 June 2011 (UTC)
- I don't care who publishes wrong claims. In our case, it was Mr. Tichy. As mentioned before, Tichy did never give any method to repeat a test that could verify his claims and he did not even ever give numbers, so his claims cannot be called scientific. Tichy's claims for that reason are obviously WP:OR and you either need to find an independent source that verifies your claim or we need to remove the unproven claim that RCS is supposed to be faster than SCCS. BTW: It may be that RCS has been faster than SCCS in 1982 when on a machine with the old AT&T-V7 filesystem and with less than 4 MB of RAM. Todays machines behave different than 30 years ago and iff RCS really has been faster than SCCS in 1982, this was a result from other reasons than the ones claimed by Tichy. The most important reason, why RCS may not be slower than SCCS on some platforms is that it needs less rename operations on intermediate files and this a fact that is missing from Tichy's paper.... --Schily (talk) 11:55, 24 June 2011 (UTC)
- Additional hint: I meanwhile found an original paper from Tichy from 1982 that verifies that he used a 4 MB machine running a UNIX-V7 file system. As Tichy did only check 10 revisions and his results for RCS have only been slightly faster, it is obvious that he did just meter the UNIX V7 file system performance and the checksum performance in SCCS (RCS has no checksums) but not RCS vs SCCS performance. Today, such a test has absolutely no meaning anymore, as we use modern fast filesystems and computers that have no problem to calculate checksums quickly. --Schily (talk) 12:54, 24 June 2011 (UTC)
- I don't care who publishes wrong claims. In our case, it was Mr. Tichy. As mentioned before, Tichy did never give any method to repeat a test that could verify his claims and he did not even ever give numbers, so his claims cannot be called scientific. Tichy's claims for that reason are obviously WP:OR and you either need to find an independent source that verifies your claim or we need to remove the unproven claim that RCS is supposed to be faster than SCCS. BTW: It may be that RCS has been faster than SCCS in 1982 when on a machine with the old AT&T-V7 filesystem and with less than 4 MB of RAM. Todays machines behave different than 30 years ago and iff RCS really has been faster than SCCS in 1982, this was a result from other reasons than the ones claimed by Tichy. The most important reason, why RCS may not be slower than SCCS on some platforms is that it needs less rename operations on intermediate files and this a fact that is missing from Tichy's paper.... --Schily (talk) 11:55, 24 June 2011 (UTC)
- If your "benchmark" were related to the statement in discussion, that might be relevant (without the inferences which underlie your comment). Not the case of course. TEDickey (talk) 20:49, 24 June 2011 (UTC)
- If you don't understand the relation between the benchmark and the wrong claim you introduced into the article, you may be the wrong person to discuss this topic. Why dou you continue to reinsert claims that have been proven to be wrong? --Schily (talk) 21:48, 24 June 2011 (UTC)
- Hmm. We've been here before (keep the discussion civil rather than accusing people who do not accept your claims as being incompetant) TEDickey (talk) 22:12, 24 June 2011 (UTC)
- While you were working on your edit war and reverted the article to it's incorrect state, you ignored the fact (see history comments of the main article) that there is a second independent source (Larry McVoy) who also disproves the claims from Tichy. Why do you ignore two independent research results in favor of a claim from Tichy that even contains enough information to prove that Tichy's conclusions are the result of a missinterpretation? --Schily (talk) 10:30, 25 June 2011 (UTC)
- My definition of "independent" must be badly wrong. Or yours! Actually, both Larry McVoy and you have one thing in common: you have a strong Sun/Solaris history. One of the reasons Larry McVoy gives for SCCS instead of RCS is: "I learned SCCS at Sun". In fact, Larry McVoy acknowledged that accessing the trunk version is faster in RCS, but he needed fast branch access for BitKeeper. Btw, there are also pointers on how your benchmark is flawed: It does in fact favor SCCS "weave" format by the way you modify the file across revisions, I beleive, which makes the weave representation more favorable than the diff delta representation used by RCS? And actually, I believe you were very well aware of your benchmark being biased towards SCCS weave format. --87.174.37.97 (talk) 15:20, 25 June 2011 (UTC)
- I'm not going to do my own benchmark (that would be WP:OR, and thus irrelevant. Tichy by not being part of Wikipedia btw. cannot be WP:NOR). But I figure that if you'd replace the file contents instead of appending that would make SCCS look much worse. From what I read, SCCS is O(n) with n the number of unique lines across revisions. RCS HEAD access supposedly is O(m) with m being the HEAD file size. Your benchmark used m==n, whereas in reality, n>>m is to be expected. I am convinced you deliberately used this flawed benchmark, and we therefore must not trust your benchmark results. I figure it is undebated that merges and branches in RCS are awful and slow. Btw, isn't SCCS single-file only also? If so, we should put this into the section description. --87.174.37.97 (talk) 15:46, 25 June 2011 (UTC)
- While you were working on your edit war and reverted the article to it's incorrect state, you ignored the fact (see history comments of the main article) that there is a second independent source (Larry McVoy) who also disproves the claims from Tichy. Why do you ignore two independent research results in favor of a claim from Tichy that even contains enough information to prove that Tichy's conclusions are the result of a missinterpretation? --Schily (talk) 10:30, 25 June 2011 (UTC)
- Hmm. We've been here before (keep the discussion civil rather than accusing people who do not accept your claims as being incompetant) TEDickey (talk) 22:12, 24 June 2011 (UTC)
- If you don't understand the relation between the benchmark and the wrong claim you introduced into the article, you may be the wrong person to discuss this topic. Why dou you continue to reinsert claims that have been proven to be wrong? --Schily (talk) 21:48, 24 June 2011 (UTC)
- If your "benchmark" were related to the statement in discussion, that might be relevant (without the inferences which underlie your comment). Not the case of course. TEDickey (talk) 20:49, 24 June 2011 (UTC)
- Since Schily now claims that Larry MacVoy also said that SCCS is faster than RCS, let me quote him with some empahsis and comments added:
- The myth about SCCS getting slower is nonsense and in fact, the opposite is true for the sort of revision history that is found in BitKeeper trees [comment: i.e. not in general]. RCS is optimized for getting the most recent version on the trunk [comment: this is what the article says: "faster access to the trunk tip"]. All other versions are slower and branch versions in RCS get really slow. [comment: the article says "at the cost of slow branch tip access"] SCCS time to get any version is constant. [comment: constant apparently means: independent of the revision number, whereas RCS needs to apply n deltas to go n versions back]
- So in general, I'd say we can actually add MacVoy as another sources that supports the claim that RCS is faster for accessing the branch tip version. It's not faster for BitKeeper-internal use. --87.174.37.97 (talk) 15:54, 25 June 2011 (UTC)
- One obvious flaw in the benchmark is that it assumes that check-in (and the associated work of constructing a diff) are just as frequent as retrieval of the tip-revision (which the disputed statement singled out). I suppose it's possible to construct a workflow that used a write-only archive (essentially matching the benchmark), but expecting other editors to accept it as unbiased is unrealistic. TEDickey (talk) 16:07, 25 June 2011 (UTC)
- It seems that I need to admonish you again to come to a fact based scientific discussion.
- RCS is always slower than SCCS. Even if you retrieve the latest version, RCS co is typically 1.5x .. 3x slower than SCCS get and when you retrieve older versions, RCS (even release 5.7) slows down by an additional factor of 2 while SCCS retrieves all versions at the same speed. So RSC is up to 6x slower than SCCS.
- This statement is true for all operating systems with more than 4 MB of RAM and with a filesystem that is better than the UNIX-V7 filesystem. I tested on many operating systems...
- The original claim from Walter Tichy has been made from simple tests on a VAX with 4 MB of RAM that used a UNIX-V7 filesystem that is really slow with retrieving files > 32kB. As the original test from Walter Tichy was a test that only included up to 10 revisions in a history file, the results have been missinterpreted by him as the small differences he detected are a result from the missing cheksums in RCS and from the fact that the UNIX-V7 filesystem slows down when reading larger files. Modern filesystems however implement a very efficient read ahead in case that a linear reading access is detected. This results in typically no additional costs to read the whole file compare to reading only 2/3 (a typical value for RCS).
- As his observed "performance win" from RCS was much less than the factor of two, it can be seen as a very dubious result. With machines having more RAM and using UFS (a much faster filesystem) in the mid 1980s, a vanilla SCCS was expected to be always faster than RCS past 1982.
- In the late 1980s, UNIX implementations did add support for automated DST switching in the libc functions that handle local time. This support has been implemented in a very inefficient way and as SCCS uses local time in the history file, this caused SCCS to slow down around 1990.
- Solaris revised the local time support functions during the past 20 years and thus SCCS on Solaris was much faster than on other platforms since a while. The most recent version of SCCS implements a workaround for slow local time support functions and dramatically improves SCCS performance. On SunOS-4.1, this optimization did speed up SCCS by a factor of 10.
- Note that all performance optimizations that have been recently introduced in SCCS affect only code that has been introduced past 1986. So it would have been sufficient to compare RCS and SCCS on a decent file system in 1983 in order to verify that the claims from Tichy are no more than a myth.
- Also note that the performance tests I did run are in favor of RCS, as typical filesystems on many OS (AIX, Linux, ...) implement slow directory operations, a SCCS delta gets a performance penalty on those OS because SCCS delta uses more temporary files than RCS ci. Thus if you compare overall performance, SCCS may only be 20% faster than RCS while SCCS get offers a bigger performance win. --Schily (talk) 09:47, 6 July 2011 (UTC)
- Reading through your comments, two issues are apparent: (a) you have only repeated your previous assertions without providing a WP:RS, and (b) you are not responding to any of the points which have been made TEDickey (talk) 10:03, 6 July 2011 (UTC)
- I am sorry to see that you still repeat your unsourced claims. Once you give statements that are based on repeatable facts, I am happy to respond to you. For now, I cannot see any valid and/or repeatable claim in your statements and thus have no idea what to respond to. You neither have a theory nor a confirmation for the claim that RCS is faster as we need to call the paper from Tichy unrepeatable and self claimed. My statements are however all repeatable and based on validated theories as I was able to improve the performance on many OS platforms from applying the theories. --Schily (talk) 13:21, 6 July 2011 (UTC)
- Reading through your comments, two issues are apparent: (a) you have only repeated your previous assertions without providing a WP:RS, and (b) you are not responding to any of the points which have been made TEDickey (talk) 10:03, 6 July 2011 (UTC)
Is the above information of RCS vs. SCCS really needed and should it be in the talk page? It's 2013, FFS. RCS vs SCCS is pretty irrelevant anymore, on a level about whether castor oil is a good additive for that 1903 Ford. :-) 78.141.139.10 (talk) 15:45, 19 March 2013 (UTC)
- I don't know what you understand by FFS. RCS may have been relevant because of usage. RCS however never was relevant because of the ideas behind it. Note that RCS is much slower than SCCS and gives less features than SCCS.
- SCCS of course still has relevance because all recent source code control systems that offer distributed usage have been derived from the ideas behind BitKeeper SCCS which is based on a SCCS clone and as the first distributed systems, e.g. NSE (Sun's Network Software Environment from 1986) and Sun's TeamWare from 1990 are all based on SCCS (they are in fact SCCS front ends),
- The problem in the main article still exists. It claims that RCS is faster than SCCS and tries to verify this with the Usenet FAQ that contains no more than an unproven and unprovable claim. So this claim in the main article can only be seen as "original research" that is not allowed in Wikipedia. Even Mr. Tichy did only claim RCS to be 1.2x faster than SCCS when using less than 10 deltas. He did not publish the exact constraints, so his claims cannot be proven. His results can be explained by the missing integrity check in RCS, but testing less than 10 deltas is not related to reality. The fact that SCCS is much faster than RCS can be proven (the scripts to repeat the test have been published). If you use the Solaris SCCS binaries, RCS is (in the best case for RCS) 2.5x slower than SCCS. If you compile yourself a recent SCCS source version (e.g. SCCS version 5.06) and comopare this with RCS, RCS (in the best case for RCS) is 6x slower than SCCS. If the files are larger than 126kB and you use a recent RCS, add another factor of 2 to the time spend in RCS. This is of course relevant, as the false claims about RCS performance misleaded software developers for aprox. 20 years and caused them to use an inferior system. Schily (talk) 09:39, 8 May 2014 (UTC)
List of SCM tools
[edit]The list of SCM tool at List_of_build_automation_software should be scratched and merged into here or something. 78.141.139.10 (talk) 15:45, 19 March 2013 (UTC)
- Agree. Stevebroshar (talk) 15:45, 30 May 2024 (UTC)
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Distributed and ClearCase
[edit]ClearCase should be under distributed. There are a gazillion companies spread over the world who use ClearCase distributed. A developer has his own branch and only when he checks in it becomes part of the main branch, which on its own can again be part of another branch. Furthermore, the VOBS are distributed, so that any department can work locally while on the background the VOB storages sync between locations. Etc... This means no reliability on one main server such as Github or something to check in or check out to. You can work locally, on top of that locally in your department. — Preceding unsigned comment added by 91.90.44.24 (talk) 13:33, 30 July 2020 (UTC)
Organizing by attribute
[edit]Organizing anything by category is foolhardy. What eventually happens is that the categories from one point in time don't apply at a later point in time. Often lines get blurred between categories. Better to tag items with attributes. Today, one dimension is: local, client-server, distributed. Another dimension is: proprietary vs open-source. I think there should be one, flat list and each item tagged with the value for both dimensions.
Maybe a second list of obsolete guys. That hard separation seems maintainable and useful. Stevebroshar (talk) 15:43, 30 May 2024 (UTC)
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