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"Diagnosing SVN" is one of the most widely linked. I think there've been a few others as well, but I couldn't locate them immediately.

I wonder if they'll use arch as their RCS, since it is made specifically for distributed branches developpement.

• Arch is what makes Xouvert possible. Arch is Tom Lord's advanced changeset management system, a superset of mere "revision control systems" like CVS and Subversion. Arch will let us make radical changes to the directory layout of Xouvert, yet still be able to easily track and apply the changes in the original Xfree86 tree.

• The clean design of arch makes it trivial for anyone who downloads our source code to create their own local "branch" for development, keep it under revision control, then have their modifications merged, with complete history, back upstream at some point in the future. This is next to impossible to do with CVS.

There are other projects that have started using Arch; for example, I noticed Y, mentioned in another comment, also uses it (just a coincidence, or a case of Y influencing Xouvert?).

Any slashdotters used it? I'm doing some testing with Arch and if I end up deciding I really like it, I'll try persuading my colleagues that we should adopt it as our company's source code management system. Mmm... atomic commits.

because of what it says on the website:

Incomplete Implementations
At the moment, these implementations are very rough, and only useful to look at if you're a developer. http://arch.fifthvision.net/bin/view

While it sounds interesting, if you're choosing a version control software, "stable" and "well tested" are at the top of your list.

BitKeeper is in use because it's better than the available free tools.

Seen Arch?

Arch has changeset support as well, *and* the same distributed repository support as BitKeeper, *and* a dumb server model (keep your repository on any unmodified WebDAV/SFTP/FTP/whatever server), *and* far better platform support, *and* is available under a Free license.

Subversion also has atomic checkins, but it suffers from severe reliability and design issues (read the arch-users list archives for an analysis of the latter).

As for McVoy, my first interaction with him was through MontaVista Software, my employer at the time. We were using BitKeeper for developing Free software, and took advantage of the no-cost license (letting our changelogs be published to BitMover's site). McVoy changed the license such that we, specifically, would be out of compliance -- and terms were such that we were obligated to upgrade to any newer beta and accept its license or cease using BitKeeper. Being much smaller than presently, MVista had to fold and go back to CVS -- and fun that was *not*.

Even forgiving its author's antics, I'm still not fond of arch. Back at the time, its repositories tended to corrupt at the drop of a hat, and grow far larger than need be (particularly compared to the alternative I'll be introducing shortly).

TLA, the C version of Arch (a version control system by Tom Lord), has much more promise. It has the same distributed repository paradigm as BitKeeper, but is under a Free license. It doesn't have the graphical merge tools, but is written such that adding one would be very easy -- and it *does* have some nifty extra features such as the star merge algorithm (which prevents spurious conflicts in the case of multiple branches which are merged back and forth -- a common situation in open source development).

Ever wanted to make your own branch of a project but didn't have write access to the repository? Been annoyed by CVS's lack of support for versioning things like directory moves, file renames and the like? If files are given internal tags in arch, the VCS will even detect file renames *automatically*, without being told at all!

One final, strong, item in favor of arch: The repository format is simple and well-documented, and by its design unlikely to corrupt in ways that can't be fixed by hand. None of the crud like CVS's rewriting ,v files (and thus permitting opportunities for a power cycle to kill all of a file's history).

So, to sum up: Arch is nifty. Arch is good. Arch is written by someone who is much less of a $@%#% rat bastard than Larry McVoy. You should try arch.

Oh, you want to know where? See the arch wiki or Tom Lord's home page.

Have fun!

McVoy once talked on lkml about alternatives and uttered sth. like "if any other system can ever come close in features then it will be arch". Afaik an upload of all kernel versions into an arch repository is under way already for 2-3 weeks as a test, so maybe with some heavy code-reviewing-and-feature-hacking a replacement for BK can be there in a month or so. Arch can be found here: arch</ a>

Found it!

http://www.fifthvision.net/open/bin/view/Arch

What's really new about arch is that it makes version control decentralized, rather than merely distributed, as CVS and Subversion do. In arch, any branch, any developer's private work area can be regarded as a repository of its own, with a global name space for developers, repositories, and branches, to manage this.

With CVS and Subversion, the repository is still a centralized entity. Compared to arch, these systems are still at a similar conceptual level, while arch adds something that is really new.

Of course, no discussion of CVS's strengths and weaknesses vs. Subversion would be complete without mention of the third contender, arch. Link 1, Link 2.