Thursday November 03, 2005 Random ramblings
Thursday November 03, 2005 Been playing with Git recently. It's pretty good. The documentation isn't bad, and despite appearing a bit daunting to use initially actually is quite straight-forward and easy to use if you follow the tutorial (unlike, e.g., the initially promising and attractive GNU Arch, which you discover can be hard to use at times and very "quirky": bad UI and its author decided Arch should enforce his preferred way to categorise and name branches of projects).
The plan for OpenSolaris apparently is to use SVN initially for a RO, centralised, public SCM of the ON code, I gather. What to use in order to open up OpenSolaris to full distributed development is still an open question (SVNK? Teamware?). SVN (and hence SVNK) I have reservations about, I find the Apache APR which it is coded in to be, well, jarring - bit like when you first log in to a VMS system and try to figure out how to 'ls'. Also, it uses a Berkely DB backend as storage, which has not been unknown to cause problems. It also had pretty severe performance problems last I checked (a long time ago). Finally, the preferred network access daemon is Apache, and the configuration can be complicated and error-prone (last I checked the standalone 'svnserve' daemon was a second-class citizen and missing stuff like authentication (cause running it over ssh is good enough for everyone)).
Teamware is really nice (the original distributed SCM?), but shows its age in places, even if you use the excellent 'wx' wrapper (e.g. try pulling per-putback changesets from Teamware - not easy, particularly when the SCCS files used for "backend storage" use localtime for timestamps).
Git though, from some initial use, would fit reasonably well with the workflow currently in use with Teamware. It's essentially a content-addressable filesystem. It features:
- Log messages for both commits and merges. Hence if you want a per-file log message, commit the changesets for the files concerned individually (or whatever granularity is desired). You still then will specify a log message for the 'putback' to the upstream gate to cover the whole putback
- Push and/or pull merging between gates
- Space efficient sharing of repository files between different local branches, even between different local repositories on the same local filesystem.
- Hence quite good (ie fast) local branch/clone support.
- Transport agnostic. Can work over any "dumb" file sharing protocol, rsync, NFS, can work over remote shell interfaces (ssh) or with a native protocol.
- All the usual hooks
- Very granular, tool-per-task orientated. Very suited to layering a more cohesive SCM toolset on top of it (see, e.g. 'cogito'. One could imagine also 'wx' ported to work with git instead of Teamware).
- Surprisingly easy to work with. If you do get confused, there's always "git reset" to undo things (either back to 'master', or to an arbitrary changeset).
Initially written by Linus Torvalds of course, but then he'd been using Larry McVoy's Bitkeeper for many a year, and before Larry did Bitkeeper he had been working on Teamware at Sun.
There's also Mercurial / Hg, which is what the Xen project switched to after bitkeeper. Also a 'pure' distributed SCM. But havn't checked that out.
( Nov 03 2005, 08:35:56 AM GMT ) Permalink Comments [2]
Trackback URL: http://blogs.sun.com/paulj/entry/git_scm
Post a Comment:
Posted by Ken Lareau on November 03, 2005 at 07:41 PM GMT #
Hi Ken,
In fairness, I did say it's been a long time since I "checked out" SVN. However, on the other hand, from your response it's fair to say that several of my points remain valid - hardly FUD. Further, this post wasn't meant to be a review of SVN, fair or not (e.g. I'm aware svnserve performs quite well, much better than the Apache access method. Hence, indirectly, my comment on svnserve and authentication), but rather a comment on Git.
Yes, SVN is better than CVS. But, for me it's not better enough. I also admin the SCM for a Free Software project, Quagga, which has been creaking along using CVS, which I'd dearly love to replace with something better.
Posted by Paul Jakma on November 04, 2005 at 11:29 AM GMT #