Every so often, someone says that git is badbecause it lets you rewrite history (usually they have other reasonstoo). This almost invariably irritates me because it is so completelywrong at a deep level.

Git has no support for 'rewriting history' in any meaningful sense. Infact, git's design means that by its very nature you cannot rewritehistory. Since a commit is identified by the hash of its contents,you cannot change a commit once it is made. Since commits identifytheir parents

Here are some quick (or at least short) reactions to all of the newshows of spring 2009 that I've watched some of, written down for variousfuzzy reasons. I am not going to try to summarize or review these, justgive some brief comments.

Rather than agonize over quality ratings, I've decided to rate showsbased purely on how eagerly I'm looking forward to the next episode,from +3 ('want more right now') to -3 (

Suppose that you have a ZFS pool that you have filled utterly up to thebrim, completely full, and that it has a snapshot. Of course, now youneed to delete some files in a filesystem to clean up space, so:

$ rm oldfile
rm: cannot remove `oldfile': No space left on device

(Here oldfile is a file that is old enough to be in the snapshot.)

The ultimate cause of this is a general problem with 'copy on write'filesystems such as ZFS.