Coda is an Advanced NetworkFileSystem developed as a research project by the team which wrote AFS. Coda extends the FileSystem for DisconnectedOperation.

Some of AFS' developers noticed that caching lets it work quite well for a while in the face of loss of the connection except for issues when writes occur. Coda was to allow for scenarios like allowing a laptop with a WLAN connection wandering in and out of range to seamlessly synchronize all files (and notify the user of conflicts). The project was quite a success.

Coda is supported in Kernel 2.6.7 but no longer in active development. It seems to still be maintained, however, as it is not completely dead -- the last release as of July 2004 was v6.0.6 in April. Currently it seems to be the only option for a FileSystem with support for DisconnectedOperation until OpenAFS supports this as well.

Update April 2005: Coda remains active, though this is only clear from looking at the mail list archives. Documentation at the web site is out of date, so the mail lists are the current authoritative source of documentation. This may be about to change as several new users have expressed an interest in bringing the documentation up to date.

A former developer of Coda started Intermezzo as a simpler implementation.