The AndrewFileSystem:

• was developed as part of the AndrewProject
• is a NetworkFileSystem
• uses full ACLs rather than traditional Unix permissions - see AFSACLs
• supports replication of the filebase across multiple servers for Reliability and Availability
• uses Kerberos for Authentication (Kerberos5 prefered, though Kerberos 4 is native to OpenAFS)
• uses "tokens" tied to your UID to your PAG, which are Kerberos 4 tickets stuffed into the kernel
• can cache files locally for fast access even to files only available to you over a slow link
• was originally called "Vice" (the Andrew Toolkit was known as 'Virtue')
• no longer copies the entire file when it's opened for writing, which is slow for large files - though Coda still has to in order to support disconnected operation

Some of its authors noticed that AFS worked quite well for a while when you unplugged the network, due to caching, but has issues when writes occur. A research project called Coda was launched to allow fully disconnected operation: a laptop with a WLAN connection wandering in and out of range will seamlessly synchronize all files (and notify the user of conflicts). The project was quite a success.

Then its team decided that they could do better, so they sat down and started working on Intermezzo. This project is based on the same principles as Coda, along with the idea that it should be as fast as using a local filesystem, and should do everything over well established protocols (such as HTTP). I doesn't seem to be anywhere near production quality yet, though. Coda is unmaintained and pretty much unused nowadays.

AFS however continues to thrive, offering gigantic scaling capacities.

See also:

• OpenAfsUserCrashCourse
• AFSNotes
• Setting up OpenAFS under Debian