Shared File Directory : Hugh's Lab

File system : pull

A directory containing files that hold shared state

Absolute Consistency ! : Only one host can write data to the same file at a time.

Locate the file containing information and read/write the file data (file:user, object information)

Read and the reopen in write only mode

Maintain "lock" information for each file, and only one writer may hold that lock at a time

Ex. : NFS, AFS

Pros.

• Simplest to program

• Highest consistency

Cons.

• Slow data update and access

• Does not support many users
  Constant need to open, update, close remote file

eScience