Reading from Tape

Data is read from tape most commonly via a command named jget.  The requirements for using this tool
are:

1. a valid scientific computing
   certificate as described in "Getting
   Started",
   
2. access to /site/bin/jget on a
   supported machine.

Files may also be read from
tape via other special-purpose tools documented elsewhere. 
Regardless of the the way that read requests are generated, the
ultimate process that jasmine uses to service those requests is as
follows:

1. For each source file in the
   stub filesystem, the request will fail if any of the following
   conditions pertain:
   

• the file does not exist.

• destination file already exists,
  
• another request already
  exists to write the same destination (either same location on network filesystem, or same local path on same host machine),
• the user does not have
  permission to write the destination file.

• Pending - the
  job is waiting to be
  processed
• Staging - the tape is being prepared for reading the file
  
• Staged - the tape is ready to read the file
  
• Running -
  the file is being read from tape and written to its destination
  
• Done - the file was
  successfully read from tape and written to its destination
  
• Cancelled - the job was
  cancelled
• Failed - an error
  prevented the file from going from tape to its detination
  

If a
non-fatal error occurs at any point in the processing of a file, its
state will automatically be reset for a future retry.  The jget client will display each job's state as it is
updated.