File system failure

These events can be symptoms of file system failure:

0F4 abend
EMVSPFSFILE return code
EMVSPFSPERM return code
A file becomes unrecognizable or cannot be opened

After a failure of a file system, the operator:

Restores the file system with the file system from the previous level.
Asks a superuser to logically mount the restored file system with a TSO/E MOUNT command.
Notifies all shell users that when they invoke the shell they will mount an earlier file system, telling them the mount point. (Use the wall command to broadcast a message to all shell users.)

Files added since the earlier file system was saved must be created again and then added again.

If the physical file system owning the root fails, or if the root file system is unmounted, the operator must restore the root file system. A superuser who is defined with a home directory of /; (root) can also restore the file system. All work in progress when the failure occurred is lost and must be started from the beginning.