SORT has extensive internal error recovery ability for irrecoverable I/O errors that occur when a sort disk file is accessed. If such an error occurs, SORT issues the following message:

SORT ERROR #nn: IRRECOVERABLE I/O ERROR ON <sort file name> FILE

The nn is a number from 10 through 14, and the sort file name is the name of the internal sort file that is in error. SORT then waits for an OK or DS system command. If the operator requests error recovery by entering OK, SORT attempts to recover. If the operator responds by entering DS, SORT is terminated.

The sort disk files under discussion are the work files, which contain the data being sorted, and the control file, which contains control information for SORT. These two types of files are described under “Sort Files.”

I/O error recovery depends on the file and the kind of error encountered. The degree of recovery possible is always dependent on the request that SORT carry out error recovery for the program. Error recovery is never attempted beyond one level of recovery. If recovery is attempted while recovering from a prior error, SORT terminates. The primary areas of error recovery are described in the following paragraphs.