Disk Sort provides the current, established sorting technique, suitable for most sort/merge applications. Intermediate storage is allocated on disk devices and the sort size is limited by the allocated disk space plus secondary extents automatically obtained by the sort.
MAXSORT, MFX’s maximum capacity sorting technique, is not limited by disk space availability. MAXSORT determines how much data can be sorted using the available disk work space and divides SORTIN into SORTWK-manageable segments; the sorted segments are stored on tape or disk for a later, automatic merge. MAXSORT makes all the Disk Sort operational optimizing features and modern programming options available to large sorts, and additionally provides an enhanced breakpoint/restart capability for greater scheduling flexibility--you can stop MAXSORT processing at selected intervals without loss of sorted output.
PARASORT improves elapsed time performance for sorts whose input is read from a multi-volume tape data set and/or concatenated tape data sets. The performance improvement from PARASORT is a result of processing the SORTIN input volumes in a parallel fashion. PARASORT requires two to eight times the current number of tape units, depending upon resource availability and the degree of improvement desired. PARASORT automatically manages the tape units and minimizes the use of the tape drive resources by deallocating excess tape drives during initialization and releasing all the extra units at the end of the sort input phase.