On 3 April 2016 at 02:50, Andrew Rowley <[email protected]> wrote: > One question that puzzles me (maybe it's my lack of an application > programming background): Why is sort used so much on z/OS?
As others have pointed out, sort on z/OS (whether IBM's or other vendors') can be used for all sorts (heh) of general I/O with high performance. But "sort" also covers the notion of merge, and more generally of collation. Many languages have constructs that implicitly sort, and all relational (and probably other) databases will sort implicitly as required, whether they implement their own sorts, or call the system one. The database product I worked on 20 years ago had three levels of sort: for a few rows it did its own in-storage sort, for thousands of rows it did it's own with work files, and for bigger stuff it called the system sort. Today those thresholds would be x10 at least because of much cheaper and bigger main storage, but the concept holds. A historical reason for use of sort on z/OS may be that "way back in the days of steam powered computing", main storage was very expensive, disk was expensive, and tape was cheap. It was not unusual for sort to use tapes for work files; how else would you sort tens of millions of records on a machine with, say, 512 kB of storage and a few hundred megabytes of disk? UNIX and indeed most other systems didn't start out doing commercial data processing, and to this day don't do batch processing very well. Tony H. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
