AAEC implementation of and modifications to release 21.6 of the IBM360 operating system.

This report describes the implementation of and modifications to the IBM360 operating system for release 21.6. The system generated was Multiprogramming with a Variable number of Tasks (MVT) with the Houston Automatic Spooling Program (HASP) if, version 3.1. The report makes extensive reference to the AAEC report on modifications and additions to the IBM360 operating system for release 19.6