Potpourri

1964 IBM System Journal - A formal description of SYSTEM/360

Click here for the article.

I believe this document would be a great aid to anyone writing a S/360 simulator. It seems to go way beyond the Principle of Operations. It “expressly specifies the state of every register or facility accessible to the programmer for every moment of system operation … The work is based on the SYSTEM/360 manual and on interpretations and revisions furnished by the system architects”.

It even covers operation of the Emergency Pull Switch and Machine Check (i.e. hardware failure) interrupts, as well as the state of key blinkenlights.