Potpourri

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

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.

Click here for the article.

IOCE – Input Output Compute Element channels

Here is a chapter from a 1968 training manual covering operation of the 9020 IOCE Multiplexor and Selector Channels. The IOCE is a S/360 Model 50 with some added bells and whistles, so the descriptions are also applicable to the standard Model 50 channels.

Click here for the document.