I did a tour of duty as a CPU logic designer at Amdahl. The POO was my bible, although it was the 370 version in those days. The thing to remember about ISA specs like this is that they are works of fiction. The contract goes: “If you programmers are willing to pretend this is how the machines work, we will build a machine that pretends to work that way.” That concept is the key innovation of the 360 system architecture, attributed to Gene Amdahl.
After leaving Amdahl I worked for a while in Electronic Design Automation. One year at the IEEE Design Automation Conference I met a random person at a happy hour who was an ex-IBM OS programmer. He said that he once spent a year rewriting a part of the OS to use a particular instruction entirely because “Amdahl didn’t have it yet.” Says I: “When was this?” ... “Ah, at that time part of my job was adding that instruction to the Amdahl CPU.”
The conversation felt like an old Mad Magazine “Spy vs. Spy” cartoon. We were both bemused.
By pure random luck and if you know, has Amdahl's UTS survived anywhere? Mainframe software seems to simply disappear into the void after its useful life is over.
After leaving Amdahl I worked for a while in Electronic Design Automation. One year at the IEEE Design Automation Conference I met a random person at a happy hour who was an ex-IBM OS programmer. He said that he once spent a year rewriting a part of the OS to use a particular instruction entirely because “Amdahl didn’t have it yet.” Says I: “When was this?” ... “Ah, at that time part of my job was adding that instruction to the Amdahl CPU.”
The conversation felt like an old Mad Magazine “Spy vs. Spy” cartoon. We were both bemused.