I spent seven years doing maintenance programming for EXEC 8, the operating system kernel for the UNIVAC 1108. It was first demoed in 1967, and was way ahead of

I spent seven years doing maintenance programming for EXEC 8, the operating system kernel for the UNIVAC 1108. It was first demoed in 1967, and was way ahead of its time. By about 1972, it was running reasonably well. This OS had threads, symmetrical multiprocessing, and async I/O. Written entirely in assembler, it was not fun to work on. When it crashed, a dump was taken to drum, and the dump was then printed, producing a stack of paper about two inches thick, mostly just pages of octal numbers. Analysis involves pencils and colored highlighters, tracking pointers through memory. Here's the manual.[1] Amazingly, the descendant of EXEC 8, OS/2200, is still a maintained product, over half a century later.[2] There's even a roadmap out to 2033. [1] https://archive.org/details/bitsavers_univac1100tiveReferenceManual1966_36328697 https://archive.org/details/bitsavers_univac1100tiveReferenc... [2] https://en.wikipedia.org/wiki/OS_2200 https://en.wikipedia.org/wiki/OS_2200