As my memory serves, there was a class given by the Southern California Computer Society (SCCS) in which the disassembled the Altair Basic (not sure if it was the 4k or 8k version) and used the output of that disassembly for the class. There was a guy who had the complete annotated (by the class) of the source as printed out copies in his trunk, which he just handed out to anyone that asked for it.   This was somewhere between 1975-1978 (76-77 most likely) when I was a member of SCCS. Bob On 4/3/2025 3:13 PM, Chuck Guzis via cctalk wrote: -- Bob Grabau http://www.astrohbg.org http://www.cherrysprings.org Our Star Party for 2025: June 19-22, 2025 at Cherry Springs State Park, PA

Hi, (First post, so go easy on me.) Perhaps what we have is not so much the release of the 8080 instructions, but the comments and, for what it's worth, the variable and storage names. This surely gives an insight that a disassembly, even an annotated one, just can't give? Cheers, Brian.

Perhaps, although at LCM (long before the "+L" was added--or we opened to the public) we built it on the 2065 running Tops-10 v7.04. Architecture is architecture, after all. [ snip ] Allen and Gates began programming on the PDP-10 in 1970, when Paul was a junior and Bill was a freshman. They were good enough that after Paul graduated, they (along with 3 of their friends) got jobs programming the PDP-10s for the control systems at the Bonneville Power Adminstration for the summer of 1971. As for Paul's 8080 simulator, it was indeed made up of Macro-10 macros (which can be very sophisticated) which processed 8080 assembler into user-mode UUOs and a set of UUO routines which perform the work defined for each such 8080 instruction. The simulator is used by including its source code with the 8080 source code to be executed, assembling everything, and executing the result. It's a marvelous piece of programming which utilizes the PDP-10 architecture to its fullest. Rented time on while they were located in Albuquerque, then outright owned once they moved the company to Bellevue. A friend of mine, M$ employee no. 11, was one of the developers of the other macro packages for different micro acrchitectures. Rich [1] For the non-PDP10 folks out there, "UnUsed Operations", later "Unimplemented User Operations", op codes left intentionally undefined which when encountered in the instruction stream check to see whether there is a trap defined, so a system-style subroutine call. Opcodes 001-037 are avaiable to user programs, while 040-077 are defined for the operating system.