Re: HP App Notes 201-X series wanted

Steve Leibson

Hi Marc,

Yes, half of the words in the System Programming ROM are devoted to the Store(A$) command. It was the only way to get a listing back into the machine from a saved ASCII printout. I never imagined that the Loveland Instrument Division would use it to programmatically combine HPL program subroutines into completed ATE programs, but it proved very popular for them. It seemed so simple: just jam a line into the keyboard buffer and smack the "store" key with a JSR call. But there were several exceptions to the ASCII program listings compared to the stored program and all of the exception checking ended up consuming half of the ROM.

Chris Christopher was in charge of the HP 9825 firmware effort and he was not at all pleased with my tinkering. He was afraid my abuse of the 9825's live keyboard feature would surface a latent bug in the main language ROM and so he repeatedly told me "Any bugs you find are yours!" None were found, until the 9825S/T conversion turned up a latent bug in my own code, but not in the Store(A$) command. It was in one of the special 98036A register-access commands I'd added. There were two writes misdirected at ROM locations. In the 9825A/B, writes to a ROM address counted as NOPs, so no damage was done. In the 9825S/T with full 16-bit addressing, RAM occupied those locations and the conversion team had to debug the problem of two RAM locations being mysteriously zeroed out for no apparent reason. "Any bugs you find are yours!" is what I told the conversion team. "It works fine on the 9825A/B."

By the way, the Systems Programming ROM was my first and only commercial software-only product. That's how we did it back then at HP. Design and debug hardware one day, run a lathe or mill the next day (under close supervision by the machinists who hated having engineers fooling with a power tool), write code the day after. What's all this specialization stuff?


On 1/23/2020 5:03 PM, CuriousMarc wrote:
Just added my scan of the missing AN 201-06 Computer Communications HP 9825 - HP 1000. One is a large (45 MB) pdf file with high resolution scan, the other one is a smaller (4.5MB) one with searchable text. They describe communication over HP-IB and Serial, with ways to upload and download program and data from the 9825 to the HP 1000 running FORTRAN helper programs. It can be done, but pretty contrived as expected, I suspect not many people went through the trouble. It uses Steve Leibson's system programming feature "store" command to download programs (Steve did I get this right that you put that function in?). Many thanks to John Lawson for a) rescuing the manual and b) driving it all the way from Nevada to California. Now that's customer service!
Steve Leibson

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