Internal HP docs on 9845 sys?

F.Ulivi fulivi at
Sun Feb 21 03:56:34 CST 2016

Hi everyone,

I've been working for the last few months on implementing the MAME
emulator of HP 9845B system.
In case you're interested, have a look at MAME development page at
My emulator mostly works, the main missing thing now is the graphic
mode and the ability to load optional ROMs.
Anyway, I'm posting here because I'd like to ask you a few questions on
HP docs.
The last thing I worked on for this emulator is the "TACO" tape driver.
I reverse engineered it
entirely from sw & the (scarce) docs available enough that it works.
So here a few questions for you:
* Back in the days, what was the HP approach to document
internally-developped chips for its own
  sw developers? I mean, was there a kind of programmers' guide for TACO
chip? Is there any hope
  someone scanned it and made it available somewhere? I know that for
hybrid processors HP made
  an internal manual titled something like "how they do dat" manual...
* Just out of curiosity, what a big company like HP does with its
"historical" documents? Do they
  have an archive where they keep documents & sw from, say, the 70s? Or
do they throw everything away
  when there is some kind of company "shake-up" such as big layoff
phases, closing of a site, merging
  and splitting of divisions?

Thank you.

-- F.Ulivi

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