Purposefully fudged schematics (was: Wire Rope ROMs (Was: back to
ard at p850ug1.demon.co.uk
Thu Jan 4 18:48:38 CST 2007
> In article <B9639BAE3F34504E83FEEDD71D4AFB460A660A at mail.bensene.com>,
> "Rick Bensene" <rickb at bensene.com> writes:
> > [...] Wang is also
> > famous for purposefully putting errors into published schematics to
> > throw off competitors who would use such schematics to reverse-engineer
> > how the machines work. [...]
> Wow, I'd never heard that story before. Interesting!
I am wondering what the use is of a schematic that contains deliberate
errors that are significant enough to stop the machine from working. OK,
you can't use it to make a copy, but you surely can't also use it to
repair the real machine (what do you do if the faulty part is a section
that has errors in the schematics?).
> How many other companies did this back when schematics were pretty
> much leaving the machine laying naked in front of you?
I've never seen any 'deliberate errors' in HP, DEC, Tekky, etc diagrams.
There's a very obvious error in the PERQ scheamtics book (I think in the
tablet diagrams) where a 3 terminal regulator is drawn with all 3 pins
tied to ground, but if you don't spot that one, you shouldn't be fixing a
computer in the first place. And I don't think it's a deliberate error
because it is so obvious.
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