hp proprietary uP history (9825 uP?)

From: Joe R. <rigdonj_at_cfl.rr.com>
Date: Mon May 3 08:55:39 2004

At 06:16 AM 5/3/04 +0100, you wrote:
>> Firstly, are the 9825 and 9845 processors the same part?
>I have a 9845 which is on the 'to be investigated' list. I will hopefully
>be pulling it to bits (non-destructively) soon. I've not done much on it
>yet, but from what I remember there are 2 processors in there.

  There are unless you got the optional Hi-Performace bit-slice CPU. One
was called the LPU (Language Processing Unit) and the other called the PPU
(Peripheral Processing Unit). The LPU handles the BASIC interpreter and the
PPU handles all of the system I/O. Go read my HP 9845 webpage at
<http://www.classiccmp.org/hp/hp9845.htm>. Interestingly HP found that the
dual CPUs didn't improve perfromace very much so they dropped one of them
on the 9835 and found the performace was almost as good. You can read about
that on the 9835 page.

  For more information about the HP 9825 go look at my HP 9825 page at
<http://www.classiccmp.org/hp/hp9825.htm>. See
<http://www.classiccmp.org/hp/hpdcalc.htm> for links to all the desktops


>One is a metal-heatsinked hybrid. It looks a lot like the one in the
>9825, but I don't even know if the pinout is the same, let alone the
>microcoding. The other is a set of 3 boards called the 'Sandwich'
>according to one of the lables on the chassis. There are 4 40 pin chips
>(which I will lay odds are 2901s), some microcode PROMs, and lots of
>smaller chips.
Received on Mon May 03 2004 - 08:55:39 BST

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