3 May
2004
3 May
'04
8:23 a.m.
At 06:45 PM 5/3/04 +0100, you wrote:
That would be cool! I have four or five 9845s but I don't think any of
mine have that option.
At 06:16 AM 5/3/04 +0100, you wrote:
There are unless you got the optional Hi-Performace bit-slice CPU. One
I think I may well have that. 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.
On the left of my machine is a board with one of the HP hybrids on it. I
assume it's a proccessor -- it looks very like the thing in my 9825 and
9831.
On the right there's a set of 3 boards, only one of which goes into the
main backplane. There's a little backplane on top that interconnects
these 3 boards. One of them contains 4 2901 chips (4 bit bit-slice ALUs).
Anohter contains what look to be microcode PROMs.
I assume the former is the PPU, the latter the LPU. I would certainly
describe my LPU as a bit-slice board -- do you know if the standard LPU
was an HP hybrid chip, a board of bit-slice chips or what?
I believe it was a hybrid.
I know little of the history of my 9845, other than when I got it it came
with 2 8" drives, a few 16 bit parallel interfaces, 3 HPIB interfaces
(!) a real time clock at least one RS232 interface and the rather
hard-to-find 9878 expansion chassis.
hard to find? Sheesh I find them all over. nearly every 9825 that I find
comes with one. I just passed one up in a scrap yard a couple of weeks ago.
Also passed up a couple of the RTC modules. The RTC modules with the IO
cable are cool. You can interface them to external devices and trigger the
devices or use the device to trigger events in the 9845.
Joe
For more information about the HP 9825 go look
at my HP 9825 page at
<http://www.classiccmp.org/hp/hp9825.htm>. See
I know the 9825 hardware fairly well...
-tony