25 Dec
2009
25 Dec
'09
8:20 a.m.
Tony Duell ????????:
That's probably it. It's been a while since I'v read the data sheets.
And I seem to recall something GPIB from other sources, like
Fairchild, AMD and NatSemi, as well.
If the design is 'open', then presumaly you could mofify it for whatever
storage device you want. And surely it would be better to have a working
desing for _any_ modern-ish storage device rather than debate about which
device to use.
I was suggesting a bit more along the lines of "It would be nice if a
developer wouldn't focus solely on one type of storage but rather
design something where any storage medium could be easily added."
There tends to be way too much of a laser focus on favorite storage
media, i/o, interfaces, etc. and others end up having to reinvent the
wheel, even if the design is open.
You're right! And I've seen it elsewhere, as well. There was a couple
of detailed notes going around BBS's. Xebec also published their own.
No, you're right: They're Motorola in the HP controllers. MSC and
Xebec used Intel. I didn't trap the tired memory errors. Sorry.
(Wouldn't it be nice to have 8bit processors w/ 500MHz to 1GHz clocks?)
Perhaps the
8291 used less code on the microcontrollers? Or perhaps it
could do seomthing on it's own, unlike the 9914, such as assert NRDF
when it's databuffer was full? Come to think of it, wasn't the 8291
almost "smart", like a hard coded microcontroller?
I think you're thinking of the 8292, which was an add-on chip to the 8291
to give contrtoller functionality (the 8291 on its own could talk and
listen, but couldn't act as a controller). That chip was clearly a
programmed 8041 or 8042. I still
think it would be a useful project for somebody to make a=20
HP-drive-emulator. Mot using a PC, but using a microntroller, HPIB=20
buffers, the minimal (if any) logic you need to handle HPIB, and a CF=20
card. Make it 'open' and I'll build several...
Or even a SATA, PATA, USB storage interface. Such a stand alone
emulator would be very useful. There's a
fair description of the Amigo protocol floating around as
well as the CS80 spec as a PDF on Bitsavers. Since all the HP drive
The amigo protocol is in some of the HP drive service manuals. controllers are built around Intel
microcontrollers, shouldn't be too
Are they? While I'll believe (if shown) that such a device exists, every
HP drive I've been inside [1] uses a Motorola processor. An 6802 in the
82901, 68B09s in most others and a 68000(!) in the 9145 tape drive.
If this is a 9133XV with the HP controllers (6809 + 9114, etc), then I
have unofficial scheamtics. The floppy controller is actually quite
simple -- most of the logic is on the top board, the lower board contains
the master clock and disk data separator. Apart from the EPROM (which is
the sama as in a 9121 IIRC), there's nothing remotely custom in there.
It has the separate HP HD and FD controller boards. It appears to work
normally except that it is unable to read any floppies. Changing the
drive did not change anything about that. Beyond that, no idea,
although it may be the data separator board. One Of These Days, I'll
dig it up, thaw it and see what else I can find.
==
jd
Fortune's Real-Life Courtroom Quote #52:
Q: What is your name?
A: Ernestine McDowell.
Q: And what is your marital status?
A: Fair.