27 Jun
2012
27 Jun
'12
12:54 p.m.
Hi all --
Picked up a (mostly) complete HP 9885M (8" floppy drive) set up for my
I know it. I also know how mcuh is missign form the documentation.
The interface to the host is a 16 bit databus and some control lines.
I've eyt to finnd any description of the command set, etc. You can deduce
some of if from the HP900/200 Pascal technical docs (on bitsavers), but...
HP 9825 computer. I have the 9885M drive itself, a
98032A interface,
and the "Flexible Disk Drive" ROM pak for the 9825. I am unfortunately
missing the "9825A Disk System Cartridge" tape (hp p/n 09885-90035).
Than you have problems. The ROM is essenmtially a bootstrap. You need the
system tape to format new disks and write the OS onto them. There was a
later disk ROM that waslarger (it's one of the few bank-switched ROMs for
the 9825), but belive-it-or-not disks fromated with that are not
compatible with the older one AFAIK.
Any ideas if this has been archived anywhere? I
haven't found it in my
Not that I know of. There was, IIRC< no way to copy binary programs on
the 9825 (well, you could with a 9877 external tepe memory unit, but they
are ridiculously rare, and the itnerfaces/software for them even rarer).
So there was no real way to archive this system cartridge :-(
searches. (Not that I currently have any means to get
it onto my
9825...) Looks like this is actually required in order to format disks.
Sigh...
Unfortunately, the drive appears to be failing the built-in diagnostic;
there's a single LED that goes on when the test starts and it's supposed
to go out within a minute if the diagnostic's passed. The LED on mine
just stays on permanently. Unfortunately that's the -only- diagnostic
indicator on the unit. I've read through the service manual and unless
I'm missing something it doesn't really describe how to go about
narrowing down the problem. There's a flowchart that basically says "if
the light doesn't go out, it's a problem with the controller in the
drive unit" which seems fairly obvious...
I asusme you've looked at the the schemaitcs and pnaiced. There are a few
boards of stanadrd logic, things like the disk data shift registers, data
separateor, etc. And then there's that board with the HP custom
'nanocontroller' and firmware ROms on it. AFAIK HP never docuemtned this
nanocontroller, the instruciton set is not known (I would love to be
wrogn about this) so tryign to disassabmble the firmware is a
non-starter.... And without knowimg what that firmware is doing you are
essentailly working blind.
-tony