22 Jul
2016
22 Jul
'16
6:58 p.m.
On 2016-07-22 9:17 PM, CuriousMarc wrote:
Unfortunately, I have the older ROM, the HP 98217A.
Says 9885 Flexible Disk
Drive on it (duh). Only this 9885, single side low density 8" drive,
connected with the parallel interface and a special cable is supported. And
indeed as Tony says, to start from a blank disk, you need a tape cartridge
that has the "disc system" on it and run an initialize program to copy files
on the first disc sectors. If you don't have a copy of that cartridge then
you are hosed even with that ROM. So I am hosed twice: I don't have a 9885
drive and I don't have the cartridge. And I suspect a cartridge that's
readable doesn't exist anymore.
The newer ROM is the HP 98228. Which can ONLY work in a later HP 9825T (not
the A nor the B), and can drive the aforementioned 8" 9885 with the parallel
interface, and also the 9895 double sided double density double drive via
the HP-IB interface. But only with the "revised" HP-IB interface, not the
original interface. Very picky that ROM. Bu for the 9885 disc, it does not
have the cartridge requirement (yeah!). I have the 9825T, the 9895 drive,
the revised interface, but not the right ROM. Hosed again.
The details are in the 9825 Disc ROM Manual:
http://www.hpmuseum.net/document.php?hwfile=1864
Marc
On the hpmuseum.net page for the 98217A ROM here is an image of what is
reputed to be an initialized diskette for use with 9825 and 98217A
http://www.hpmuseum.net/display_item.php?hw=166. When I get my 9825T I
will look into 9885 emulation, I don't think it will be too difficult
but you may still need a GPIO unless I build the whole thing onto a
plug-in card I don't think the GPIO would be too difficult to clone.
But ideally I would still like to get access to a 98228A ROM to dump and
clone it, even though it is bank switched it should still be possible.
Paul.