HP 9825a

[Geoff Quickfall]

It is HP and it does calculate but it is not quite an HP calculator. I am referring to my HP 9825A desktop computer.

I restored the keyboard about five years ago and Larry Atherton (see post in general forum about Larry) restored a machine my tape drive to accept that 100 tapes. He also supplied five tapes with statistical, mathematical, testing programs for the HP to 9825A.

He was extremely helpful filling in blanks that the manuals do not cover.

With that in mind, I have acquired to tape drives, a master and slave HPIB, 8 inch floppy drives; the 9885M and the 9885S. Now I have to find the correct HPIB cable to attach these to my 9825A. Also do need a ROM module for plugged in to the front or do they need dedicated PCA boards internally.

I would appreciate any help identifying the requirements to attach these disc drives to the 9825A.

Thanks in advance; Geoff

[LinusSch]

I am not an expert, but I have handled about a dozen GPIB cables in my day. I have never encountered any difference between any of these cables other than length and one that was damaged.

I'm fairly sure the cables are the exact same for HPIB? I have a vague memory that some computer communicating with some disk drive may run the bus at a higher speed, which does place stricter requirements on the cables but I don't think there are any special ones - just keep the length somewhat short, I guess.

[Maximilian Hohmann]

Hello!

(11-22-2024 09:12 AM)LinusSch Wrote:  I am not an expert, but I have handled about a dozen GPIB cables in my day. I have never encountered any difference between any of these cables other than length and one that was damaged.

Electrically they should all be the same, but there exist "custom made" ones for specific calaculators and their peripherials.

This one is from my HP-150 and has exactly the right length and connector placement (note that the connector casings are different!) for connecting the computer to a disk drive placed underneath.



I have seen similar cables with HP-9000 series workstations that originally consisted of a stack of "boxes" containing the CPU and various peripherials, all connected via HP-IB.

So I guess that there must be some custom cables for the HP-9825A as well. But a longer generic cable coiled-up behind the calculator works perfectly well, it just doesn't look so tidy!

Regards
Max

[Martin Hepperle]

(11-22-2024 05:37 AM)Geoff Quickfall Wrote:  It is HP and it does calculate but it is not quite an HP calculator. I am referring to my HP 9825A desktop computer.

I restored the keyboard about five years ago and Larry Atherton (see post in general forum about Larry) restored a machine my tape drive to accept that 100 tapes. He also supplied five tapes with statistical, mathematical, testing programs for the HP to 9825A.

He was extremely helpful filling in blanks that the manuals do not cover.

With that in mind, I have acquired to tape drives, a master and slave HPIB, 8 inch floppy drives; the 9885M and the 9885S. Now I have to find the correct HPIB cable to attach these to my 9825A. Also do need a ROM module for plugged in to the front or do they need dedicated PCA boards internally.

I would appreciate any help identifying the requirements to attach these disc drives to the 9825A.

Thanks in advance; Geoff

My 9885 disk drives use a 16-bit parallel GPIO interface - not HP-IB.
The proper interface is 98032A OPT 085 "9885 DISK".
I guess that the standard 98032A GPIO Interface is electrically the same, only with a different connector.

For disk access you want a 9895/9885 FLEXIBLE DISC DRIVE module 98228A if your 9825 is "T" model (many "A" or "B" have been converted to "T" models, check the amount of installed/accessible RAM).
Otherwise the simpler 98217A "9885 FLEXIBLE DISK DRIVE" module or the 98218A "9885 FLEXIBLE DISK ROM" module.

The 98228A can also format disks, the 98217A and 98218A require formatting software on tape.

There is also a 3rd party ROM module "Mass Storage" by "Structured Software Solutions" (SSS). Its capabilities are similar to HP's 98228A.

The slave disk drive is dumb - it cannot work without its master.

I have attached my notes on the commands available in the 98228A and the 98217A ROM modules.

And it was called "Desktop Calculator", so that it could be bought in larger companies by an engineer without raising concerns in the computer/mainframe department.

Martin