HP9877 External Tape Memory

From: Joe <rigdonj_at_intellistar.net>
Date: Fri Mar 9 21:58:59 2001

At 06:31 PM 3/9/01 +0000, Tony wrote:
>>
>> Tony,
>>
>> You must be forgetfull in your old age :-) We've talked about the 9877
>> before. I have two of them. Both of mine have four drives in them. They
>
>I remember you mentioned you had (at least) one, but as mine was still
>hidden in the depths of my workshop, I don't think I said much about it.
>
>> were also available in a two and three drive versions. Each drive after the
>
>The printing on the back panel telling you what fuse to fit refers to OPT
>002 and OPT 004, which I would guess are the 2 and 4 drive versions. I
>don't see a reference to a 3 drive model, but it certainly could exist.


>
>> first one was a option so you had to order three options to get four
>
>Sure. It's obvious I could add extra drives to mine if I had them.

     Right but I think the original price was something like $900 each!

>
>> drives. Basicly the 9877 isn't designed as a mass storage unit although it
>> can be used that way. Originally it was designed to mass produce tapes at
>> HP. You can start the copy and it will copy from one drive to all the other
>
>That really suprises me, based on the lack of 'smarts' in the unit.
>
>There ae only 2 'big' chips -- 24 pin ones -- on the controller board.
>I've identified them as 74116 latches. There's no processor or memory in
>the unit. I suppost it's possible there's the logic to do a bit copy
>between tapes -- I will find out when I dig deeper into the unit, I guess.
>
>> drives in the same box without tying up the calculator or the interface. I
>> do know that they used a special version of the standard HP 98032 16 bit
>> parallel interface, I was able to find that much out from the guys at NASA
>
>Interesting and surpising. I suppose you can 'fake' a bidirectional bus
>using the open-collector outputs of the 98032, by linking them to the
>inputs as well as to the bus. Seems a little odd.

   HP used the 98032 for a lot of things like that. I know it was used on
the 9866 printer (98032 option 66), the 9885 disk drive (option 85), one of
the paper tape punches, one of the paper tape readers and a LOT of other
peripherals. I've been thinking that I'd like to find out more about the
various items that used the 98032 and how the 98032 was configured for each
one. I do have schematics for the option 66 version and one or two others.

    BTW if anyone finds a 98032 interface that says option (anything) or a
manual for one of the optional 98032 interfaces please let me know about
it. I'd like to add it to my collection to study or at least get the
jumpers settings and the like from it.


>
>> that have one. I think the only thing unique about it was how some of the
>> jumpers were set and the connector that mated to the 9877. The guys at NASA
>
>My guess (without any proof) is that it uses the DMA feature of the
>interface.
>
>If you are _sure_ it's a 98032 interface, then that's a great help. I
>have the operating/service manual for that, so it will give me an idea
>as to the sort of signals to find on the I/O connector of the 98032.

   Yes, I'm sure. Somewhere I have a picture of it and you can read the
model number on the interface. BTW I'm pretty certain that this one is
optioon 77. You'll notice that option number is allways(?) the same as the
last two digits of the model number of the device that it attachs to.


>
>> wouldn't open their interface up and tell me what the settings were. The
>> 9877 did not use any of the built-in calculator or interface commands.
>> Everything was controlled by software programs that came on a tape. You
>
>That would seem to be supported by the low-level nature of the interface
>(in that iu's not going to look like a standard character device).
>
>> of the interesting features of the 9877 was that it would copy ANY tape
>> file, Binary, Protected, anything! Sort of like a Copy II PC card if you've
>> ever used one of them. I'm sure that was because it was designed to be used
>
>Sure. This, again, comes from the fact that the 9877 just reads/writes a
>raw bitstream. It's up to the calculator nd software to turn those bits
>into bytes, and then into blocks and files.

    Exactly. That's why it's able to copy any tape no matter what machine
it came from.

>
>> that I have. It belongs to NASA. However their tape has deteriorated too
>> and now their 9877 in unusable.
>
>Pity :-(. I assume this means the software is totally unavailable. I got
>my 9877 from a radio rally (hamfest) and the seller didn't know anything
>about it. There was certainly no program tape anywhere near it.

    I got my two 9877s under similar circumstances. I've spend years trying
to find out more about them. I did finally find one short manual. I think
it was the installation manual. And I talked to the guys at NASA and they
were able to tell me a little bit. Then the ex-HP guy told me about them
being used in the factory. So I've pieced together a little background on
them but so far I haven't been able to locate a tape. Given how badly the
HP tapes deteriorate with age, it's unlikely that I'll ever locate a
useable tape for the thing.

>
>>
>> The tape drive is the same as that used in the 9815, 9825, 9835, 9845
>> and 9831.
>
>I've not dug out my 9825 (or 9831) yet, but I can confirm the drive is
>_identical_ (including the PCB) to that in a 9815.

    Do you have a 9831? That's a RARE bird! I have one but it's the only
one that I know of. It was another item that was only listed for one year
in the HP catalog. It has an interesting background. It was a temporary
replacement for the HP 9830 (both ran BASIC). But the following year HP
released the 9835 and 9845 so they dropped the 9831. HP says that there
was a big demand for a replacement for the 9830 and that was why they
developed the 9831 but if that's true then I would expect to find more
9831s around. As I mentioned above, the 9831 was a replacement for the
9830. However it not only did everything the 9830 did but it also had ALL
of the 9830 option ROMs built in! But one of the most interesting things
about the 9831 is that it's actually a 9825 with different ROMs! That's
right you can pull out the OS ROMs in an early 9825 and slide in the 9831
ROMs and the machine is now a 9831! The ex-HP guy told me that many of the
HP engineers used to keep a set of both ROMs and would change them at will.

   Tape drives: Yes those are a standard design tape drive that HP used in
lots of stuff. I once worked on a spectrum analyzer and it had the
identical drives in it. I believe there are only two basic tape drives
used in HP equipment (other than the micro cassettes). This design and the
earlier ones that were driven via the capstan. The capstan type were used
in the 9865 Tape Cassette, the 9821 and 9830 calculators and some of the
other early equipment.

    Joe

>
>-tony
>
>
Received on Fri Mar 09 2001 - 21:58:59 GMT