HP9877 External Tape Memory

From: Joe <rigdonj_at_intellistar.net>
Date: Thu Mar 8 23:14:13 2001


   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
were also available in a two and three drive versions. Each drive after the
first one was a option so you had to order three options to get four
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
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
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
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
have to have the software tape to use the 9877. AFIK the 9877 could be used
with any calculator that could use the 98032 interface IF there was
software available to operate it. I know there was software available for
the HP 9825. I expect it was available for the 9835 and 9845 as well. One
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
to mass produce tapes. An ex-HP calculator engineer told me that they were
still using 9825 and 9877s to produce tapes for the 9835 and 9845. The 9877
was originally used inside of HP for mass producing tapes and was only
listed for sale in the HP catalog in 1977. I guess not many were sold
because I've only found one other than the one that you have and the two
that I have. It belongs to NASA. However their tape has deteriorated too
and now their 9877 in unusable.

   The tape drive is the same as that used in the 9815, 9825, 9835, 9845
and 9831.

   I did have a description and some pictures of the 9877 on my website
However my ISP managed to wipe out my site and I haven't fixed it yet.


At 10:31 PM 3/8/01 +0000, you wrote:
>Does anyone know anything about the HP9877 External Tape Memory unit? I
>found one hiding in the back of my workshop while looking for something
>to raid a fan from. No, don't worry, the fan is still in the 9877 -- I
>found an old and dead PC power supply at the same time.
>Anyway, getting back to the unit in question. It's a standard HP case --
>the type that could be fitted with brackets and put in a 19" rack. On the
>front is the standard power switch and LED, and cutouts for up to 4 tape
>drives. Mine has only one drive fitted, though.
>On the back is a mains connector, voltage selector switches, a fan, and a
>50 pin amphenol connector. The latter is obviously to link it to some
>kind of host computer.
>Inside are 4 main sections :
>1) The tape drive. This identical to the one in an HP9815 calculator,
>although it has a different mounting bracket. The tape drive PCB (sensor
>amplifiers, read preamp, write switch) even has a 09815- part number
>2) The controller. It looks like this will only link to one drive --
>there's space for another 3 of them in the case as well. It's a large
>board full of TTL and analogue parts (the latter for the read amplifier
>chain and motor control, I guess)
>3) The interface. A small PCB with about 6 TTL chips on it. It has 4
>ribbon cables to link to the controller boards and a card edge to take
>the cable from the rear-panel connector.
>4) THe PSU. A standard-ish HP transformer and a PCB containing the sort
>of regulator circuitry you'd expect to find in a 9815 or 9825. In fact
>the PSU PCB has a 09825- part number, and is presumably the same as the
>one in a 9825.
>From a quick look at the boards, it appears that the interface is very low
>level (I don't think it even attempts to turn the bitstream from the tape
>head into bytes, let alone into data blocks). It also appears that there's
>an 8 bit bidirectional bus and some control lines on the host connetor.
>My first question is : What is this used with, and what interface is used
>(I don't think, for example, that it uses a standard 98032 parallel
>interface, even if it is used with the 9825).
Received on Thu Mar 08 2001 - 23:14:13 GMT

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