Memory options for an HP 1000 (HP 21MX / 2112A)

J. David Bryan jdbryan at
Sun May 24 01:22:36 CDT 2015

On Saturday, May 23, 2015 at 17:48, Marc Verdiell wrote:

> I think I should retrace the path of technology evolution. Start
> getting it up with paper tape tests and BCS. That probably means working
> mostly in assembly and getting to know the most basic level of the
> machine. Which is just about what the doctor prescribed. 

Assuming that you have a working paper tape punch and reader, and the 
associated interface cards, then that's a very workable approach.

> I got a 7900 disk though (with cables and power supply, but no
> interface cards to go with it!). 

The interface is HP product number 13210A.  It's a two-card set; the card 
numbers are 13210-60004 and 13210-60000.  The I/O cable is 13210-60003.

> I'd love to get that one going later on. Then it would make sense to
> have the bigger memory to run disk based OS systems. 

The 7900A was supported through the final RTE versions.  However, you could 
run the disc-based DOS-III OS with just the hardware and memory you have 
(assuming that you add the 7900 disc I/O interface).  With the addition of 
a HP 12539 Time-Base Generator card and 8K more of memory, you could also 
run RTE-II on a 7900.  Neither DMS nor more extensive memory is required 
for these OS versions, which are substantial steps up from BCS in terms of 
sophistication and ease of use.

> By the way I also have a punched card reader which I just restored.
> Documation ML600, but the exact same model that HP re-branded I
> believe. 

That's either the HP 2892A or 2893A, depending on whether it has a TTL or 
differential interface, respectively.

> Do you know which interface cards I need to connect it to the HP-1000? 

The interface is the HP 12924A, which was specific to the 2892A card 
reader.  The 2893A was supported only on the HP 3000, as far as I know.

> I suppose one of the 16 bit IO ones with a driver to go with it?

The general-purpose TTL interfaces apparently would not work.  Drivers for 
the card reader were supplied with the various OSes.

> Sorry to keep picking your brain, but that is so much more efficient
> than trying to piece it together (usually wrong at first) from an
> disorganized pile of documentation!

I'm glad that I can be of help.

                                      -- Dave

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