HP 7970E - interest to split?
elson at pico-systems.com
Fri Sep 29 11:33:00 CDT 2017
On 09/29/2017 10:56 AM, Henk Gooijen via cctalk wrote:
> On a related note my plan is to make a USB-based, Pertec-compatible
> controller for it. Not sure how SimH connects with peripherals so I'm
> /very/ eager to talk with someone familiar with its workings. I'll also
> release all the board files and firmware as open-source. Timeline as always
> is completely unknown, though I do have a now-vested interest in making it
MANY, MANY years ago I got a surplus Pertec key to tape
system that had a 7" 9-track 800 BPI NRZI drive connected to
hardwired logic. You could key in data, verify data by
re-keying it, and read back data to a panel of light bulbs.
It had core memory for the data buffer.
I found the right place to slice the sections apart and have
what was pretty close to the unformatted Pertec interface.
I then wrote a mostly software-driven interface to read and
write tape blocks on my CP/M Z-80 system. I created tapes
and took them in to work to map them and got it to write
ASCII text files in VAX ANSI-D format. It really was not
that complicated. This was a read/write drive with only a
single data gap. So, to write and check a record, you had
to write it, back up and read it. I used it for making backups.
I think you could use a Beagle Bone and the PRU
microcontrollers in it to do a Pertec unformatted interface.
The only issue is that the PRUs have a fast local memory of
very limited size. There is a way to open a memory
map to the ARM system memory from the PRU, although the
shared memory is 12 K bytes, which might be enough to handle
I did an FPGA-based adapter to Pertec formatted interface
using the parallel port. (Slow, but I already had all the
FPGA and computer side infrastructure to make that work.) I
have some CDC Keystone (92185) drives.
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