OSI 560Z: DEC PDP-8 clone using 6100 & 6502

From: Scott Stevens <sastevens_at_earthlink.net>
Date: Sat Jul 17 22:56:23 2004

On Sat, 17 Jul 2004 17:38:34 -0700 (PDT)
Dave <dfnr2_at_yahoo.com> wrote:

> Hello,
>
> Having recently acquired some 6100's (I know they're
> lesser than the 6120), I thought I'd try a PDP-8
> project (I remember seeing these, but never got to
> play with one.)
>
> Ohio Scientific had a board--the 560Z--which contained
> a 6100, a 6502, and a Z-80. The 6502 was
> "microprogrammed" to emulate the PDP-8 IOT codes, and
> OSI claimed that it was fully compatible. Has anyone
> played with one of these suckers? How good was the
> emulation? Does anyone have any info on the
> schematics of that board, or the 6502 firmware? Or,
> does anyone have an unused 560Z, working or not,
> they'd be willing to part with?
>
> I'm also aware of the SBC6120; I plan to order one of
> these soon.
>
> Thanks,
>
> Dave
>
>

I have quantities of the 6100 processor chip (new in tubes) and have
been wanting to do a project with them as well. I have located all the
datasheets for the family and also the info for the Intercept and
Intercept, Jr. computers, which use the 6100. The serious constraints
of the 6100 processor are the small memory map. But with it's static
CMOS design it's a cool 'breadboard' computer because you can clock it
down to zero hertz.

What I've wanted to build with the 6100 is a switchpanel computer for
hand coded machine language. To relive the memories of when I
bootstrapped a PDP-8e to do my 'Introductory Computer Programming'
programming assignments at Hamline University in St. Paul, MN in 1978.
I was the only person who finished the FOCAL programming assignments
because I was the only person who learned how to bootstrap it to load
FOCAL off paper tape. Everybody else just turned in the FORTRAN
assignments.

Scott
Received on Sat Jul 17 2004 - 22:56:23 BST