On 11/12/2005 at 10:10 PM Allison wrote:
Original topic: I'd like to get that Polymorphic to
build a small system.
I'm thinking Cpro CPUZ, Cpro Disk1A, Interfacer-II and Ram22. That will
build a z80, floppy interfaced, 256k with enough parallel IO to do an
IDE.
It's yours as a bare board for USD $10 and with 6 nice new gold-plated
connectors $20. Shipping extra. I seem to recall that Polymophic tied the
data in and data out together on their boards, but the MB doesn't show
that.
Current topic: Yes, IMSAI did offer a trade in.
...and that 4 slot expansion board is indeed labeled "IMS Assoc. Inc.".
I used to have the IMSAI floppy disk system too, but that wasn't engineered
nearly as well as the CPU box. One small power supply for each Calcomp
floppy with some blinkin LED's on a small front panel. I retired the IMSAI
FDC and Calcomps (the stepper motors eventually both shorted out).
Replaced the drives with Siemens double-sided units and used Don Tarbell's
FDC. Much improvement. I used that setup until I retired the system. The
MITS 4K DRAM boards got replaced with some SSM SRAM (lots of 2102's)
boards. The CPU was a Z80 board of uncertain vintage.
I suppose the whole mess could be replaced with a Rabbit CPU and a one-chip
FDC.
On a related note I've been doing some 1802 coding
and that 1977 NS*
box is still running Avocets 1802 assembler under cp/m. Still kicking
after 27+ years.
The 1802 was barely capable as a CPU. The only redeeming thing was that it
was static CMOS and could be run down to a DC clock rate. But that was
true of the IM6100, too, wasn't it?
Were there any hobbyist systems built around the Fairchild 9440 almost-Nova
chip?
Cheers,
Chuck