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Re: IPS for IBM-PC? (Was: AO-40 Telemetry News.. IHU-Keps??)

Howard Long wrote:

> Now you're showing your age.

Yes, but I'm remarkably well-preserved. 

>> I hand-keyed in the 14k of object code of the FigFORTH CP/M
>> interpreter into my TDL Zitan (saving it as a 1200 baud audio signal on a
>> casette tape, no less)
> (a) Now that's an achievement. Not all in one go I hope.

No, it took about a week...three days of keying in and three days of launching
it, letting it run until it fell over, and then inspectiing the interpreter
registers to see where the tire-tracks left the road, then hand-checking the
code in memory against the printed assembler listing until I found the typo,
then saving the updated image back to cassette.   

> In '76 on an old 2 chip General Instrument CPU (the
> first computer I built) I did this with switches and LED's. Lucky it only
> had 256 bytes of RAM....

Closest I got to that was with the Xitan, which didn't actually *come* with a
keyboard. It did have two built in serial ports which became the monitor console
(you young'uns can think "BIOS" for "monitor") on power-up. But being recently
unemployed I could no longer borrow a portable terminal from work to talk to it,
so I built a serial "keyboard" from a UART chip, a dip switch and a pushbutton.

After a few days of poking around with that, I got hold of an RTL-logic ASCII
keyboard (from some old Burroughs box that was being scrapped) for $10, used a
logic probe to puzzle out the power and output lines, and wired it to the

 73 de Maggie K3XS

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