[Coco] OS9 Pascal
gene.heskett at verizon.net
Sun Aug 12 20:57:10 EDT 2007
On Sunday 12 August 2007, RJRTTY at aol.com wrote:
>In a message dated 8/12/07 11:08:33 A.M. Eastern Daylight Time,
>gene.heskett at verizon.net writes:
>>The box? A Quest Super Elf board, RCA
>>1802 based. It had a whopping 256 bytes of ram, but had an S-100 buss, so
>>bought it a backplane, and 4k of 300ns static ram on a board I had to
>>that cost us $300 in the late 70's. The final code was about 1200 bytes,
>>or more of which were lookup tables for character fonts on 5x7 video
>>or timing constants. I also built the video it needed, a huge 120 line
>>high "8.8" display by hand. That took 6 bytes of DMA per video frame to
>you think that's retro? I am assembling a GENUINE replica of a
>MARK-8. 1 K of 1101 ram and a 8008 processor. Ok so maybe it
>has a little more ram BUT no S-100 bus. Just six cards
>wired together with bare bus wire so if you make a mistake
>it will take you at least 2 hours to get to it to fix it.
I looked at the 8008's instruction set, but came to the conclusion Intel
wasn't yet up to speed when they designed it. Too many, way too many, things
were on the missing list. There were only 2 things missing in the 1802's
closet, direct from memory to any register loads and stores, it all had to go
through the accumulator first, and no ready means of doing a subroutine call
or return, so those were in ordinary code, and you pointed r4 and r5 at the
call, and return routines respectively. Any of its 16, 16 bit registers
could be made into the program counter with a 1 byte command. Ditto for the
>And the programming is done with mechanical switches and LED
>lights to indicate register content and such. Keyboard optional !
>Now you are talking 120mm Howitzer. Making a mistake is not an option.
You got the picture, bright and clear.
>Oh and to make this more on topic later I will use an old 4k coco1 as a
>remote terminal :)
Yippers, I just knew it, I'm talking retro & cannon fire avoidance and
somebody has to do the "can you top this" routine. :-)
Sounds like fun Roy, keep us posted.
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Under a government which imprisons any unjustly, the true place for a
just man is also a prison.
-- Henry David Thoreau
More information about the Coco