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Re: Crosspost: Did the cpu influence the display?



On Mon, 26 Dec 2005, The Wizard of Oz wrote:

There is something nobody has talked about yet. Possibly because it might
not have made it out of Winnipeg. M$ made a CP/M card for the Apple//. It
worked in my ][+, sort of worked with my //e clone, and wouldn't work in
my GS.

Try running the GS in 1 MHz mode.

It was intended to be a text only display using the Apple as a
display unit. I think someone locally wrote a unit for Turbo Pascal which
used the Apples memory to display HGR graphics. I took a look at the calls
and figured out how the author did it. The M$ card had a special routine
which allowed the programmer to directly access the Apples soft switches.
The RAM wasn't on the CP/M card. The card just rearranged the available
memory from the Apple and had a limited amount of RAM and I guess ROM to
replace what was used by the Apple. The memory was allocated and the unit
was a series of routines which built on the plot of a single point. It
still displayed graphics in colour.

There is a version of MBASIC that supports the graphics commands from Applesoft. I've used it on real hardware (knockoff, not M$ brand). Doesn't really work well on the //e because CP/M insists on running in 80-column mode.

-uso.