Re: Mystery Board

[supertimer@aol.com (Supertimer)]

david@uow.edu.au (David Wilson) wrote:

>Jeff Lemke <lemke@terra.cira.colostate.edu> writes:
>
>>I've come across a board by "Stellation Two".
>>
>>Anybody know what this board is?
>
>Yes - I have one as well. It is a 6809 co-processor card for the Apple //.
>Just like the z80 SoftCard, it allows you to run code written for a different
>CPU. Unlike the z80 SoftCard, both CPUs run at the same time (well almost -
>about 1 in 5 cycles (when the 6809 does not need the bus) the 6502 gets to
>run for a cycle).
>
>3)	OS/9 Operating system. This came with a daughterboard
>	that had a switch and a small ROM (32x4 bits?) that remapped
>	the address space of the Apple // so that the screen and zero
>	pages were not stomped on by OS/9 programs. The daughter board
>	replaced the LS367 buffer nearest the edge connector.

For those who do not know, OS/9 is an old operating system that ran
on several systems including the Tandy Color Computer 3 (CoCo3).
I supports pre-emptive multitasking.