[Coco] OS9 68K, MM/1 software and questions

[Joel Ewy]

On 12/30/2015 10:03 PM, Zippster wrote:
> ...
> My plan was to replicate the older IO and backplane, as that’s what I have available to refer to.
> I need to gain a better understanding of the differences between them.  Was there only one CPU PCB version?
>
> It sounds like there was 3 versions of the I/O, and 2 of the Minibus?
AFIK there was only 1 CPU board, 3 versions of I/O, and 2 backplane.  
The first backplane had no memory.  It was just a passive backplane.  
The version 2 (I think) I/O board I have in my MM/1 could have 2 1M 
SIMMs.  The second backplane had the 8M memory interface, and the 
version 3 I/O board had no SIMM sockets.  You can use the 8M (V2.0) 
Minibus board with the Version 2 I/O board if you configure the I/O 
board for no RAM.  That's how my machine is set up.

JCE

> - Ed
>