[Coco] CoCo Questions

[Robert Gault]

Phill Harvey-Smith wrote:
><snip>
> 
> Well You could have a small copying routine in ram that would disable
> interrupts, and then switch to map type 1 whilst copying, as then the 
> other 32K would appear in the 32K-64K region, and could therefore be 
> accessed at the same time, I would not have thought that this would have 
> been too hard to arrange.
> 
> Cheers.
> 
> Phill.
> 

That won't work if you are using page swapping because the only RAM 
available is the lower 32K and your ml program will get swapped out 
along with any data it stored.

If you use type instead of page swapping, then you flip between 32K RAM 
+ 32K ROM and 64K RAM. In this case you can have your swapping routine 
and data in low RAM accessing information and/or a second program in the 
upper 32K of RAM. For this to run two separate Basic Programs, you would 
need to copy all of the 32K in upper RAM to lower RAM except where your 
routine and communication data are located. That is a lot of overhead 
for something practical.

In my opinion, programs of this type only became practical on the Coco3 
where the swapping routines could be in constant DRAM and there was 512K 
RAM to play with.