[Coco] CoCo Questions

[Robert Gault]

Dan Olson wrote:

> So in short, Basic can only use 32k max for code and data, right?
Yes, as written.

> If I  understand correctly, the ROM is not copied to RAM by default, which 
> leads me to thing that the upper 32k of RAM is not being used by Basic. 
> This would be on a CoCo 1/2 if that makes a difference.
> 

That is right as far as it goes. The upper 32k on a Coco1 or 2 is the 
Basic ROM area while the lower 32K is RAM. If the Coco has 64k RAM 
installed then it could be used as follows.

It is perfectly legal to write an ml program to switch the system to all 
RAM mode and make use of the upper 32K of memory assuming 64k RAM is 
installed. However, Basic can't make use of this area. If you want to 
use the extra 32k for a Basic program, you would need to write some ml 
routines that access this area of memory, transfer data back and forth 
between low and high RAM, and then switch back to mixed RAM/ROM mode 
before returning control to Basic.