[Coco] CoCo Questions

[Robert Gault]

PaulH96636 at aol.com wrote:
> In a message dated 10/28/2006 12:23:19 P.M. Eastern Daylight Time,  
> cappy2112 at gmail.com writes:
> 
> I'm  pretty sure I had this when in my Coco time, but I thought it was a 
> cartridge  and came with a plastic keyboard overlay.
> There were quite a few of these  "Basic Enhancer" programs. You would press 
> one key and it would enter Basic  Keywords for you. 
> *************
> No, Key-264K is quite different from the description above.  To check  out 
> the specs, look
> for advertising by Key Color Software in some of the early-to-mid-1980s  
> Rainbow magazines,
> such as the August 1985 Rainbow games issue, page 156.   Newer  issues likely 
> would no
> longer have the ads because of the rumored upcoming Coco-3 with its 128kb  
> ram, upgradable.  
>  
> Key-264K gives you two banks of 32k ram (in a 64k machine) which can  operate
> independently of each other, or be interactive, in RS basic, with some  
> additional commands.
>  -ph
> 

There are other programs that did more or less the same thing. The 
principle is simple, use the RAM/ROM mode and swap between two pages of 
RAM at $0000-$7FFF. The SAM switch for this is $FFD4-$FFD5. The Coco3 
does not emulate this function.

Making interactive communication between the two pages would be tricky 
because any changes made to RAM in one page would be lost after swapping 
to the second page. You would almost be forced to store common data in a 
disk file which would be written to before a page swap and read 
immediately after one.