[Coco] CoCo 3 patch question

[Robert Gault]

Roger Taylor wrote:
> Does anyone know if the CoCo patches the Disk ROM if it's available?
> 
As others have said, yes.

> I'm not sure what OTHER bytes are 
> altered by the CoCo 3 patch routines.  
The best way to study this is using the "Super Extended Basic 
Unravelled" book. The Coco3 patch routines start at $C000. Part of what 
happens is that the code looks for DK at $C000 in the DOS ROM. If found, 
the external ROM is moved into RAM. Then the code looks for clues to 
DOS1.0 or 1.1 and proceeds accordingly.

>This leads me to ask yet another 
> question... how does the CoCo 3 (if it's patching Disk BASIC) deal with 
> the other DOS brands?
> 

The code can't and doesn't take into account third party DOS 
modifications. However, there is so little patching done that it is not 
hard to avoid these areas.