[Coco] Preliminary Support for SDC in HDBDOS

[Robert Gault]

Brett Gordon wrote:
><snip>
> Am I correct in saying (at least on a CoCo3) there's no way to run the
> Top 8k in RAM ?  That means you wouldn't be able to run a 16k HDBDOS
> from anything but ROM ?  This might hurt any generalized HDB
> functionality we try to extend (like DW routines, or a new commodore
> style DIR that works with Louis's Cursed ).  Also, any of the existing
> utilities that dynamically load HDBDOS will break?
>
>

Any Coco can be set for 64K RAM with the exception of the I/O region at 
$FF00-$FFFF. If you mean that on a Coco3 Super Extended Basic exists from 
$E000-$FA0B, that is also true but not relevant. All you need do is switch 
between ROM/RAM as needed or on a Coco3 copy the extra 8K ROM into an MMU bank 
not currently in use. Basic does not use memory from $6E000-$6FFFF which  might 
work nicely for the extra 8K ROM.

I wrote for myself a version of Basic which hid a special BACKUP routine in the 
upper 8K of a 16K ROM.

Robert