[Coco] NitrOS-9 ROM Pak ?

[Robert Gault]

Roger Taylor wrote:
> To Boisy,
> 
> Desoldering the ROMs from a CoCo motherboard is not for everybody.  I 
> think your NitrOS-9 ROM idea would boom if you found a way to do it from 
> a ROM Pak.
> 
> A 16K EPROM can autoboot in any controller or pak if the CoCo has 
> Extended BASIC.  Just prefix the ROM with the letters "DK" and execution 
> will start from $C002 as if it's a DOS.  I see no reason why you can't 
> at least pull off a 16K version.  I haven't burned and booted any 32K 
> ROM paks yet but I've done plenty of 16K paks.  If a 32K ROM Pak maps in 
> at $8000, then it should work almost as-is.  If a 32K ROM Pak maps in at 
> $C000 in 16K segments using GIME toggles, then it might be a little 
> tricky but definately not impossible to do a 32K version.
> 
> You might even be able to do this right now if you just assemble your 
> 16K NitrOS-9 ROM as relative code, then insert "DK" at the top of it.  
> If it's doable, I need to buy a copy.

You can't get both the kernel and the OS9Boot file in a DOS ROM even if 
16K. However, a second approach would be to just put the DOS routine in 
the ROM and nothing else. That would fit in an 8K ROM, would require a 
disk that contained both the kernel and OS9Boot file, and would be an 
OS-9 system only.
You just need to prevent the Coco3 ROMs from trashing your code by 
placing it where it won;t get patched.