[Coco] NitrOS-9 ROM Pak ?

[Roger Taylor]

At 03:06 PM 3/29/2009, you wrote:
>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.

I thought Boisy's FAQ talks about using a 16K ROM (for a CoCo 1/2?).
What about a 32K ROM.  I've never burned any to see if they map in at 
$8000 or $C000 in two banks.  If they map in at $8000, it's the same 
exact thing as desoldering the CoCo 3 BASIC ROM set chip if you can 
just map the ROM in right or copy it down into the underlying RAM.

The desolder job to a CoCo 3 motherboard is highly unlikely to catch 
on.  A ROM Pak with NitrOS-9 on it would be something I'd buy right 
now this minute.  The ROM could fetch anything else from the floppy 
disk sitting in the DRIVE 0.


>  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.

it sounds you're describing a regular booting OS-9 disk but using a 
patched DOS that JMPs to the "DOS" command on powerup, like $C002 JMP 
DOS.  I don't want to boot from floppy.


>You just need to prevent the Coco3 ROMs from trashing your code by 
>placing it where it won;t get patched.

-- 
Roger Taylor

http://www.wordofthedayonline.com