[Coco] RGBDOS for the JC/JV Emulator

[Robert Gault]

John Donaldson wrote:

>  I made a new  6809 emulator directory and installed RGBDOS. It  
> installed just fine and
> everything looks good. I did notice one thing. I unzipped and copyed the 
> 6809 NitrOS9 DSK's
> to the new direcotry. Set the emulator so that disk0 pointed the the 
> DS40_1.DSK and disk1
> pointed to the DS40_2.DSK. Typed "DOS0" and got a OK back. NitrOS9 disk 
> did not
> boot.
>   I then copyed all the ROM files to a backup direcotry. copied my OS9 
> boot ROM,
> COCO3.ROM from another directory that I use to boot 6809 NitrOS9. I made 
> sure the
> 40Track NitrOS9 disks were in drive 0 and 1, Restarted the emulator and 
> NitrOS9 booted
> just fine. this rom has been patched to look first at track 68 if a 80 
> track DSK is present or
> Track 34 if it is a 35/40 track DSK.
>    I then saved this COCO3.ROM and used OS9BOOT.MOR and made a copy of it
> and called it COCO3.ROM. I reset the emulator and when it executed,  OS9 
> failed to boot.
>     I then copied the two NitrOS9 files over tot he emulator directory 
> that I run 6809 Basic
> from. I again set the DSK's to drive 0 and 1. Started the emulator, 
> typed "DOS" and all I
> got was a "OK". NitrOS9 did not boot.
>    When I did get the DSK's to boot, I did a DIR on /d1 and got NITROS9, 
> which is
> correct. I then typed DIR /D1 NITROS9 and got /D1/NITROS9/6809L2, which 
> again is
> correct. I then typed DIR /D1/NITROS9/6809L2 and got /D1/NITROS9.   Just 
> to make
> sure that I did not have a bad copy, I used my MSDOS machine and went 
> back to the
> NitrOS9 Project web site and redownloaded the files all over again. Got 
> the same results to
> the various tests. The 80 Track DSK works fine after I reset the offset 
> from 07 to 06.
>   This brings me to a question, do I need to reset the 40 track DSK 
> offset from 03 to 02??
> 
> John Donaldson
> 
> 
> 
You may need to add the correct two byte header to all your .dsk images 
for the JC/JV emulator to function correctly. That is a much better 
approach than changing the OS-9 boot module.

I believe your main problem is that the emulator is not correctly 
interpreting the .dsk structure because most/all of the NitrOS-9 release 
disks are not multiples of 35TDSided or 40TDSided. JC/JV will get 
confused under these conditions without the JV header.