[Coco] [Color Computer] Create NitrOS9 L1 boot disk for Dragon with FD-502?

[Boisy Pitre]

On Sep 24, 2006, at 4:45 AM, drag0n1969 wrote:

> I need help creating a NitrOS9 Level 1 boot disk for my unique
> configuration: Tano Dragon with a Tandy FD-502 disk controller.
>
> I have replaced the FD-502's EPROM with a special version of Dragon
> SuperDOS, modified by Phill Harvey Smith to work with the Tandy
> controller hardware. This works perfectly under basic.

Chen,

I have done exactly what you are attempting to do.  It IS possible to  
boot NitrOS-9 Level 1 on a Tano using a Tandy-compatible controller.

> Creating a NitrOS9 boot disk is a problem, since the Dragon Dos
> expects the boot sector on track 0 (from sector 3), and not track 34
> as on the CoCo (though both of them load the boot sector to same
> memory address at $2600)
>
> Am I correct that my boot disk should simply be a Dragon NitrOS9
> boot disk with the modules BOOT and RB1773 from the CoCo (replacing
> the dragon's BOOT and DDISK)?

Yes, that is correct.  When creating the boot, you need to use the  
dragon-compatible os9gen which will put the kernel track at track 0,  
sector 3.

> I have tried using MESS to generate this bootdisk – with no success
> whatsoever.
>
> I also tried generating a CoCo bootdisk, replacing the VTIO and
> COVDG – to get a proper Dragon keyboard. Didn't work either…
>
> I'm starting to think that the BOOT module contains info about both
> the physical boot sector location, and the controller hardware: thus
> if I use the Coco boot module it finds the hardware, but looks for
> the boot module in sector 34 rather than sector 0.

The boot module doesn't know about the location of the kernel track  
on the boot disk; its only concern is to seek to LSN0, read that  
sector, determine the location of the bootfile, then read that  
bootfile into memory.

> If this is a correct, I guess the Coco boot module needs to be
> patched to read sector 0?

No, because of my comments above.

> I have also tried to "force" the dragon to boot a CoCo bootdisk,
> using a small program on the Dragon to read sector 34 from the CoCo
> boot disk, poke it into address 9728 ($2600)  onwards, and EXEC
> 9730. Doesn't seem to work either…
>
> I have been struggling with this for quite a while now, trying
> numerous combinations. Any help would be greatly appreciated…

I can tell you that my boot disk creation was done using ToolShed and  
the NitrOS-9 package installed on my Mac.  The resulting disk image  
was copied to a real floppy disk under Linux and booted fine on the  
Tano Dragon with the Disto SC-I controller I have connected to it.

You're attempting to do this under MESS with a version of NitrOS-9?   
Perhaps a detailed listing of the steps and commands you use would  
help in debugging this.

Boisy