[Coco] Nitros9 Boot Process

Gene Heskett gheskett at shentel.net
Tue Jan 15 12:59:57 EST 2019


On Tuesday 15 January 2019 10:32:28 Walter wrote:

> Bill
>
> That makes sense.
>
> How is the boot organised on the nos96809l2v030300coco3_dw.dsk?
>
> It appears to be a single disk image with no floppys appended to the
> end of it.
>
> I think I get it!
>
> The VCCemudisk has floppys appended after 5A000 and the RGBDOS is
> aware of that offset!  And that was done to specifically boot from a
> floppy.
>
> If the ROM (RGBDOS, HDBDOS or whatever) is not aware of that offset
> then they will read from sector 0.
>
> Which is why I can boot Nitros9 from nos96809l2v030300coco3_dw.dsk
> with my HDB-DOS rom and without any floppy!
>
> Why wasn't this same approach also used for the VCCemudisk? Because
> then you wouldn't have any DECB floppies???
>
> I'm figuring that I could convert a VCCemudisk to boot without a
> floppy if I can free track 34 to perform  a successful os9gen.
>
> Walter
>
There are two ways to fix that Walter. You can either clear track34's 
bits in the allocation map using something like Chris Burks "bd" with 
the correct argument range, or you can use my kernal2dir utility which 
will make a roor directory entry for it, and then you can delete 
itdelete it. Either way, you have cleared the map bits and both os9gen 
and cobbler will then refresh the contents of track 34.

Kernal2dir is a runb program, get it from my site at 
<http://geneslinuxbox.net:6309/gene> I gotta get my sig fixed.
>
>

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>


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