[Coco] Re: Run NitrOS-9 on the JVC/Collyer Coco3 emulator

[Robert Gault]

PART II

Below is PART I for running NitrOS-9 double sided drive images with the 
JVC emulator through the use of the os9boot.mor replacement for 
coco3.rom. However, that would prevent the use of Disk Basic or RGBDOS 
with the JVC emulator. Once you have booted into NitrOS-9 by the method 
of PART I, here is how you can created an image that will boot using the 
normal coco3.rom thus permitting the use of a normal disk.rom.

Boot NitrOS-9 from the double sided image and run dmode to list the 
specs of /d0. Use dmode to change /d1 so that the typ entries are the 
same, sid=1 and cyl is double the value for /d0. Then using [F2], create 
a new entry for drive 1.

Now enter "format /d1" (without the quotes) and when finished run 
cobbler on /d1. This will finish creating a single sided image the same 
size as /d0 but with the os9boot track on LSN $264 (track 34) instead of 
LSN $4C8 (track 68). You can verify this by using dEd. Then make sure 
you are in the root directory of /d0 and enter "dsave -s56 /d1 ! shell". 
This will copy everything from /d0 to /d1.

Now that you have made a copy of your boot disk in single sided format, 
replace the os9boot.mor version of coco3.rom with the original 
coco3.rom. This will once more make Disk Basic or RGBDOS available. 
However, you will now be able to use the DOS command and boot your new 
NitrOS-9 image.

Robert Gault wrote:
> Getting the NitrOS-9 images onto a real Coco system can be a problem and 
> some people may want to stop on a PC with an emulator. The most 
> universal emulator that can run all versions of NitrOS-9 is MESS. The 
> simplest way to get the images to work with MESS is to change the 
> extension from .dsk to .os9.
> 
> The latest version of the Vavasour / Collyer emulator Coco3 6309 v1.91B 
> can also run NitrOS-9 with a little help. The most powerful version of 
> NitrOS-9 is the Level-2 6309 and the full program is distributed on an 
> 80 track double sided disk image. So let's use this as an example.
> 
> The Collyer program can be obtained from RTSI
> ftp://www.rtsi.com/RSDOS/incoming/  in the johncollyer_website.zip file 
> as ver19.zip. Os9boot.mor (a necessary file) can be obtained at
> http://www.vavasour.ca/jeff/trs80.html#coco3 . NitrOS-9 can be obtained 
> from http://www.nitros9.org .
> 
> Step 1: Rename os9boot.mor to coco3.rom and install it with the 
> JVC/Collyer emulator. This rom will boot directly to OS-9 using the disk 
> image installed on drive0. However, one byte of the file must be changed 
> with an editor so it can find the boot track on a double sided image. 
> Step 2: Use a raw file editor and look for the patter $15 CC 22 01 ED 
> (near the start of the file) and change the $22 to $44. Now we need to 
> change the NitrOS-9 .dsk image to indicate that the disk is single sided 
> instead of double sided.
> Step 3: Use a raw file editor to change the 17th byte of the .dsk image 
> from $03 to $02. This will tell OS-9 the image is single sided.
> 
> Now you can start the emulator and NitrOS-9 will automatically boot.
> 
> There may be one final problem with the emulator as it needs DOS not 
> Windows to run NitrOS-9 correctly. Not all Windows system have a DOS 
> mode. You may need to run emulation from a boot floppy on such systems.
>