[Coco] Nitros9 Boot Process

[Walter]

After reading the HDBDOS manual.

I figured I needed to set the OS9 offset for the HDBROM &H1938 to &H5A.  (5A0000 for VCCemudisk.vhd)

The ram value according to the manual is &HD938.  &HD939 & &HD93A are already 00 00.

So (poke &hD938,&h5A).

I have the VCCemudisk.vhd in DW device 0.

But dir 0 does not show me the expected autoexec/bas file in the first HBDDOS (DECB) floppy!
I get back DRIVE=0 FREE=0

Can I poke the OS9 offset on the fly to make this work?

Walter

-----Original Message-----
From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of Robert Gault
Sent: Wednesday, 16 January 2019 4:15 AM
To: CoCoList for Color Computer Enthusiasts
Subject: Re: [Coco] Nitros9 Boot Process

The VCCemudisk.vhd should have a boot disk in the Basic drive 255. Drive 253 or 254 will have tools 
for changing the boot "drive".

What is critical is that the BOOT module on the "floppy" is able to read whatever is used to boot 
into NitrOS-9 .vhd, hard drive, etc.
Now if you want to have your T34 in the OS-9 partition of your .vhd or hard drive, you can but it 
requires much more bookkeeping to make sure that OS-9 does not disturb your T34 sectors than if you 
have a Basic partition on your drive and the boot disk has a 35-T single sided format.

Regards DW-4, you could mount a .vhd in one of those drives. You could boot either from a Basic 
"drive" on the .vhd if you have a DW-4 BOOT module on the disk and the right driver/descriptors in 
the OS9Boot file. You could turn on HDBDOS Translation and have a boot disk on any DW-4 drive.

The point is that you can boot from essentially any device into a real or .vhd drive mounted on any 
device with the required BOOT and OS9Boot file.

You should be able to find what you need in the way of files and scripts in the NitrOS9 nightly 
builds by looking in the appropriate NITROS9 sub-directory.

Robert

Walter wrote:
><snip>
> 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



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