[Coco] Nitros9 Boot Process

[Walter]

I did it

Poke &hD938,&h5
Poke &hD939,&hA0
Poke &hD93A,0

Dir 0 

Success

DOS

The emudisk quick selection menu popped up!

Press 5 to boot to OS9.

Bingo!  Success

/dd is now /x0

Of course I had to backup my 630 sector Nitros9 DW boot floppy to disk 255 of the VCCemudisk.vhd.

I did this by mounting just the last 630 sector of the vhd in DW server and then using OS9 backup to backup my boot floppy to that

So /x1 has the last 630 sectors (disk 255) of the vhd mounted
And /x2 has by newly os9gen'd 630 sector Nitros9 DW floppy mounted

Backup /x2 /x1

All done

I can now boot VCCemu disks directly from my CoCo!!!

Of course I don’t want to poke the os9 offset every time I cold start but is useful to understand the process.

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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