[Coco] Booting Nitros9 from the VCCemudisk.vhd on a Real CoCo III

[Walter Zambotti]

Thought I'd note the process of how I got my CoCo III to boot Nitros9 on a
real CoCo III

 

Equipment:

 

CoCo III (512K)

1 x FD Controller & drive (not required)

1 x MPI (not required)

1 x HDB-DOS (mine is in a miniFLASH) (OS9 Offset $000000)

1 x DriveWire 4 server (+ serial cable)

1 x VCCemudisk.vhd

1 x 630 sector virtual floppy on DW server (NOS9_BOOT.OS9) cleanly formatted
for OS9

1 x Nitros9 DW boot floppy (
<https://nitros9.sourceforge.io/snapshot/NOS9_6809_L2_v030300_coco3_dw.dsk>
NOS9_6809_L2_v030300_coco3_dw.dsk)

 

Procedure

 

Mount NOS9_6809_L2_v030300_coco3_dw.dsk in DW device 0

Mount VCCemudisk.vhd in DW device 1

Mount VCCemudisk.vhd (with offset 529290, size 630) in DW device 2 (HDBDOS
boot floppy)

Mount NOS9_BOOT.OS9 in DW device 3

 

Boot CoCo III to Nitros9. (DOS)

If the NOS9_BOOT.OS9 is not formatted then format it: 

format /x3 "NOS9 Boot" '35'

OS9GEN the new boot floppy: 

os9gen /x3

/dd/OS9Boot

 

Copy the contents of the HDBDOS boot floppy to the new boot floppy:

Chd /x3

Dsave /x2 | shell (this will skip the OS9Boot file)

 

Backup the new floppy to the HDBDOS floppy:

Chd /dd

Backup /x3 /x2 #32k

 

Restart the CoCo

Dismount all the devices in the DriveWire server

Remount VCCemudisk.vhd in DW device 0

 

Point HDB-DOS at floppy 0 of VCCemudisk.vhd:

Poke &HD938,&H05

Poke &HD939,&HA0

Poke &hD93A,0 ! shouldn't be necessary

 

Dir should now see the autoexec/bas on the first HDBDOS floppy

 

Boot away:

 

DOS

 

The EMUdisk quick select menu should popup and from there you can select the
option to boot to OS9.

 

It was really nice after all these years to see my CoCo III boot up to the
same software that I have been
using for years on VCC!

 

It would be nice if HDBDOS had a set offset command so I didn't need to
poke!

 

Walter