[Coco] Preliminary Support for SDC in HDBDOS

[Brett Gordon]

This weekend I was able to hack in some preliminary support for
CoCoSDC into HDBDOS.   This will allow you to treat a SDC mounted hard
drive image in the same manner as the other devices (IDE,SCSI,DW,
etc...)

I have replaced the only the low-level DSKCON drivers, so HDB can
access the two logical drives. However, HDBDOS cannot do all the fancy
stuff (yet) - mount disk images, list the SD directory.  In other
words, you will probably have to have a config.ini on your SD card to
make SDC auto-mount images.

I have shared three files here:   http://sites.google.com/site/cocoboot2/down

hdbsdccc3.dsk :  cocoboot disk that autoloads the new HDB (coco3)
hdbsdccc2.dsk:   save as above for the CoCo2
hdbsdc.rom:        a new ROM image (set for partition offset 0x000000 )

There's two ways to try it:

1. Burn (flash) the ROM to your device, and boot.  The same directory
has a SDC flashing utility.

2. Use the above cocoboot disk to use HDBSDC in RAM.  If the cocoboot
disk fail to boot properly, its probably because you have an MPI, or a
strange configuration.. no worries: CoCoBoot contains a menu-driven
setup program to help you tailor the boot to different setups. (Yes,
it can change your HDB partition offset)

This is all experimental (but tested).  Shortly, I'll ask for a code
review of my changes to HDBDOS, and maybe they will get pushed to the
repo.

If you need any help, email me.

-- 
Brett M. Gordon,
beretta42 at gmail.com