[Coco] DW3DOS ROM not loading NitrOS9 correctly

[Chad H]

Ok Robert, I'm not trying to convert a .BIN to a .ROM in this situation, I
am fully aware of the difference between the two.  You are referring to
another problem where I was trying to figure out how to get a .BIN converted
so that I could flash it into a EPROM.  This is NOT what I'm trying to do
with the DriveWire ROM.  I just flashed the dw3dos_dsk_cc2.rom into a 2764,
simple and easy, did it many many times.  BTW,  Merry Christymas!!

To cover the bases, I did go back and erase the EPROM and re-flash it with
that same ROM.  It did the same thing.  I tried loading the .BIN version as
you suggested with LOADM and it DID boot successfully the .VHD in DriveWire
slot#0.  So what's the difference?  I removed the EPROM from my CoCoEPROMpak
and put it in another EPROMpak board (Mark's CoCoFlash, see
http://members.iinet.net.au/~msmcdoug/coco/coco.htm)  and it did the same
behavior.  Finally, I removed the EPROM once more, placed it into the FD-502
controller, and tried again..  Well guess what, this time it WORKED!!  So
what's different about it being in the FD-502 controller?  Is the ROM
somehow looking for hardware differences of the controller?  That's the only
thing I can think of.  I know that the EPROM pak boards work perfectly and
that I know how to flash a .ROM to a EPROM and that the EPROM is good.

-----Original Message-----
From: coco-bounces at maltedmedia.com [mailto:coco-bounces at maltedmedia.com] On
Behalf Of Robert Gault
Sent: Wednesday, December 25, 2013 9:13 AM
To: CoCoList for Color Computer Enthusiasts
Subject: Re: [Coco] DW3DOS ROM not loading NitrOS9 correctly

Chad H wrote:
> p.s.  Yes the NitrOSO .vhd on the server drive 0 is good.  Its what i have
been going into all along by DOS command or a special floppy disk I made for
my modified drivewire rom in my 502 controller.  That ROM has 'DRIVE OFF' by
default at bootup so I can AUTOEXEC real floppies.  I have a floppy I made
bootable in NitrOS9/DW.  Using this disk with the DOS command, it boots from
the floppy for the first part of the boot process (till the screen goes
blank with 'NITROS9 BOOT' in the center) at which time it finishes the boot
from reading the DriveWire server's Disk 0.   So that image works in various
situations... just not from the DW3DOS ROM I pulled from the Cloud 9 ZIP.
>
> Sent from my Transformer Infinity
>
> Chad H <chadbh74 at hotmail.com> wrote:
>
> The one I tried was "dw3dos_dsk_cc2.rom" from the archive on the Cloud 
> 9 site.  When booting that in EPROM, it does access the DriveWire 
> server and reads a bunch of sectors and displays "NITROS9 BOOT" on the 
> screen.  If I take the server offline before booting the ROM, it very 
> quickly goes to "BOOT FAILED" on the screen.
>

OK, I just compiled DWDOS and have looked at the results but not yet tested
the code on a real Coco, of any model.

You chose the correct ROM image to burn into an EPROM but the first thing
you should have done is tried the LOADM version dw3doscc2.bin. This version
will load code into memory at $2400 and execute from that address.

So, you need to tell us exactly what happens when you use the LOADM version,
or if you don't have a disk system, what happens if you use the tape version
(CLOADM) dw3doscc2.wav .
If either (C)LOADM version fails, then there is a problem with the code or
the server settings. If either of these works, there is a problem with the
manner in which you created your EPROM.

You have asked frequently about converting .bin to .rom images. I presume
the real question is how to generate an EPROM.
The dw3dos_dsk_cc2.rom is a pure ROM image and can't be used with LOADM. It
must be transferred to your EPROM programmer as is, to be burnt from $0000
to $1DFF on your EPROM.
I use the Disto MPROM Adapter with a Disto SCII disk controller. This device
has no provision for acquiring data directly and the image must be a LOADM
.bin file. In this case, the LOADM header/instructions place the file at
$3000-$4FFF to be copied by the MPROM unit to the EPROM. So if I wanted to
save a disk ROM for use with the Disto unit, the commands might be:
SAVEM"DISKROM",&HC000,&HDFFF,&HA027
LOADM"DISKROM",&H7000
The above commands would offset load the ROM image to $3000
($C000+$7000=$13000) for the Disto.

Regarding the dw3dos_dsk_cc2.rom image, there is some code in it I've not
seen in a Coco ROM.
sta $FFDA
sta $FFDD
This code will tell the SAM how much memory is present in the Coco. However,
I'm under the impression that this info was hardwired with jumpers and these
two bytes were not used. I've no idea what will happen if you POKE these
bytes.

Robert


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