Some said they have CDOS and Cromemco disks
cctalk at randy482.com
Sat Apr 16 00:04:20 CDT 2005
From: "Dave Dunfield" <dave04a at dunfield.com>
Sent: Friday, April 15, 2005 11:33 PM
>I played with the serial <> RDOS transfer a little bit more
> this evening.
> I was able to transfer an image of CDOS + INIT into the machine
> and start it up directly from memory - however in order to make
> sure that this is doable on a Cromemco bank switched memory card,
> I have to keep it within 32k ... I discovered that CDOS won't INIT
> a DS/DD disk when it's gen'd for 32k (I get a weird error about a
> non-existant drive 'h') ... It works fine if gen'd for 48k or 64k.
> It will however INIT a SS/SD disk when it's gen'd for 32k ... so
> it's going to be a bit of a multi-step process. First, you download
> CDOS+INIT to memory and INIT a SS/SD disk - then you transfer a
> SS/SD disk image with 48k gen'd CDOS and INIT - this will let you
> INIT any type of disk. Once you INIT a DS/DD disk, then you can
> transfer the full CDOS and Cromix images.
> I'm doing this with 5.25" drives - I assume most people will be
> able to dig up a 5.25" drive to bootstrap, even if their machine
> as 8" drives - I'm genning the CDOS to have Drives A=Small B=Large
> C=Small and D=Large - that way you should be able to INIT the
> right type of drive on a system with either two small or two
> large drives.
> dave04a (at) Dave Dunfield
> dunfield (dot) Firmware development services & tools: www.dunfield.com
> com Collector of vintage computing equipment:
That's great! I can make a few suggestions:
I can send you older CDOS's that should be more memory lean. Some older
CDOS's had normal SA800 support via undocumented drive type 'X' even though
CDOSGEN only references 'S'mall & 'L'arge.
If you have 64K of RAM RDOS can be copied to RAM giving you access to the
full 64K allowing Larger CDOS's: Using a random address such as 1000H:
Just use the substitute memory command to enter the above code (hex) and do
a g 1000 (a return returns to RDOS). You are now running RDOS out of RAM.
You can have one 32K CDOS and maybe a 64K CDOS to transfer. BTW you never
have to use 8080 only opcodes since RDOS & CDOS only run on Z80's. Also the
above code can go in any free space and is not address dependent.
Remind people of my favorite mantra: 3.5" drives with DD media will be
happy to act as 5.25" DD drives.
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