[Coco] Help with Nitros9 on SDC?

Don Barber don at dgb3.net
Sat Apr 10 09:13:06 EDT 2021

Jeff, thanks so much, this is absolutely it.

So it comes down to my ignorance of how OS9 does drivers and device 
descriptors work...I didn't even think of this as a possibility. Will do 
further research on how descriptors are assigned and how to list them.



On 4/10/21 12:00 AM, Jeff Teunissen wrote:
> I'm 99% sure that your problem is caused by the use of the /D0 and /D1
> device descriptors.
> The CoCoSDC normally emulates a floppy controller, and that works
> great for floppy-sized images, but not _totally_ for hard drive sized
> ones like the ones we use for NitrOS-9.
> Now, the CoCoSDC boot file for NitrOS-9 3.3.0 includes two different
> disk drivers to operate the SDC: there's the classic "rb1773" driver,
> which old OS-9 called "CC3Disk" and talks to the SDC like it's a
> floppy controller (and has devices /D0, /D1, /D2, and /D3), and
> there's the "llcocosdc" driver, which talks to the SDC like it's a
> hard drive and has devices /SD0 and /SD1.
> If you check the number of cylinders, sides, sectors, etc. of the /D0
> and /D1 devices, you will probably find that they're set up for
> 80-track 720K floppy disk drives, or possibly 360K drives, while the
> /SD0 and /SD1 devices are set up for disks with thousands of
> cylinders.
> If you never actually use a real floppy controller, you can safely
> remove the rb1773, d0, d1, d2, and d3 modules from your boot file to
> save a bit of memory, or leave them in and just stop using them.
> Either way, you want to use /SD0 and /SD1 instead.
> <snip>

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