[Coco] OS-9 Level I v2.0 hard disk image how-to?

[rick ulland]

Finish typing before send next time...

I don't think the physical format matters, but the encoding sure does. 
What are the old RS system. The devpak drivers have 0% docs. It does 
'something' when you give it tracks and cyls... the controller is in the 
drive. Very IDE ish.  Are they um, emulated in an emulator?

-ricku

On 10/8/2022 6:48 PM, rick ulland wrote:
> Good question with many levels. Physical CoCo, a descriptor identifies 
> tracks/heads/etc, and the driver applies those settings to 'an 
> controller'. If you have an OS9 driver, and you are not going to 
> attach a physical disk, 'dmode' any legal descriptor settings and 
> nobody cares.  As a really old guy, no idea how to format a virtual 
> disk for the hardware that isn't there, but I hope this starts a convo.
>
> -ricku
>
> CoNect
>
> On 10/8/2022 4:34 PM, Robert "Exile In Paradise" Murphey via Coco wrote:
>> If I wanted to emulate a CoCo 2 with the 15 or 35MB Tandy hard disks,
>> how could I do it?
>>
>> The OS9 Level 1 v2.0 addendum says the Tandy hard disks are:
>>
>> 15MB uses 6 heads, 306 cylinders, 345 tracks per inch, 32 sectors per
>> track and 128 pre-comp.
>>
>> 35MB uses 8 heads, 512 cylinders, 512 tracks per inch, 34 sectors per
>> track and 256 pre-comp.
>>
>> The two options I know of up front to format a disk image are:
>> Toolshed os9 tool
>> MAME imgtool
>>
>> MAME imgtool does not let me specify enough heads or cylinders, and my
>> suspicious is that the field is 8-bit anyway so the numbers given won't
>> work.
>>
>> os9 let's me create an image with the same total logical sectors, but
>> the geometry doesn't match up and I don't know if that would stump the
>> driver or if I need to create a different device descripter.
>>
>> So, I am reaching out to see if anyone has any tips on how to simulate
>> the original 15M or 35M hard disk on OS9 Level I v2.0 for a CoCo 2...
>> using emulators or hardware with the CoCoSDC attached.
>>