[Coco] OS-9/68K raw disk access syntax

[Joel Ewy]

On 01/02/2016 09:42 AM, David Ladd wrote:
> Gene,
>
> ​​
> The MM/1 and the OS-9/68K uses 512byte sectors for its disk format.  The
> biggest oddity with the more current OS-9 is that it uses a starting sector
> #0 rather than #1 on each track.  The biggest thing is having a utility
> that knows this and is able to start with reading at sector #0.
> ​

The MM/1 may use 512 byte sectors for the hard drive, but by default, 
floppies are formatted with 256 byte sectors.

JCE

>
> On Fri, Jan 1, 2016 at 10:02 PM, Gene Heskett <gheskett at wdtv.com> wrote:
>
>> On Friday 01 January 2016 22:39:53 Joel Ewy wrote:
>>
>>> On 01/01/2016 07:34 PM, David Ladd wrote:
>>>> ​​
>>>> I might be wrong, but if memory serves me I think the MM/1's
>>>> OS-9/68K formatted floppies sectors per track starts at 0 rather
>>>> than 1 like some of the older floppy formats use to be.  So may have
>>>> to take that into account.  Sadly I can't verify this at this time
>>>> as my MM/1 is currently packed away.
>>>>
>>>> ...
>>> You're right about that, as I've discovered.  I think that's causing
>>> me a problem when trying to image the disks with 'dd' under LInux on a
>>> PC.
>>>
>>> JCE
>> Sadly, there are fdc chipsets built into some good motherboards that any
>> attempt to read or write a coco's 256 byte sector will take the machine
>> down, with the only recourse being the hardware reset button and a full
>> reboot done.
>>
>> This machine, with a nearly $300 when new Asus M2N-SLI Deluxe mother
>> board in it, is one such machine.
>>
>> Cheers, Gene Heskett
>> --
>> "There are four boxes to be used in defense of liberty:
>>   soap, ballot, jury, and ammo. Please use in that order."
>> -Ed Howdershelt (Author)
>> Genes Web page <http://geneslinuxbox.net:6309/gene>
>>
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