[Coco] Determining OS-9 Floppy Type

Joel Ewy jcewy at swbell.net
Sun May 27 09:02:36 EDT 2007


Bob Devries wrote:
> Gene,
> I believe that Andrew is trying to tdo this on a PeeCee, so the dmode
> command ain't gonna help him much.
>
Actually, here's what Andrew says:

"Whether the method uses DECB, OS-9, or DOS, it doesn't matter. However,
I don't have access to a Windows machine with a 5.25 floppy drive, so
that method is out."

JCE
> -- 
> Regards, Bob Devries, Dalby, Queensland, Australia
>
> Isaiah 50:4 The sovereign Lord has given me
> the capacity to be his spokesman,
> so that I know how to help the weary.
>
> website: http://www.home.gil.com.au/~bdevasl
> my blog: http://bdevries.invigorated.org/
>
> ----- Original Message ----- From: "Gene Heskett"
> <gene.heskett at verizon.net>
> To: <coco at maltedmedia.com>
> Cc: "Andrew" <keeper63 at cox.net>
> Sent: Sunday, May 27, 2007 2:12 PM
> Subject: Re: [Coco] Determining OS-9 Floppy Type
>
>
>> On Saturday 26 May 2007, Andrew wrote:
>>> As you all know, I am doing a floppy disk conversion project for Carey,
>>> to rescue a bunch of data from some old floppies, and convert it into
>>> images which can be read under emulation. I have already completed the
>>> DECB subset of floppies, and I am beginning to tackle the OS-9 subset.
>>>
>>> However, I am running into a snag. When I worked on the DECB subset, I
>>> was able to determine what kind of disks the OS-9 floppy sides were
>>> (some of the floppies were "mixed" - one side being DECB, the other
>>> OS-9) by inference:
>>>
>>> Since under OS-9 there are only 35 track SSDD device descriptors and 40
>>> track DSDD descriptors (but no 40 track SSDD descriptors), if there was
>>> readable OS-9 data on one side of a floppy and the other was DECB
>>> formatted (and there were two index holes punched in the floppy
>>> jacket),
>>> then it could only be a 35 track SSDD floppy side.
>>>
>>> However, I can't make that inference now since a 35 track SSDD floppy
>>> (with a single index hole) looks the same physically as a 40 track DSDD
>>> floppy (which also has a single index hole). Unless it is labeled as a
>>> certain format, I am not sure how to tell which is which.
>>>
>>> Can anyone tell me what the best way of determining whether an OS-9
>>> formatted floppy is a 35 track SSDD floppy or a 40 track DSDD floppy?
>>> Whether the method uses DECB, OS-9, or DOS, it doesn't matter. However,
>>> I don't have access to a Windows machine with a 5.25 floppy drive, so
>>> that method is out.
>>>
>>> I need to know this information so I can make a proper backup and
>>> recovery image of the floppy (btw - what would be the best way for
>>> me to
>>> create a DSK image of a 40 track DSDD OS-9 floppy under DOS?). Is there
>>> a way to take an image with each side using RETRIEVE.EXE and then
>>> combining them somehow? Or, is there something like RETRIEVE.EXE, that
>>> runs on DOS, that will do this?
>>>
>>> Or - could I run a program under DECB in the emulator that took each
>>> side image and then directly wrote it to a third image using DSKI$ and
>>> DSKO$? Or perhaps in a similar manner use OS-9 on the emulator to pull
>>> and combine each image?
>>>
>>> Hmm - this conversion effort for the OS-9 floppies has gotten hairy
>>> quickly. Any and all answers will be appreciated - I don't plan on
>>> doing
>>> anything until I have a working answer from someone(s) out there, or no
>>> answer is forthcoming and I have to cobble something together myself.
>>>
>>
>> Andrew, for os9 there is a very handy utility, called 'dmode'.  With
>> it you
>> can adjust a spare descriptor (/d1?) in your bootfile so that it can
>> read
>> virtually any format the drive itself can handle.
>>
>> The arguments you want are 'sid' and 'cyl' which stands for the
>> number of
>> sides, and the cylinders/tracks the disk might have.  Note that the
>> value
>> for 'cyl' is stated in hexidecimal, so a 40 track disk is 28 in hex,
>> and an
>> 80 track disk is 50 hex.
>>
>>> Thank you in advance...
>>>
>>> -- Andrew L. Ayers
>>>    Glendale, Arizona
>>>
>>> -- 
>>> Coco mailing list
>>> Coco at maltedmedia.com
>>> http://five.pairlist.net/mailman/listinfo/coco
>>
>>
>>
>> -- 
>> Cheers, Gene
>> "There are four boxes to be used in defense of liberty:
>> soap, ballot, jury, and ammo. Please use in that order."
>> -Ed Howdershelt (Author)
>> system-independent, adj.:
>> Works equally poorly on all systems.
>>
>> -- 
>> Coco mailing list
>> Coco at maltedmedia.com
>> http://five.pairlist.net/mailman/listinfo/coco 
>
>
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>




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