Re: CBM-900 floppy disk format/encoding

Well, I still think it's highly unlikely that the CBM-900 would use totally 
incompatible 100TPI disk drives/format, but I suppose anything is possible.

If the Kryoflux can read the flux that would seem to suggest that you're on 
the right tracks ;-) and it just can't make sense of the actual layout.

But good luck!

mike

----- Original Message ----- 
From: "Uffe Jakobsen" <uffe@uffe.org>
To: <cbm-hackers@musoftware.de>
Sent: Saturday, October 22, 2011 7:54 PM
Subject: Re: CBM-900 floppy disk format/encoding


>
>
> On 2011-10-22 18:01, MikeS wrote:
>> I think we're all agreed that the SFD1001 uses the same format as the 
>> 8x50,
>> namely DD, GCR, 100TPI, 500KB/side, and is essentially 1/2 of an 8250.
>>
>
> Agree
>
>> But the question is what did the CBM-900 use, and I would think it much
>> more
>> likely that its 1.2MB UNIX disks would be industry-compatible HD disks
>> instead of somehow squeezing an extra .2MB out of a DD disk that would 
>> not
>> be compatible with anything at all.
>>
>> So I doubt that it was actually compatible with the SFD1001, but I'm just
>> guessing. In any case, if no one comes up with a definitive answer, I'd
>> suggest to the OP that he try using an HD drive and diskette and see
>> whether
>> it works.
>>
>
> Given the fact that I've already tried dumping the disks with an 80 track 
> drive (HD) - I'm leaning more to my own conclusion which is:
>
> I need to get hold of a 100 TPI floppy drive and try that with my 
> kryoflux.
>
> Thanks for your input - I'll keep the list updates on my progress.
>
> Since sources document that aprox 500 CBM-900 prototype units were made 
> I'd have expected that this list was the (only) right place to hear about 
> owners of CBM-900 systems - but it is never too late for any of them to 
> speak up :-)
>
> Thx
>
> /Uffe
>
>
>> ----- Original Message ----- From: "Greg King" <greg.king4@verizon.net>
>> To: <cbm-hackers@musoftware.de>
>> Sent: Saturday, October 22, 2011 5:02 AM
>> Subject: Re: CBM-900 floppy disk format/encoding
>>
>>
>>> From: "William Levak"; on Sat., October 22, 2011; at 01:11 AM -0400
>>>>
>>>
>>>> On Fri, 21 Oct 2011, Ed Johnson wrote:
>>>>
>>>> > I have a SFD 1001 and it used DS/DD diskettes, NOT HD (High Density)
>>>> > diskettes.
>>>>
>>>> The drive mechanism on the SFD 1001 is a Quad Density drive,
>>>> compatible with DD, but not HD.
>>>
>>> "Quad" was a marketting gimmick. It wasn't related to single- and
>>> double-density. It meant that the track density, not the bit density,
>>> was "doubled".
>>>
>>> The 4040 format is 48 Tracks Per Inch, while the 8050 format is 100 TPI.
>>>
>
>
>
>
>
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