Re: C900 floppy format.

From: Francesco Messineo <francesco.messineo_at_gmail.com>
Date: Wed, 21 Oct 2020 09:06:37 +0200
Message-ID: <CAESs-_zT-t38zNPx34YUOwJy_BOhbVChTaS9i5Up4WOVaa3nAw_at_mail.gmail.com>
On Wed, Oct 21, 2020 at 8:11 AM André Fachat <afachat_at_gmx.de> wrote:
>
>
>
> Am 20. Oktober 2020 14:38:35 schrieb Gerrit Heitsch <gerrit_at_laosinh.s.bawue.de>:
>
>> On 10/20/20 2:23 PM, Michał Pleban wrote:
>>>
>>> tokafondo wrote:
>>>
>>>> Does anyone has been able to transfer Commodore C900 disks to a 5.25" double
>>>> density, double track disk?
>>>
>>>
>>> What do you mean by "transfer the disks"? Do you mean using DSDD disks
>>> instead if DSQD in the C900 floppy drive? it is possible just like with
>>> the 8250, most DSDD disks can be formatted but they won't be very reliable.
>>
>>
>> Never had a problem with using DSDD in a 8050 drive which is a 8250 with
>> only a single head.


there's no "QD" magnetic media, SD/DD/QD magnetic media was always the
same (300 oersted).
Probably the diskettes sold as QD/96 tpi were just higher quality.
See here for all you ever wanted to know about floppy disks:
https://www.retrotechnology.com/herbs_stuff/drive.html

When I was at the university, we had  a couple of Olivetti LSX 3xxx
Unix servers, the consoles had 96tpi 5.25" disk drives (not the HD
ones),
I've seen only once a box of floppies certified for 96tpi, all the
other media was regular DSDD 48tpi and most of those disks are still
readable today (I've collected them
when the machines were put out of service). I've had more failures on
the 96tpi disks, interestingly enough.

Frank
Received on 2020-10-21 10:00:03

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