Re: Trackstar can use IBM 360K floppy drives to R/W Apple disks?

[david@uow.edu.au (David Wilson)]

"Redskull" <redskulldc@yahoo.com.au> writes:
>By default, 1.2Mb 5.25 floppy drives run at a different RPM, and a different
>bit-transfer rate than 360k 5.25 drives.

I forgot about that.

All 1.2MB drives run at 360rpm (just like 8" floppy drives) in HD mode
with a data rate of 500kbps. This is why they have a lower storage than
a HD 3.5" diskette - same data rate + faster spin = fewer sectors per track
(15 instead of 18).

Some also run at 360rpm in DD mode (giving a faster than normal data rate
of 300kbps).

Others run at the standard 300rpm (250kbps).

>1.2Mb drives can also operate as 720k mode. In this mode they are using
>the same rotational speed and transfer rate as 360k floppies.
>Most 1.2Mb drives can be permanently jumpered for 80Tk DD operation.

Yes, my NEC 5.25 1.2MB drives have those jumper settings.

>The problem then becomes the width of the read/write element in the head of
>the drive,
>and the track density of the drive which is up to 96TPI (tracks per inch)
>instead
>of the 48TPI of the 360k models.

>Rule: Don't write to a Apple floppy with a 1.2Mb drive if you ever plan to
>use it
>in a standard Disk][ drive afterwards.

This was the rule back in the PC/AT days as well - you can read 360KB disks
in a 1.2MB drive but don't use it for writing.
--
David Wilson  School of IT & CS, Uni of Wollongong, Australia