Help! need 400k/800k Mac os 6 or 7 diskettes!

From: Eric Smith <eric_at_brouhaha.com>
Date: Tue Oct 7 06:28:41 2003

>>Apple stopped having the drives read and write 400 and 800 k disks a
>>while ago.
>
> Actually the System does that... I don't remember when though. I
> think it might have been System 8 that stopped reading 400k,

The software support went away, but also they stopped making drives
(and controller chips) that can handle the 400K and 800K formats.
Since they used variable motor speed on the 400K, 800K, and Superdrive
(FDHD), they could keep a roughly constant flux density on the track.
But when you try to read or write that on a fixed-speed drive, such
as a 1440K drive in a PC, or any recent Mac floppy drive, the frequency
required to match the flux density of 400K/800K disk format is outside
the range that the drive electronics can reliably handle. Reading can
sometimes be done, but writing is very problematic.
Received on Tue Oct 07 2003 - 06:28:41 BST