Re: Disk II Half - Quarter Tracks

["David Wilson" <mcs6502@gmail.com>]

On Feb 10, 4:22 pm, "Alex Freed" <a...@mirrow.com> wrote:
> I don't think that's an issue at all. Consider the standard PC/AT type 1.2
> MB
> 5.25" drive. It can handle "high density" 80 track 1.4 MB disks or "double
> density"
> 40 track 360K disks. Or anything else as long as it is MFM encoding.
>
> It doesn't have to slow down - just data density is lower.
> So the ABILITY to record high density data doesn't mean it can't handle
> slower data.

True. Some 1.2MB drives do not spin at 300rpm even when reading DD
diskettes (which explains why the FD controller needs 3 data rates -
250kb/s, 300kb/s & 500kb/s).

The standard 360/720/1440 (5.25" & 3.5") floppy runs at 300rpm and
250/250/500kb/s. The 8" and 5.25" 1.2MB drives run at 360rpm. When
reading a DD floppy the HD drive may run at 360rpm (300kb/s) or 300rpm
(250kb/s).