On Thu, 14 Sep 2017, Warner Losh wrote:
On Thu, Sep 14, 2017 at 4:05 PM, Fred Cisin <ci...@xenosoft.com> wrote:
On the IBM PC/AT (5170) with 1.2M, admittedly the only one that is easily
readily available, there is trivial software tweaking required to
format/write "720K"/"quad" density, instead of "high" density: 300 bps with
single speed (360RPM) drive; 300 RPM/low density for dual speed drive.
No. But I don't know what you mean with software tewaking.
You need hardware tweaks as well to make the drives compatible. Otherwise
the recording strength is too high.
No. Guess why there's the /HD input on the 5ΒΌ" drive...
The problem is people try to write RX-50 media with the HD drives. The
difference in recording strength causes many of the retention issues. It
works better when you write with the IBM drive with HD media. This may
also be drive specific, as the different drive makers have had different
levels of competence with the old standards...
No. The floppy controller switches the recording density (and thus the
write current) with the /HD line on pin 2 of the 34 pin Shugart bus.
Christian
