On Fri, Sep 15, 2017 at 1:47 AM, Christian Corti via cctalk < [email protected]> wrote:
> On Thu, 14 Sep 2017, Warner Losh wrote: > >> On Thu, Sep 14, 2017 at 4:05 PM, Fred Cisin <[email protected]> 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 5ΕΊ" drive... The problem is that while that basically works with older drives, it doesn't work with newer drives. There were several discussions in the Rainbow community back in the day about how this drive or that drive didn't write compatible enough RX-50s. > > 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. > It's supposed to be. It isn't always. As someone who helped others with this problem, I know that doesn't always work. I lost my email from this time in a disk crash years ago, or I'd name the brands / versions that were problematic. Warner
