Installing an operating system on the 11/83 - update.

[Chuck Guzis]

On 2/22/22 16:12, js--- via cctalk wrote:

> As Chuck noted, I'd think you'd want to use 360K media -- not DSHD
> diskettes... and ensure that the 1.2MB drive is slowing down to 300RPM
> with a data rate of 250KHZ.
> 
> These features will depend on the 1.2MB drive you have, as well as your
> FDC and imaging software.

Use low-density media--the high-density stuff really requires higher
write currents (media is formulated for higher magnetic coercivity) to
work to spec.

Any PC that supports 1.2M 5.25" high-density media has a controller that
can vary the clock rate between 250, 300 and 500 Kbit/sec.  Clearly, if
you're using a garden-variety "1.2M" drive, you'd want to use the 300K
data rate, as those drives *generally* spin the disk at 360 RPM. (sort
of a mountain-Mohammed issue.   If you can't slow down the spindle
speed, boost the data rate).

There are several PC (MS-DOS) utilities that can handle this.  You
pretty much need the ones that do low-level controller access, as most
PC software assumes that low-density disks will double-step to get the
standard 48 tpi track spacing).

If you're bamboozled by any of this, drop me a line and I'll shoot you a
simple MSDOS utility that will write RX-50 disk formats on a standard PC.

--Chuck