[comp.sys.m6809] Hi-density 177x?

rh2y+@andrew.cmu.edu (Russell E. Hoffman, II) (01/27/91)

Roger Ivie writes:

[stuff deleted]
> so the 1.2 MB drives behave just like an 8-inch drive.

Well, that being the case, I believe there is a hardware hack begging to be
done. Since the 179x and 177x controller can handle 8-inch drives (I know
this 'cuz i designed a 1793-based disk controller for my tenth-grade
science project in high school) by simply inputting a 2 MHz clock instead
of a 1 MHz clock, i beleive a software controlled clock switch would be
about all you'd need to have a 177x / 179x series controller handle the
new types of drives. Of course, you'd need a new device driver for such,
and you'd need to change the definition of the density field in the
descriptor, but I believe this could be a viable simple upgrade
for many OS9/OSk boxes, as most of them tend to use the 179x/177x
Western Digital controllers. The only thing standing in the way (possibly)
is that I don't remember just off the top of my head wheter or not register
reads/writes to the 1793 are synced to the input clock or not. If not,
there should be very little trouble doing this hack. Anybody else out
there who is in the know have any further suggestions?