>> Q-bus or Unibus controller. (On some Rainbows, it is possible to low-level
>> format RX50 media directly.)
>You say 'some Rainbows'. I thought this was just a software
>consideration, and that the hardware of all 'bows was capable of
>formatting blank disks. Since the 'bow disk controller is just a WD179x
>chip (IIRC) on one of the micro's buses, it seems hard to figure out a
>way to stop it from formatting, although anything is possible.
On a Rainbow, a dedicated Z80 does the floppy I/O; the formatting
code has to be in the Z80's firmware (which, indeed, is a "software
consideration".). In some revisions of the Z80's firmware,
the format option for RX50's isn't present (it returns an error).
I'm currently looking for the "RX50 FAQ", put together by Charles
Lasner most of a decade ago, in hope that it discusses which firmware
revisions are/aren't capable of formatting. So far I've turned up
about 30 pages of Charles's notes on RX50 interleave issues, but
nothing about the Rainbow firmware!
--
Tim Shoppa Email: shoppa_at_trailing-edge.com
Trailing Edge Technology WWW: http://www.trailing-edge.com/
7328 Bradley Blvd Voice: 301-767-5917
Bethesda, MD, USA 20817 Fax: 301-767-5927
Received on Tue May 25 1999 - 16:56:59 BST