Thanks.
Sorry about that.
I was, indeed, thinking of floppy drives (RX50), which could have their
own pin 32 and drive select incompatabilities
On Sun, 17 Jan 2021, Paul Koning via cctalk wrote:
2. RD50s are odd; they use pin 32, which is normally drive select 4, as an output to
indicate "I am an RD50". The software looks for that signal. So to emulate an
RD50, install the jumper for drive select 4 (alongside the one for drive select 1) on P7.
On Jan 17, 2021, at 2:12 PM, Fred Cisin via cctalk <[email protected]>
wrote:
Unimportant NIT:
On most drives, pin 32 is side select.
On TRS80 [Model 1], which had single sided drives, pin 32 was the fourth drive
select. (10, 12, 14, 32) The cable connectors had missing pins for three of
those four, and the drive was jumpered to respond to all four. Using four
drives AND adding double sided support required some modifications.
But, on most machines after that, pin 32 is SIDE SELECT. It is used to access
side B of the drive.
On Sun, 17 Jan 2021, Paul Koning wrote:
You seem to be talking about floppy drives. The MFM emulator deals with hard
drives, and the RD50 I mentioned is a hard drive (sold by DEC, 5 MB, the
original hard drive for the PDP-11 base Professional series).
paul
