M8207 anyone?

From: ajp166 <ajp166_at_bellatlantic.net>
Date: Wed Aug 9 20:34:40 2000

>Allison's right, an M8027, LPV11 (Q-bus version of the LP11). I'm not
>interested in driving a printer with it, I want to talk to a Zip Drive.
As
>long as I can create a "Centronics" compatible interface (even with all
8
>data bits being output only) I have a chance of getting it to talk to
the
>zip drive. That would give me 100 MB of removable storage, on a PDP-11
that
>would be like heaven.
>
>--Chuck


Read up on parallel ports for PC first, the M8027 WILL NOT be sufficient.
Most
parallel ports ahve enough bidirectional lines and the 8bit data is
bidirectional
(only the old XT ports aren't).

Look into a m7941 (DRV11) parallel line unit sa that give you lots of
bits for
parallel IO. Another would be the M7950 DRV-11B general purpose DMA
interface (also a parallel IO). The latest one was the DRV-11J (M8049)
and that has enough lines to interface anything (32 in and 32 out).

The later boards could possibly even be enough to fake the IDE interface
directly. Even an old clunky 120mb WD2120 would seem large! Seriously
someone has done a Qbus IDE interface adn it's fairly trivial task.
Considering that CDroms, IDE ZIPs, Superdisks and even big hard
drives all can be found real cheap this has appeal. What makes it
mildly hard to do is PDP-11 (Q, U or any) All do a read before write
and IDE control registers don't like that. So you have to do like the DL
cards were the TX and RX registers are different addresses.

I might add that IDE is much faster than ZIP drives, I have a Parallel
port IDE disk and a Syquest 270 and both scream compared to
ZIP.

Allison
Received on Wed Aug 09 2000 - 20:34:40 BST