Adding floppy drives to my PDP-11?

allison allisonportable at
Sat Apr 13 22:24:46 CDT 2019

On 04/13/2019 06:07 PM, Charles via cctalk wrote:
> I have a PDP-11/23+ with two RL02's in a corporate cabinet but no
> floppy drives. Also an RXV21 (M8029) card.
> My PDP-8/A has RX01 drives, and I was hoping just to run the cable
> over to the -11 when I wanted to use floppies on it.
> But after some searching, it appears that the RXV21 will only work
> with an RX02 drive...
> Just wondering what my options are for hooking up any kind of floppy
> drives.
> I could sell the RXV21 and buy/trade for an RXV11 (M7946) instead, to
> use with the RX01 in the other rack.
> Or look for an RX02 that won't break the bank - but that won't fit in
> the corporate cabinet. I do have another cabinet but it's got other
> rack-mount gear in it at the moment.
> What about smaller drives (RX50? RX33?)... can those be interfaced to
> the 11/23+ Qbus?
> Other thoughts?
> thanks
> Charles
RX50, RX33, RX23 aall work with the RQDX2,3 controllers The boards and
cables are fairly easy to find as they were
used in microPDP11 and Qbus Microvax.  Depending on the CPU they will be
bootable (11/23+ I believe works).
IF you lucky and can fine a quantum D540 or St225 you can have a hard
disk as well.  I have 11/23+ and 11/73
configured using that (rqdx2 in one and Rqdx3 in the other) and the
breakout board.

Many people skip over the MSCP controller for MFM hard disks as the hard
drives are scarce, but floppies
a Teac FG55GFR is the hot item as would be a RX50 or 1.44 3.5" floppy or
all three as it can interface not
less than two floppy drives.


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