MFM or ESDI QBUS controller for one PDP-11/23 PLUS

Sergio Pedraja spedraja at
Tue Oct 9 08:37:02 CDT 2007

Hi, Jerome:

Then perhaps you can describe your other hardware - backplane
> with power supply.  Do you have a BA23 or a BA11 box?  Or
> something else?  What about the serial ports, etc.?

The PDP-11/23-PLUS comes in one BA11. I have another BA11 plus the boards to
connect both, but this is not important for this matter, I think.

I have too one PDP-11/53 ( not sure at all) who uses one BA23. It's state is
not good in excess, but I don't want to dismantle it... by now.

I agree that the RQDX1, RQDX2 and RQDX3 require a distribution
> panel of some sort to change from the 50 pin cable to the
> 34 pin / 20 pin cable required by MFM hard drives and floppy
> drives.  That panel is usually part of a BA23 box.  A BA123 box
> uses a distribution board which can handle 4 drives, but the
> hard drives also require an additional READY / WRITE PROTECT
> (very small) panel.
> Probably a 3rd party controller like the Dilog DM01 is what
> you are looking for.  But I suspect that these days, an RQDX3
> is probably more easily found - except for that internal
> distribution panel which is also required if you are using
> a BA11 box.

Well, this is something :-) I didn't hear about the DM01 previously. This is
helpful, but I accept pleasantly other suggestions and, of course, any offer
about items like this one (for example). Don't forget the ESDI option that
I've mentioned previously.

And, of course, we ever have the option of one SCSI board, but I am not sure
about what was the better option for one QBUS PDP. QMD Perhaps ? I have too
one SCSI Hard Disk but not sure even if it works :-)

Thanks and Greetings

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