Subject: Re: Further confusion
To: Russ Zaccari <>
From: Dave McGuire <>
List: port-vax
Date: 03/14/1996 16:10:19
On March 14, you wrote:
> 1)  the internal hard drive dub0 and tape drive mua0  are no longer operations.

  This may be a backplane/card ordering problem.

> 2)  the controller for the internal RD54 is set for dub and I'd like to change it to
> 	dua.  From looking at the card the only identification I can find is
> 	SCD-RQD11/EC.  There are three switch banks SW1 (1-4:  1+4 on),
> 	SW2 (1-10: 3+9 on) and SW3 (1-4:  1+2+3+4 on).

  This sounds like a 3rd party controller, not a DEC board...Can you
identify a manufacturer on there anywhere?

> My questions are:
> 1)  can I connect the RD53 to the RQD11?  there are what appears to be 4
> 	data connectors on this board.

  Almost definitely yes...Now it's almost definitely a 3rd party
controller.  Are your two drives "real" rd53/rd54, i.e. is the rd53 a
Micropolis 1325 and is the rd54 a Maxtor XT-2190?  If so, they're both
MFM drives, and if at least one of them was connected to your RQD11
controller, then your controller is MFM.  ESDI uses the same
connectors, and ESDI controllers are common in the 3rd-party DEC QBUS
market, that's what I was concerned about. 

  If they're both MFM, and your RQD11 controller is MFM and has extra
data connectors, then it's just a matter of daisy-chaining the control
cable and plugging in the data cable.

  I was gonna draw an ascii-art layout of the backplane...but I think
someone did that recently...Let me know if you can't find it..