FDDI, was: Re: [rescue] u2 drive trays

Dave McGuire mcguire at neurotica.com
Wed Aug 20 10:40:59 CDT 2003

On Wednesday, August 20, 2003, at 05:24 AM, Jochen Kunz wrote:
>>    DEC's PDQ-based FDDI controllers are:
> [...]
>>    DEFQA (Qbus...which is slower than FDDI!)
> BTW: I have a DEFQA in my VAX 4000-400. If I can get docs about this
> DEFQA beast I may write the QBus attachment for NetBSD. Wouldn't it be
> nice to have NetBSD VAX on the FDDI ring? :-)

   Yeah that'd be neat...I just wish Qbus weren't so blasted SLOW.

   Qbus was a introduced as a smaller, lower-cost alternative to Unibus, 
which runs at TWICE the speed of Qbus.  (Qbus multiplexes the address 
and data lines on the same backplane wires) If they really had to 
discontinue one and keep the other, they should have kept Unibus!

   So much for "newer" automatically being "better".


Dave McGuire                 "You don't have Vaseline in Canada?"
St. Petersburg, FL                     -Bill Bradford

More information about the rescue mailing list