On Thu, 15 Mar 2001, Elmet Orasson wrote:

> On Thu, 15 Mar 2001, Johnny Billquist wrote:
> 
> > On Thu, 15 Mar 2001, Elmet Orasson wrote:
> > 
> > > 	This beast normally uses Massbus. Has DEC or some other
> > > manufacturer ever created a SCSI card for it? If there is such a card
> > > out there then I'm very interested of getting hold of one :-)
> > 
> > The 11/750 isn't a MASSBUS computer as such. The "general" bus of the
> > 11/750 is the Unibus.
> > And yes, there exist several SCSI controllers for the Unibus.
> 
> 	I have to admit - I know quite little about 11/750 hardware
> and how it operates, but this will probably change :-) At this time
> there are 2 RP07-s and one CPU cabinet that work and 1 CPU and drive
> for spares.

You'll have a fun ride! :-)

Anyhow, expect performance to be slightly worse with the SCSI
controllers. RP07 is a pretty fast drive. I'm not sure if the 11/750 can
swallow data at 2.4MB/s, otherwise it's just 1.2MB/s, but the massbus is
hooked to the CPU and memory without going through the Unibus. The Unibus
is rather slow, which don't make for optimal performance. :-)

> 	And yes, Massbus is used for attaching the drives. But those
> drives (in my case RP07-s) are also huge, power hungry and
> considerably old. So i'm looking for SCSI card in hope to use some
> older SCSI drives as a replacement.

I'm a bit impressed that you have two RP07s on the machine. They were also
rather expensive at the time, and just about top of the line high-tech
wise. They are very impressive drives. I know some sites who considered
RP07s to also be suceptible to break down when they got old, though I
don't have that impression myself about them.

	Johnny

Johnny Billquist                  || "I'm on a bus
                                  ||  on a psychedelic trip
email: bqt@update.uu.se           ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol