On Sat, 6 Mar 2004, Bill Pechter wrote:

> > On Fri, 5 Mar 2004, John Hudak wrote:
> >
> > > Ahh yes, RK07 did have hardware support for dual porting...but...I don't
> > > think any of the DEC OSs took advantage of it..That was why I decided to
> > > write one in my spare time to run under RT-11.....waaaaaay long time ago....

> >
> > RSX does. As does VMS. But it only uses it for two controllers on the same
> > machine. Dual-path disks. If you want to access a disk, and the controller
> > is busy, the OS will go to the other controller and try.

>
> RSX does and one of my old customers when I was at DEC used it dual
> ported between machines. I think they used 11M -- but they also
> had IAS...


Ah, yes. Failover... I think it also works fine if you do read-only.

> The dual port diags failed on the
> 11/70s due to timing problems (the diags had timing loops
> that probably never were tested on the 11/70) and failed but the OS
> ran error free. The engineers there were unhappy that the diags failed
> even though the software worked perfectly. Diag engineering
> pretty much didn't care (it was the mid 80's) and the 11/70 and RK07's
> were out of production.


The Unibus on the 11/70 was rumoured to be the slowest Unibus of them all.
I do know that there are limits on peripherials on an 11/70 combined with
an RK611 if you read the documentation. Atleast as officially supported.
You can get away with a lot of things that DEC didn't support...

> d|i|g|i|t|a|l had it THEN. Don't you wish you could still buy it now!
> bpechter@shell.monmouth.com|pechter@ureach.com


Yup. :-)

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
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