PDP-11: Disk over Serial proposal

Pete Turnbull <pnt103@cs.york.ac.uk> pete at indy.dunnington.york.ac.uk
Mon Dec 8 07:10:43 AEST 1997

On Dec 7, 10:05, Tim Shoppa wrote:
> > > Many (most) Q-bus processors have TU58 bootstraps in firmware.
> > > Certainly all 11/73B, 11/83, 11/93, 11/84, and 11/94 have the
> > > bootstraps.
> >
> > Are you sure, Tim?  My 11/73 doesn't

> Is this a KDJ11A (dual-height, no boot ROMs on the CPU board) or

Well, my KDJ11 systems are somewhat non-standard, so it's possibly not
relevant. I can't easily check ATM, as they're running live Unix systems :-)
 My point
was that I didn't think the TU58 was in all revisions of the bootstrap ROMs.

I know how to get the information (from a variety of revisions and CPUs)
because I not only have the documentation, I used to be employed as a
maintenance 'engineer' on QBus systems.

> Part of the confusion may lie in the fact that TU58's appear to the system
> to be disk (block-addressable) instead of tape devices :-).

Indeed, but we both know that DD means tape :-)

> The downside,
> of course, is that it's a disk with a 30-second seek time!

But still better than some systems.  (Fond memories of TU56's on a PDP8, and
not-so-fond memories of friends' Commodore disks, which seemed slower even
than that).

And as Tim points out, RSP is well-defined, tried, and tested.


Pete						Peter Turnbull
						Dept. of Computer Science
						University of York

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