Unibus disk controller with modern storage

[Pete Lancashire]

To solve the loading problem a division of Tektronix built their own Unibus
repeater.
We not only had a lot of stuff attached to the Unibus but was in multiple
rack instruments.
We also went with round cables the Tektronix made internally. We also made
our own Unibus
cables and added a few LEDs to the paddle boards, power status was one of
them. Can't
remember what the others were far.

A picture of the first generation of the system

http://www.eetimes.com/author.asp?doc_id=1320717&image_number=1

By the time I ended up at Tek the PDP11 had been renamed CP-1160 and came
in custom
colors of light and dark blue.

The Unibus had to make it from the PDP to a couple of the boxes near the
lower left.

On Fri, Oct 21, 2016 at 11:50 AM, Guy Sotomayor Jr <ggs at shiresoft.com>
wrote:

>
> > On Oct 21, 2016, at 11:41 AM, Paul Koning <paulkoning at comcast.net>
> wrote:
> >
> >
> >> On Oct 20, 2016, at 6:05 PM, Noel Chiappa <jnc at mercury.lcs.mit.edu>
> wrote:
> >>
> >>> From: David Bridgham
> >>
> >>> the right threshold voltage to meet the receiver spec
> >>
> >> The UNIBUS spec says the 4 crucial receiver parameters are input
> thresholds
> >> (high and low), and the input currents (high and low); the crucial
> >> transmitter parameters are the output low voltage (at 50 mA sink), and
> >> the output high leakage current.
> >
> > Where did you find those specs?  I see a Unibus Spec on Bitsavers, but
> it doesn't appear to mention the electrical specs.
> >
>
> They exist in various DEC handbooks.  I don’t recall which one had them.
>
> The specs are fairly stringent in order to meet the max unibus bus lengths
> (my 11/40 is close to max).
>
> TTFN - Guy
>
>
>