PDP-11/45 RSTS/E boot problem

Alan Frisbie frisbie at flying-disk.com
Tue Feb 12 14:51:11 CST 2019

> >     > Likely some disk controllers did NOT SUPPORT crossing 64K boundaries!
> >
> > No; the RK11 spec says "[the two extended memory bits] make up a two-bit
> > counter that increments each time the RKBA overflows".
> >
> > The actual error turns out to be slightly different to my guess; there's
> > a spurious overflow from the low 16-bit register to these bits at 0170000.
> Maybe a problem with E29 or E34 on the M795 module?

I am finding this entire discussion extremely fascinating!
Every day I look forward to reading the latest twists in the
plot.   The ideas, hunches, tests, dead ends, and results are an
excellent example of the debugging process.

I am awaiting the exciting Perry Mason style conclusion, where
the guilty chip stands up and confesses on the stand.  :-)

Alan "Where were you on the night of the crime?" Frisbie

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