[TUHS] PDP 11/23 running UNIX version 6 at VCF Midwest!

[Dave Plonka]

Hi Paul

We talked about this a bit more in the comments on the video, with
Gavin doing some experiment afterwards.

While at the show, one experiment we did was to redirection the
bas(1)ic program's output to a file and what we found was that (a)
characters would still sometimes be lost (which is how we determined
it's not due to a serial communications, directly and (b) the dropped
characters would coalesce together into a small run.

Gavin's speculation at the time was that the floppy driver
interfered/interrupted the bas' output somehow, since we noticed there
was also disk activity coinciding roughly in time with a bout of
dropped characters.

What is unusual about Gavin's machine (at the time of this video) is
that everything was on floppies - including root, tmp, etc. because he
did not have a functioning fixed disk yet. It may be a configuration
that was rarely used, e.g., scratch space for bas on floppy. (We found
bas seems to read the source code from the file system even at
runtime.)

Any insights welcome - esp. if you can put them in the comments there.

Peace,
Dave

On Sun, Dec 19, 2021 at 11:25 AM Paul Ruizendaal <pnr at planet.nl> wrote:
>
> While doing some end of year retrocomputing revisiting, I thought some
> of you might enjoy this - there is hope for the next generation(s)! ;)
> https://www.youtube.com/watch?v=_Zyng5Ob-e8
>
>
>
> Thanks for that video link!
>
> I noticed the bit at the end about V6 and  the occasional dropped character and that this was not a serial line issue. I have the same issue in my V6 port to the TI-990 and always assumed that it was a bug I introduced myself when hacking the tty driver.
>
> Does anyone remember, was this a real life bug back in 6th edition back in the 1970’s? Maybe only showing at higher baud rates?
>
> Paul
>


-- 

dave at plonka.us  http://www.cs.wisc.edu/~plonka/