PDP 11/15

[Jacob Ritorto]

On Tue, Jun 18, 2019 at 11:15 PM Randy Dawson via cctalk <
cctalk at classiccmp.org> wrote:

> Paul,
> That is so cool!
> How much space would it take?
> That is my first computer (outside of timesharing and Z-80 homebrew).
> My first job was on the PDP-15 to transcribe the APOLLO analog range tapes
> of the lunar experiments, primarily the seismometer moonquake data for the
> University of Texas Geophysics Lab (they designed the seismometers).
>
> The machine was a pretty good wall, 4-5 racks.  On the other side of the
> room were the FM/Direct Bell and Howell analog range tape players and
> demodulators.
> I ran this stuff all night long, hanging tapes, using the scope to adjust
> analog heads for the best signal and transcribe to the digital tape.
> NASA was not interested in this stuff anymore, they were onto Skylab.  The
> ALSEP lunar stations were TEG powered and would go on for decades
> transmitting, probably still are.  All we got was freetime gratis from the
> range stations to point at the moon and hang a tape, the data was always
> bad and a challenge to tweak heads the best we could.
>
> We had a Versatec electrostatic plotter to output the continuous seismic
> record as I was decoding the tapes.
> Anytime there was an 'event' on the plotter, I had Dr. Yosio Nakamura's
> home number to call him in and take a look.
>
> Many nights, we re tweaked heads, to get the last bits of clean
> seismometer data.
>
> Randy
> Trivia: As I hung a tape out of sequence once, Fortran coders fixed that
> next day.  Next time it happened, the TTY chatters, RANDY! DIDN'T YOU
> ALREADY ENTER GMT JULIAN DATE XXX:XXX:XXX
> It was a all night job alone in the computer room, and I am listening  to
> Foghat between tape hangs and alignment.
>
>
>

You know, one of the reasons I'm still on here is for the anecdotes
and this is far and away the coolest anecdote I've read in quite some time!


Thanks for sharing, Randy; more, please!