PDP 11/15

[Randy Dawson]

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.


________________________________
From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Paul Anderson via cctalk <cctalk at classiccmp.org>
Sent: Tuesday, June 18, 2019 7:16 PM
To: General Discussion: On-Topic and Off-Topic Posts; cctech at vax-11.org
Subject: PDP 11/15

I bought a large package of DEC gear last year and it came with a PDP
11/15. I have no need for this classic, and put it on the list. A few
people responded, but because of my problems, I never followed up with
them.

For those who responded, I apologize for dropping the ball. If anyone is
interested in it, please contact me off list.

BTW, I have started on pulling a few things out of the warehouse.

Thanks, Paul