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The Digital Equipment Corporation PDP-11/50, 1975. The photo is from a DEC manual. Ours looked about the same but there was at least one more cabinet to the left for tape drives, plus an RP04 disk drive. The rectangular black panels on the cabinets pop out for access to the insides. The PDP-11 console pulls out like a drawer. The hardcopy terminal is an LA36 DECwriter.
Columbia's PDP-11/50 was housed in 208 Computer Center 1975-1982 and ran DEC's RSTS/E operating system as a pilot project in open timesharing. 32 terminal cables came in at the back, initially hardwired to public terminals downstairs, later to the PACX terminal switch, and thus accessible from all over campus. The experiment was a success and the PDP-11/50 was retired in 1982 in favor of the larger and more general-purpose DEC-20s.
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The PDP-11 console (ours is shown, photo by Ben Beecher) had switches and lights. The lights show the address and contents (bits) of a selected location. When the CPU had nothing else to do (increasingly uncommon as the system became more popular) it played a "movie" on the light bank. Each operating system (RSTS/E, RT-11, RSX-11, etc) had its own movie -- groups of four lights moving left to right, right to left, or in a circle between the two light banks. The Massachusetts General Hospital Multi-User Multi-Processing Operating System (MUMPS) had the lights throbbing in and out from the center like a bad case of mumps. This was the sort of thing that gave the DEC world an aura of "fun", compared to the "serious" IBM world ("this page intentionally left blank"). Here's another shot illustrating the cheerful color scheme:
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Here are a few more photos taken (by me, circa 1976) in Columbia's PDP-11 room. Click on a photo to enlarge it.
By the way, I had had a job for a while at Mount Sinai Hospital in NYC in the early 1970s, working on PDP-11s with DOS/Batch. Somebody recently (2003) asked what DOS/Batch was like; my recollections from 1972, when I worked at the Mount Sinai Hospital Computer Science Laboratory:
You punched cards, read 'em into the reader, got the results back on the line printer. Those of us who used the machine to develop software or do production runs (e.g. hunting through a tape to compile and correlate data on anal fissures) would take turns. No multiprocessing, each person had the machine all to her/himself, switches, lights, DECtapes, RK05s, and all. There was a Teletype console with a minimalistic "monitor" (shell), where you could activate jobs from the card reader, DECtape, paper tape reader, etc, and use PIP (Peripheral Interchange Program) to manage files (move, rename, delete, copy, etc).Links:Of course, a batch job could run a program that interacted with the teletype or other devices. The one I remember best had to do with cervical cancer. One of the treatments was for the surgeon to manually insert radioactive needles into the tumor. You can imagine, it took time and patience to get the needles in just right, to maximize the dose to the tumor and minimize the dose to healthy tissue. So doctors who performed this procedure a bunch of times began to suffer from the radiation.
Lee Lidofsky, a professor of Nuclear Engineering and Medical Physics at Columbia (whom I had worked for in the late 60s and early 70s and who steered me towards a career in computing) came up with an ingenious solution, one that would not have been possible a few years earlier: let the doctor shove the needles in any old way, as fast as possible, then take a stereo X-ray of the area, dash over to the computer lab, where we would "scan" the X-rays; the software would create a 3D model, display it on a storage tube, and then the doctor interacts with the graphic (using a light pen) to specify the tumor boundaries. Then the software figures out the 3D dose contours (by solving tons of simultaneous equations that would take weeks or months to do by hand), displays the isodoses on the tube, and prints out instructions stating the optimum time at which to remove each needle, thus maximizing the dose to the tumor and minimizing the dose to healthy tissue of both the patient AND the doctor. The doctor runs back to the operating room and follows the instructions.
All this in, what, 32K? And yes, the computer really, really had to be up when the doctor burst in with those X-rays! As far as I know, it always was.
