Here's a publicity photo from about 1972, showing Ken and Dennis in front of a PDP-11. From the right, the major items of equipment are
• At the far right, on the table, are what someone discerned was a VT01A storage-tube display (based on Tek 611) and a small keyboard for it. Slightly hard to make out.
• A main CPU cabinet, partly behind the table. The processor is a PDP-11/20; it must have been our second one, with the Digital Special Systems KS-11 memory management unit. Our very first just said "PDP11," not "11/20." The arrays of distorted rectangles above it and in other cabinets are the labels on DECtape canisters.
• Another cabinet. Careful examination of the image by Steve Westin detects the top of the bezel of an 11/45 CPU barely peeking above the TTY to the right of the one Ken is typing at. A paper tape reader is above it.
• The third cabinet sports a dual DECtape drive at the top.
• A cabinet with another DECtape drive, probably also containing BA-11 extension boxes within.
• A cabinet with RK03 disk drives. These were made by Diablo (subsumed by Xerox) and OEMed to Digital. Digital later began manufacturing their own version (RK05).
• A cabinet containing RF11/RS11 controller and fixed-head disks. By this time / and swap space lived there, while /usr was on the RK03s.
• On top of the machine are what look like magtapes. A probable TU10 transport is barely visible just below Ken's chin.
In front, we have
• Ken (sitting) and Dennis (standing), both with more luxuriant and darker hair.
• Two Teletype model ASR 33 terminals.
(Photo and description courtesy of Dennis Ritchie.