The PDP-1, installed in 1961, was the first effective mini-computer at Lawrence Livermore National Laboratory. It was originally intended to support the input/output functions: card-to-tape, tape-to-printer, and tape-to-film. The PDP-1's ability to handle I/O freed up the large systems to run major codes.
A more important purpose of the PDP-1 was as a test machine; code could be tried there before it was transferred to the large machines. Computation staff called the PDP-1 their "Romper Room" because "all of us were very much learners and idea try-outers. Here, we could play around with all sorts of things that might be useful on the larger 'Physics Computers,' and not be badgered by others needing to use the computer." Feedback on the PDP-1 was immediate since the programmer could sit at the console to write and correct programs.
Cecilia Larsen is in the center; Bob Kuhn at the right. The man on the left is unidentified.