Duty officer signup sheet for the U.S. Navy Bureau of Ships Computation Project at Harvard University, which built and operated the w:Harvard Mark I, one of the earliest digital computers. The Mark I was in operation from 1944 to 1959. During that period, the days of the week and dates on the form, e.g. Monday, 23 April, match up for the following years: 1945, 1951 and 1957. Grace Hopper, noted computer pioneer, worked on the project from 1944 to 1949.