File:SEACComputer 015.jpg

English: The Air Force at first supported the development of the UNIVAC for use in speeding up their planning and deployment (Project SCOOP), but when in 1948 it became apparent that the machine would not be finished in time, Air Force officials asked NBS to undertake a crash program to build a computer. It became SEAC, which became operational in April 1950.

Shortly after SEAC began operation, magnetic wire was installed to replace punched tape as input. This increased the reading time from 30 to 10,000 words per minute. The SEAC’s operators attached one of the machine’s registers to an amplifier and speaker so that the malfunctions in the computer’s routines could be identified by unfamiliar sound patterns. At the end of this particular program cartridge [pictured] there are programs that play ‘Camptown Races,’ ‘Dixie,’ and ‘America’- a diversion demonstrating the programmers’ skills.

The memory in SEAC consisted of sixty-four mercury-filled glass tubes with one quartz crustal at each end (one as a transmitter and one as a receiver). Each acoustic delay line [pictured right] had a capacity of eight words- one word being a sequence of information bits in the form of sound waves traveling through mercury.