DYSEAC

DYSEAC was the second Standards Electronic Automatic Computer. (See SEAC.)

DYSEAC

DYSEAC van No. 1
Manufacturer	National Bureau of Standards for the U.S. Army Signal Corps
Generation	1
Release date	April 1954; 71 years ago (1954-04)
CPU	900 vacuum tubes and 24,500 crystal diodes
Memory	512 words of 45 bits each (plus 1 parity bit) (mercury delay-line memory)
Weight	20 short tons (18 t)
Predecessor	SEAC

Cross-sectional diagram of a DYSEAC van

DYSEAC was a first-generation computer built by the National Bureau of Standards for the U.S. Army Signal Corps. It was housed in a truck, making it one of the first movable computers (perhaps the first). It went into operation in April 1954.^[1]

DYSEAC used 900 vacuum tubes and 24,500 crystal diodes. It had a memory of 512 words of 45 bits each (plus one parity bit), using mercury delay-line memory. Memory access time was 48–384 microseconds. The addition time was 48 microseconds, and the multiplication/division time was 2112 microseconds. These times are excluding the memory-access time, which added up to approximately 1500 microseconds to those times.

DYSEAC may have been the first computer to implement interrupts for I/O.^[1]

DYSEAC weighed about 20 short tons (18 t).^[2]

See also

• SEAC
• List of vacuum-tube computers