CALDIC (the California Digital Computer) was an electronic

digital computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These progra ...

built with the assistance of the

Office of Naval Research The Office of Naval Research (ONR) is an organization within the United States Department of the Navy responsible for the science and technology programs of the U.S. Navy and Marine Corps. Established by Congress in 1946, its mission is to pla ...

at the

University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant u ...

between 1951 and 1955 to assist and enhance research being conducted at the university with a platform for high-speed computing. CALDIC was designed to be constructed at a low cost and simple to operate. It was a

serial decimal In computers, a serial decimal numeric representation is one in which ten bits are reserved for each digit, with a different bit turned on depending on which of the ten possible digits is intended. ENIAC and CALDIC used this representation. See al ...

machine with an , 10,000-word magnetic drum memory. (As CALDIC's decimal words were 10 digits each, the magnetic memory could store about 400,000 bits.) It contained 1,300

vacuum tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. The type kn ...

s, 1,000 crystal diodes, 100 magnetic elements (for the recording heads), and 12

relay A relay Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts An automotive-style miniature relay with the dust cover taken off A relay is an electrically operated swit ...

s (in the power supply). It weighed about . It was capable of speeds of 50 iterations per second. CALDIC was a

stored program A stored-program computer is a computer that stores program instructions in electronically or optically accessible memory. This contrasts with systems that stored the program instructions with plugboards or similar mechanisms. The definition ...

computer with a six-digit instruction format (two digits for the

opcode In computing, an opcode (abbreviated from operation code, also known as instruction machine code, instruction code, instruction syllable, instruction parcel or opstring) is the portion of a machine language instruction that specifies the opera ...

and four digits for the memory address). The computer was initially planned by

Paul Morton Paul Morton (May 22, 1857 – January 19, 1911) was a U.S. businessman, and served as the 36th Secretary of the Navy under Theodore Roosevelt. Biography He served as the U.S. Secretary of the Navy between 1904 and 1905. Previous to thi ...

, Leland Cunningham, and Dick Lehmer; the latter two had been involved with the

ENIAC ENIAC (; Electronic Numerical Integrator and Computer) was the first programmable, electronic, general-purpose digital computer, completed in 1945. There were other computers that had these features, but the ENIAC had all of them in one pac ...

at the

University of Pennsylvania The University of Pennsylvania (also known as Penn or UPenn) is a private research university in Philadelphia. It is the fourth-oldest institution of higher education in the United States and is ranked among the highest-regarded universit ...

, and Lehmer had given one of the

Moore School Lectures ''Theory and Techniques for Design of Electronic Digital Computers'' (popularly called the "Moore School Lectures") was a course in the construction of electronic digital computers held at the University of Pennsylvania's Moore School of Electrical ...

. Morton oversaw the design and construction with a team comprising electrical engineering graduate and undergraduate students at the university, more than 35 in total, including

Doug Engelbart Douglas Carl Engelbart (January 30, 1925 – July 2, 2013) was an American engineer and inventor, and an early computer and Internet pioneer. He is best known for his work on founding the field of human–computer interaction, particularl ...

(who later invented the

computer mouse A computer mouse (plural mice, sometimes mouses) is a hand-held pointing device that detects two-dimensional motion relative to a surface. This motion is typically translated into the motion of a pointer on a display, which allows a smooth ...

) and

Al Hoagland Albert Smiley Hoagland ('Al Hoagland') (September 13, 1926 – October 1, 2022) had a long career on the development of hard disk drives (HDD) starting with the IBM RAMAC. From 1956 to 1984, he was with IBM in San Jose, California and then fro ...

(a pioneer of the computer disk industry). The machine was first ready for use in the summer of 1953 and mostly operational in 1954. Development cost through July 1955 was approximately $150,000.

References

External links

Berkeley Hardware Prototypes

* ttp://www.cs.berkeley.edu/~pattrsn/Arch/CALDIC/index.html CALDIC photos and diagrams One-of-a-kind computers Vacuum tube computers {{Compu-hardware-stub

See also

References

External links