Legends of Technology - Aiken, Howard | HackTHatCORE

Image Source: Computer History Museum

Aiken, Howard

(1900 - 1973)

American, Electrical Engineer

Howard Hathaway Aiken was a pioneer in the development of automatic calculating machines. Born on March 8, 1900, in Hoboken, New Jersey, he grew up in Indianapolis, Indiana, where he pursued his interest in electrical engineering by working at a utility company while in high school. He earned a B.A. in electrical engineering in 1923 at the University of Wisconsin. By 1935, Aiken was involved in theoretical work on electrical conduction that required laborious calculation. Inspired by work a hundred years earlier, Aiken began to investigate the possibility of building a large-scale, programmable, automatic computing device. As a doctoral student at Harvard, Aiken aroused interest in his project, particularly from Thomas Watson, Sr., head of International Business Machines (IBM). In 1939, IBM agreed to underwrite the building of Aiken’s first calculator, the Automatic Sequence Controlled Calculator, which became known as the Harvard Mark I.

MARK I and its progeny

Like Babbage, Aiken aimed for a general-purpose programmable machine rather than an assembly of special-purpose arithmetic units. Unlike Babbage, Aiken had access to a variety of tested, reliable components, including card punches, readers, and electric typewriters from IBM and the mechanical electromagnetic relays used for automatic switching in the telephone industry. His machine used decimal numbers (23 digits and a sign) rather than the binary numbers of the majority of later computers. Sixty registers held whatever constant data numbers were needed to solve a particular problem. The operator turned a rotary dial to enter each digit of each number. Variable data and program instructions were entered via punched paper tape. Calculations had to be broken down into specific instructions similar to those in later low-level programming languages such as “store this number in this register” or “add this number to the number in that register”.
The results (usually tables of mathematical function values) could be printed by an electric typewriter or output on punched cards. Huge (about 8 feet [2.4 m] high by 51 feet [15.5 m] long), slow, but reliable, the Mark I worked on a variety of problems during World War II, ranging from equations used in lens design and radar to the designing of the implosive core of an atomic bomb. Aiken completed an improved model, the Mark II, in 1947. The Mark III of 1950 and Mark IV of 1952, however, were electronic rather than electromechanical, replacing relays with vacuum tubes. Compared to later computers such as the ENIAC and UNIVAC, the sequential calculator, as its name suggests, could only perform operations in the order specified. Any looping had to be done by physically creating a repetitive tape of instructions. (After all, the program as a whole was not stored in any sort of memory, and so previous instructions could not be reaccessed.)
Although Aiken’s machines soon slipped out of the mainstream of computer development, they did include the modern feature of parallel processing, because different calculation units could work on different instructions at the same time. Further, Aiken recognized the value of maintaining a library of frequently needed routines that could be reused in new programs -- another fundamental of modern software engineering. Aiken’s work demonstrated the value of large-scale automatic computation and the use of reliable, available technology. Computer pioneers from around the world came to Aiken’s Harvard computation lab to debate many issues that would become staples of the new discipline of computer science. The recipient of many awards including the Edison Medal of the IEEE and the Franklin Institute’s John Price Award, Howard Aiken died on March 14, 1973, in St. Louis, Missouri.

References:

• Cohen, I. B. Howard Aiken: Portrait of a Computer Pioneer. Cam- bridge, Mass.: MIT Press, 1999.
• Cohen, I. B., R. V. D. Campbell, and G. Welch, eds. Makin’ Num- bers: Howard Aiken and the Computer. Cambridge, Mass.: MIT Press, 1999.