ABC

in full American Broadcasting Co.

Major U.S. television network. It began when the expanding national radio network NBC split into the separate Red and Blue networks in 1928. To avoid a communications monopoly, NBC was forced to sell the Blue network in 1941. Its buyer, Edward J. Noble, maker of Life-Savers candies, gave the company its present name. After merging with United Paramount Theaters in 1953, ABC expanded into the emerging television industry and soon became one of the three top networks. It specialized in sports broadcasting and developed the instant replay in 1961. It was bought by Capital Cities Communications in 1985 and by the Walt Disney Co. in 1995.

(Atanasoff-Berry Computer) The first electronic digital computer. Completed in 1942 by Iowa State Professor John Atanasoff and graduate student Clifford Berry, it employed many of the principles of all future computers. For example, although physically in the form of rotating drums, its memory used capacitors that were constantly being recharged like today's dynamic RAM.

It used a standard IBM card reader for input and an odometer-like device for output. For interim storage, Atanasoff devised a base-2 punch and reader that could very quickly store 1,500 bits on paper sheets by electrostatically burning holes in them. The ABC could solve 29 linear equations with 29 unknowns in one 24-hour day, a marvel for its time.

It Took Years for Recognition
John Mauchly, cobuilder of the ENIAC, began corresponding with Atanasoff in 1940 and visited him in 1941. Although Eckert and Mauchly's machine gained international attention, the ABC was recognized years later. A 1973 court overturned an ENIAC patent, stating that the basic ideas of the modern computer came from Atanasoff. In 1990, 87-year-old Atanasoff was awarded the National Medal of Technology. Four years later, an Iowa State University team started to build a replica of the ABC. It took three years to complete, but worked exactly as it was supposed to.

Old and New
At the top, Clifford Berry stands at the real ABC, circa 1942. Below, John Erickson, one of the reconstruction team members, puts a card into the working replica completed in 1997, more than a half century later. (Images courtesy of Iowa State University.)

ABC Components
This shows all the components of the ABC machine. (Image courtesy of Iowa State University.)

1.	(computer)	ABC - Atanasoff-Berry Computer.
2.	(language)	ABC - An imperative language and programming environment from CWI, Netherlands. It is interactive, structured, high-level, and easy to learn and use. It is a general-purpose language which you might use instead of BASIC, Pascal or AWK. It is not a systems-programming language but is good for teaching or prototyping. ABC has only five data types that can easily be combined; strong typing, yet without declarations; data limited only by memory; refinements to support top-down programming; nesting by indentation. Programs are typically around a quarter the size of the equivalent Pascal or C program, and more readable. ABC includes a programming environment with syntax-directed editing, suggestions, persistent variables and multiple workspaces and infinite precision arithmetic. An example function words to collect the set of all words in a document: HOW TO RETURN words document: PUT IN collection FOR line in document: FOR word IN split line: IF word not.in collection: INSERT word IN collection RETURN collection Interpreter/compiler, version 1.04.01, by Leo Geurts, Lambert Meertens, Steven Pemberton <Steven.Pemberton@cwi.nl>. ABC has been ported to Unix, MS-DOS, Atari, Macintosh. http://cwi.nl/cwi/projects/abc.html. FTP eu.net, FTP nluug.nl, FTP uunet. Mailing list: <abc-list-request@cwi.nl>. E-mail: <abc@cwi.nl>. ["The ABC Programmer's Handbook" by Leo Geurts, Lambert Meertens and Steven Pemberton, published by Prentice-Hall (ISBN 0-13-000027-2)]. ["An Alternative Simple Language and Environment for PCs" by Steven Pemberton, IEEE Software, Vol. 4, No. 1, January 1987, pp. 56-64.]