ABC

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ABC

ABC

1. Abbr. for “aggregate base course.”
2. Abbr. for “Associated Builders and Contractors.”

ABC

(computer)

ABC

(language)
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.]

ABC

(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 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 (see DRAM).

The ABC used a standard IBM card reader for input and an odometer-like device for output. For interim storage, Atanasoff devised a binary 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, Atanasoff was not recognized until years later. A 1973 court overturned an ENIAC patent, stating that the basic ideas of the modern computer came from Atanasoff. Some 17 years later at the age of 87, he was finally honored by receiving the National Medal of Technology.

In 1994, an Iowa State University team started building a replica of the ABC. It took three years to complete, but worked exactly as it was supposed to.


Old and New
Clifford Berry (top) stands at the original ABC, circa 1942, while John Erickson, reconstruciton team member (bottom), puts a card into the replica that he helped build more than a half century later. (Images courtesy of Iowa State University.)


Old and New
Clifford Berry (top) stands at the original ABC, circa 1942, while John Erickson, reconstruciton team member (bottom), puts a card into the replica that he helped build 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.)
References in periodicals archive ?
Wozniak marveled at "the number of accidents in my life that led me to where I was," from teaming up with a friend to get covert access to an early computer room to run programs in the wee hours of the morning to how he learned about electronics from the first video game he saw--Pong.
The problem occurred because early computers had little storage or permanent memory capacity, so software programmers saved space by using only the last two digits of the year.
It would have been obvious to developers of early computers that allowances would have to be made for expanding the date fields in the future.
It was an Asian-American inventor, An Wang, who invented a component of the early computers and later founded his giant company.
These early computers could only perform simple functions, and weren't nearly as powerful or as easy to use as the computers we have today.
The output of early computers was directed to typewriter-like printers that responded to digital commands.
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