Short Code (computer language)
|Developer||William F Schmidt, A.B. Tonik, J.R. Logan|
|ENIAC Short Code|
|Intermediate programming language, OMNIBAC Symbolic Assembler|
Short Code was one of the first higher-level languages ever developed for an electronic computer. Unlike machine code, Short Code statements represented mathematic expressions rather than a machine instruction. Also known as an automatic programming, the source code was not compiled but executed through an interpreter to simplify the programming process; the execution time was much slower though.
Short Code was proposed by John Mauchly in 1949 and originally known as Brief Code. William Schmitt implemented a version of Brief Code in 1949 for the BINAC computer, though it was never debugged and tested. The following year Schmitt implemented a new version of Brief Code for the UNIVAC I where it was now known as Short Code (also Short Order Code). A revised version of Short Code was developed in 1952 for the Univac II by A. B. Tonik and J. R Logan.
While Short Code represented expressions, the representation itself was not direct and required a process of manual conversion. Elements of an expression were represented by two-character codes and then divided into 6-code groups in order to conform to the 12 byte words used by BINAC and Univac computers. For example the expression:
a = (b+c)/b*c
was converted to Short Code by a sequence of substitutions and a final regrouping:
X3 = ( X1 + Y1 ) / X1 * Y1 substitute variables X3 03 09 X1 07 Y1 02 04 X1 Y1 substitute operators and parentheses. Note multiplication is represented by juxtaposition. 07Y10204X1Y1 group into 12-byte words. 0000X30309X1
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- Schmitt, William F. The UNIVAC SHORT CODE. Annals of the History of Computing (1988) 10:pages 7-8
- Schmitt, William F. The UNIVAC SHORT CODE. Annals of the History of Computing (1988) 10:page 15
- Malik, Masud Ahmad. Evolution of the High Level Programming Languages: A Critical Perspective. ACM SIGPLAN Notices (December 1998) 33(12) page 74.
- Wexelblat, Richard L. (Ed.) (1981). History of Programming Languages, p. 9. New York: Academic Press. ISBN 0-12-745040-8
- Murdoch, Short Code (HOPL)