Short Code (computer language)

This article is about the early computer language Short Code. For the use of this term in connection with telecommunications, see Short code.
Short Code
Developer William F Schmidt, A.B. Tonik, J.R. Logan
First appeared 1950 (1950)
Influenced by
ENIAC Short Code
Influenced
Intermediate programming language, OMNIBAC Symbolic Assembler

Short Code was one of the first higher-level languages ever developed for an electronic computer.[1] 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.[1]

History

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.[2]

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.[3] 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

Along with basic arithmetic, Short Code allowed for branching and calls to a library of functions. The language was interpreted and ran about 50 times slower than machine code.[4]

See also

References

  1. 1 2 Sebesta, W.S Concepts of Programming languages. 2006;M6 14:18 pp.44. ISBN 0-321-33025-0
  2. ↑ Schmitt, William F. The UNIVAC SHORT CODE. Annals of the History of Computing (1988) 10:pages 7-8
  3. ↑ Schmitt, William F. The UNIVAC SHORT CODE. Annals of the History of Computing (1988) 10:page 15
  4. ↑ Malik, Masud Ahmad. Evolution of the High Level Programming Languages: A Critical Perspective. ACM SIGPLAN Notices (December 1998) 33(12) page 74.
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