|Developer||William F Schmitt, 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 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 that multiplication is represented by juxtaposition. 07Y10204X1Y1 group into 12-byte words. 0000X30309X1
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