Ada

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Ada

The Ada language is the result of the most extensive and most expensive language design effort ever undertaken. The United States Department of Defense (DoD) was concerned in the 1970¡¦s by the number of different programming languages being used for its projects, some of which were proprietary and/or obsolete. Up until 1974, half of the applications at the DoD were embedded systems. An embedded system is one where the computer hardware is embedded in the device it controls. More than 450 programming languages were used to implement different DoD projects, and none of them were standardized. As a result of this, software was rarely reused. For these reasons, the Army, Navy, and Air Force proposed to develop a high-level language for embedded systems (The Ada Programming Language). In 1975 the Higher Order Language Working Group (HOLWG) was formed with the intent of reducing this number by finding or creating a programming language generally suitable for the department's requirements.

The working group created a series of language requirements documents - the Strawman, Tinman, and Ironman (and later Steelman) documents. Twenty-three existing languages were formally reviewed, FORTRAN, COBOL, PL/I, HAL/S, TACPOL, CMS-2, CS-4, SPL/I, JOVIAL J3, JOVIAL J73, ALGOL 60, ALGOL 68, CORAL 66, Pascal, SUMULA 67, LIS, LTR, TRL/2, EUCLID, PDL2, PEARL, MORAL, EL/I; but the team concluded in 1977 that no existing language met the specifications, though Pascal, ALGOL 68, or PL/I would be a good starting point (History of the Ada Programming Language). Requests for proposals for a new programming language were issued and four contractors were hired to develop their proposals under the names of Red, Green, Blue, and Yellow. In May of 1979, the Green proposal, designed by Jean Ichbiah at Cii Honeywell Bull, was chosen and given the name Ada, after Lady Ada Lovelace, the so-called first computer programmer. The reference manual was approved on December 10, 1980 (Ada Lovelace's birthday). The total number of high-level programming languages in use for embedded systems projects at the DoD fell from over 450 in 1983 to 37 by 1996. The DoD required the use Ada for every software project where new code was more than 30% of result, though exceptions to this rule were often granted. This requirement was effectively removed in 1997. Similar requirements existed in other North Atlantic Treaty Organization (NATO) countries.

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