AdaThe Ada language is the result of the most extensive and expensive language design effort ever undertaken. In the 1970s the United States Department of Defense (DoD) was concerned about the number of different programming languages ​​used for its projects, some of which were proprietary and/or obsolete. Until 1974, half of the Department of Defense's applications were embedded systems. An embedded system is one in which the computer hardware is incorporated into 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, the software was rarely reused. For these reasons, the Army, Navy and Air Force have proposed developing 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 suited to the department's requirements. The working group created a series of language requirements documents: Strawman, Tinman, and Ironman (and later Steelman) documents. Twenty-three existing languages ​​were formally revised: 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, EUCLIDE, PDL2, PERLA, MORALE, EL/I; but the group concluded in 1977 that no existing language met the specification, although Pascal, ALGOL 68, or PL/I would have been a good place to start (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 Red, Green, Blue, and Yellow. In May 1979, Proposal Green, designed by Jean Ichbiah at Cii Honeywell Bull, was chosen and named 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 Department of Defense dropped from over 450 in 1983 to 37 in 1996. The Department of Defense required the use of Ada for every software project in where the new code accounted for more than 30% of the result, although 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)..