Editing PL/I (section)

==Standardization==
Language standardization began in April 1966 in Europe with [[European Computer Manufacturers Association|ECMA]] TC10. In 1969 [[American National Standards Institute|ANSI]] established a "Composite Language Development Committee", nicknamed "Kludge", later renamed X3J1 PL/I.<ref>Reacting to IBM's involvement, a number of manufacturers had been reluctant to endorse an effort on a Standard. The initial remit of CLDG/X3J1 was to investigate whether PL/I was a suitable candidate for standardization. The joint effort processed over 3500 proposals for language or textual changes.</ref> Standardization became a joint effort of ECMA TC/10 and ANSI X3J1. A subset of the GY33-6003<ref>"PL/I Language Specifications. GY33-6003"</ref> document was offered to the joint effort by IBM and became the base document for standardization. The major features omitted from the base document were [[Computer multitasking|multitasking]] and the attributes for [[program optimization]] (e.g., <code>NORMAL</code> and <code>ABNORMAL</code>).

Proposals to change the base document were voted upon by both committees. In the event that the committees disagreed, the chairs, initially Michael Marcotty of [[General Motors]] and [[C.A.R. Hoare]] representing [[International Computers Limited|ICL]] had to resolve the disagreement. In addition to IBM, [[Honeywell]], [[Control Data Corporation|CDC]], [[Data General]], [[Digital Equipment Corporation]], [[Prime Computer]], [[Burroughs Corporation|Burroughs]], [[RCA]], and [[Univac]] served on X3J1 along with major users [[Eastman Kodak]], [[MITRE]], [[Union Carbide]], [[Bell Laboratories]], and various government and university representatives. Further development of the language occurred in the standards bodies, with continuing improvements in structured programming and internal consistency, and with the omission of the more obscure or contentious features.

As language development neared an end, X3J1/TC10 realized that there were a number of problems with a document written in English text. Discussion of a single item might appear in multiple places which might or might not agree. It was difficult to determine if there were omissions as well as inconsistencies. Consequently, David Beech (IBM), Robert Freiburghouse (Honeywell), Milton Barber (CDC), M. Donald MacLaren ([[Argonne National Laboratory]]), Craig Franklin (Data General), Lois Frampton (Digital Equipment Corporation), and editor, D.J. Andrews of IBM undertook to rewrite the entire document, each producing one or more complete chapters. The standard is couched as a formal definition<ref name="ReferenceA"/>  using a "PL/I Machine"<ref>The PL/I machine defined in the standard is covered in [http://www.cs.yale.edu/publications/techreports/tr75.pdf ''The Definition Mechanism for Standard PL/I'']. Michael Marcotty, Frederick G Sayward.</ref>  to specify the semantics. It was the first programming language standard to be written as a semi-formal definition.

A "PL/I General-Purpose Subset" ("Subset-G") standard was issued by ANSI in 1981<ref name=SubsetG>ANSI X3.74-1981 (R1998) ''Information Systems - Programming Language - PL/I General-Purpose Subset''</ref> and a revision published in 1987.<ref>1987 PL/I General-Purpose Subset (ANSI X3.74-1987)</ref> The General Purpose subset was widely adopted as the kernel for PL/I implementations.