Editing PL/I (section)

===Multics PL/I and derivatives===
Compilers were implemented by several groups in the early 1960s. The [[Multics]] project at [[MIT]], one of the first to develop an operating system in a [[High-level programming language|high-level language]], used Early PL/I (EPL), a subset dialect of PL/I, as their implementation language in 1964. EPL was developed at [[Bell Labs]] and MIT by [[Douglas McIlroy]], [[Robert Morris (cryptographer)|Robert Morris]], and others.<ref name="MulticsPL1"/> Initially, it was developed using the [[TMG (language)|TMG]] compiler-compiler.<ref>{{cite web |editor=Tom Van Vleck |editor-link=Tom Van Vleck |url=https://multicians.org/pl1.html#EPL |title=The Choice of PL/I |website=Multicians.org}}</ref> The influential Multics PL/I compiler<ref name="MulticsPL1">{{cite web|url=http://www.multicians.org/pl1-raf.html|title=The Multics PL/1 Compiler|author=R. A. Frieburghouse|website=Multicians.org}}</ref> [sic "PL/1"] was the source of compiler technology used by a number of manufacturers and software groups. EPL was a system programming language and a dialect of PL/I that had some capabilities absent in the original PL/I.

The Honeywell PL/I compiler (for Series 60) is an implementation of the full ANSI X3J1 standard.<ref>{{cite book|publisher=[[Honeywell]]|title=Series 60 (Level 66)/6000 PL/I Reference Manual|id=Order No. DE05|year=1976}}</ref>