Editing A-0 System (section)

{{Short description|Programming language}}
The '''A-0 system''' (''Arithmetic Language version 0'') was an early<ref>{{cite web | title=List of early compilers and assemblers | url=http://shape-of-code.coding-guidelines.com/2017/05/21/evidence-for-28-possible-compilers-in-1957}}</ref> [[compiler]] related tool developed for electronic computers, written by [[Grace Hopper|Grace Murray Hopper]]<ref>{{cite book |last1=Ridgway|first1=Richard|title=Proceedings of the 1952 ACM national meeting (Toronto) on - ACM '52 |chapter=Compiling routines |date=1952|pages=1–5 |doi=10.1145/800259.808980 |isbn=9781450379250 |s2cid=14878552 |doi-access=free}}</ref> in 1951 and 1952 originally for the [[UNIVAC I]].<ref>Hopper "Keynote Address", Sammet pg. 12</ref> The A-0 functioned more as a [[Loader (computing)|loader]] or [[Linker (computing)|linker]] than the modern notion of a compiler.<ref>{{ cite conference |last=Hopper|first=Grace|title=Keynote Address|doi=10.1145/800025.1198341 |book-title=Proceedings of the ACM SIGPLAN History of Programming Languages (HOPL) conference, June 1978 | url=https://dl.acm.org/doi/pdf/10.1145/800025.1198341|url-access=subscription}}</ref><ref>{{ cite web |last=Bruderer|first=Herbert|title=Did Grace Hopper Create the First Compiler? | url=https://cacm.acm.org/blogs/blog-cacm/268001-did-grace-hopper-create-the-first-compiler/fulltext}}</ref><ref>{{cite journal |last1=Strawn |first1=George |last2=Strawn |first2=Candace |title=Grace Hopper: Compilers and Cobol | url = https://www.computer.org/csdl/magazine/it/2015/01/mit2015010062/13rRUxCitFF |journal=IT Professional |date=2015 |volume=17 |issue=Jan.-Feb. 2015 |pages=62–64 |doi=10.1109/MITP.2015.6 |url-access=subscription }} </ref> A program was specified as a sequence of subroutines and its arguments. The subroutines were identified by a numeric code and the arguments to the subroutines were written directly after each subroutine code. The A-0 system converted the specification into [[machine code]] that could be fed into the computer a second time to execute the said program.

The A-0 system was followed by the A-1, A-2,<ref>* {{cite journal |date=Sep 1955 |title=PAPERS: Automatic Programming: The A 2 Compiler System -- Part I |url=https://archive.org/details/sim_computers-and-people_1955-09_4_9/page/n24/ |journal=Computers and Automation |volume=4 |issue=9 |pages=25–29 |access-date=2020-09-05}}
* {{cite journal |date=Oct 1955 |title=PAPERS: Automatic Programming: The A 2 Compiler System -- Part II |url=https://archive.org/details/sim_computers-and-people_1955-10_4_10/page/15/ |journal=Computers and Automation |volume=4 |issue=10 |pages=15–27 |access-date=2020-09-05}}</ref> A-3 (released as [[ARITH-MATIC]]), AT-3 (released as [[MATH-MATIC]]), and B-0 (released as [[FLOW-MATIC]]).

The A-2 system was developed at the [[UNIVAC|UNIVAC division of Remington Rand]] in 1953 and released to customers by the end of that year.<ref>{{cite book | last=Ceruzzi | first=Paul | title=A History of Modern Computing | url=https://archive.org/details/historyofmodernc00ceru | url-access=registration | publisher=The MIT Press | date=1998 | isbn=9780262032551 }}</ref>  Customers were provided the source code for A-2 and invited to send their improvements back to UNIVAC. Thus, A-2 could be considered an example of the result of an early philosophy similar to [[free and open-source software]].<ref>{{cite web | title=Heresy & Heretical Open Source: A Heretic's Perspective | url=http://www.infoq.com/presentations/Heretical-Open-Source}}</ref>