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A-0 System

programming language

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General referenceInterpretive dossier study · Crown Archives visual atlas
Record originEnglish Wikipedia
Text licenseCC BY-SA 4.0
Source revisionOct 16, 2025
Entity authorityQ277713 ↗
Source-derived summary

The A-0 system (Arithmetic Language version 0) was an early compiler-related tool developed for electronic computers, written by Grace Murray Hopper in 1951 and 1952 originally for the UNIVAC I. The A-0 functioned more as a loader or linker than the modern notion of a compiler. 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, 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 division of Remington Rand in 1953 and released to customers by the end of that year. 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.

See also

History of compiler construction

Notes

External links

Proceedings of the 1954 MIT Summer Session on "Digital Computers - Advanced Coding Techniques, section 7 - A2 Compiler and Associated Routines for use with Univac

References

Hopper, Grace (May 1952). "The Education of a Computer" (PDF). Proceedings of the Association for Computing Machinery Conference (Pittsburgh) May 1952.

Editorial summary

The public source identifies “A-0 System” as programming language. This brief keeps that definition visible, then builds a research path around System, programming and language.

Editorial reviewA dependable orientation record for establishing vocabulary, names and a first evidence trail. The current lead gives the account dated anchors—1951, 1952, 1953, 1954—that can be checked directly. The linked authority record independently contributes the date 1952. Its value is orientation rather than verdict, with System, programming and language providing the first useful test.
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Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Oct 16, 2025. The linked authority identifier is Q277713. 1 of 1 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank. The first chronological checks are 1951, 1952, 1953 and 1954.

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This entry incorporates text from “A-0 System” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.