FLOW-MATIC

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FLOW-MATIC
Paradigm(s) imperative
Designed by Remington Rand, Grace Hopper
Appeared in 1955 (1955)
Influenced COBOL
Platform UNIVAC I

FLOW-MATIC, originally known as B-0 (Business Language version 0), was the first English-like data processing language. It was developed for the UNIVAC I at Remington Rand under Grace Hopper during the period from 1955 until 1959.

Development[edit]

Hopper had found that business data processing customers were uncomfortable with mathematical notation. In late 1953 she proposed that data processing problems should be expressed using English keywords, but Rand management considered the idea unfeasible. In early 1955, she and her team wrote a specification for such a programming language and implemented a prototype.[1] The FLOW-MATIC compiler became publicly available in early 1958 and was substantially complete in 1959.[2]

Innovations and Influence[edit]

First, FLOW-MATIC was the first programming language to express operations using English-like statements.[2]

Second, FLOW-MATIC was the first system to distinctly separate the description of data from the operations on it. Its data definition language, unlike its executable statements, was not English-like; rather, data structures were defined by filling in pre-printed forms.[2]

Flow-Matic was a major influence in the design of COBOL, since only it and its direct descendent AIMACO were in actual use at the time.[3] Several elements of Flow-Matic were incorporated into COBOL:

  • Defining files in advance, and separating into INPUT and OUTPUT files.
  • Qualification of data-names (IN or OF clause).
  • IF END OF DATA (AT END) clause on file READ operations.
  • Figurative constant ZERO (originally ZZZ...ZZZ, where number of Z's indicated precision).
  • Dividing the program into sections, separating different parts of the program. Flow-Matic sections included Computer (Environment Division), Directory (Data Division), and Compiler (Procedure Division).

Sample program[edit]

A sample FLOW-MATIC program:[4][5]

 (0)  INPUT INVENTORY FILE-A PRICE FILE-B ; OUTPUT PRICED-INV FILE-C UNPRICED-INV
     FILE-D ; HSP D .
 (1)  COMPARE PRODUCT-NO (A) WITH PRODUCT-NO (B) ; IF GREATER GO TO OPERATION 10 ;
     IF EQUAL GO TO OPERATION 5 ; OTHERWISE GO TO OPERATION 2 .
 (2)  TRANSFER A TO D .
 (3)  WRITE-ITEM D .
 (4)  JUMP TO OPERATION 8 .
 (5)  TRANSFER A TO C .
 (6)  MOVE UNIT-PRICE (B) TO UNIT-PRICE (C) .
 (7)  WRITE-ITEM C .
 (8)  READ-ITEM A ; IF END OF DATA GO TO OPERATION 14 .
 (9)  JUMP TO OPERATION 1 .
(10)  READ-ITEM B ; IF END OF DATA GO TO OPERATION 12 .
(11)  JUMP TO OPERATION 1 .
(12)  SET OPERATION 9 TO GO TO OPERATION 2 .
(13)  JUMP TO OPERATION 2 .
(14)  TEST PRODUCT-NO (B) AGAINST ZZZZZZZZZZZZ ; IF EQUAL GO TO OPERATION 16 ;
     OTHERWISE GO TO OPERATION 15 .
(15)  REWIND B .
(16)  CLOSE-OUT FILES C ; D .
(17)  STOP . (END)

Note that this sample includes only the executable statements of the program, the COMPILER section. The record fields PRODUCT-NO and UNIT-PRICE would have been defined in the DIRECTORY section, which did not use English-like syntax.[6]

Notes[edit]

  1. ^ Hopper (1978) p. 16.
  2. ^ a b c Sammet (1969) p. 316
  3. ^ Sammet (1978) p. 204.
  4. ^ Sperry Rand (1957) p. 7.
  5. ^ Sammet (1969) p. 323.
  6. ^ Hopper (1978) p. 18.

References[edit]

This article is based on material taken from the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the "relicensing" terms of the GFDL, version 1.3 or later.