Andrew Turley on The Relationship Between COBOL and Computer Science by Ben Schneiderman

by Papers_We_Love

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COBOL and Computer Science Andrew Turley (@casio_juarez) Papers We Love NYC April 12, 2017

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The paper ... “The Relationship Between COBOL and Computer Science” Ben Shneiderman Annals of the History of Computing ( Volume: 7, Issue: 4, Oct.-Dec. 1985 ) But also: “The Early History of COBOL” by Jean Sammet

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The Relationship Between COBOL And Comp Sci Relationship Status ... Computer Science COBOL

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The Relationship Between COBOL And Comp Sci Shneiderman presents three perspectives ● Historical ● Technical ● Social/Psychological

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History

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History -- April 1959 At a meeting of “computer people” at the University of Pennsylvania Computer Center there is a discussion of the need for a “machine independent common language”

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History -- May 1959 Meeting held at the Pentagon to discuss the need for a common business language About 40 participants: ● 15 from government ● 11 users and consultants ● 15 representatives of manufacturers

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History -- May 1959 (continued) Three committees were created to develop a programming language (executive, short-range, long-range) with members from … ● David Taylor Model Basin ● Sylvania Electric Products ● Sperry Rand ● US Steel ● DuPont ● Air Materiel Command ● NCR ● USA - Signal Corps ADPS School ● National Bureau of Standards ● Department of the Navy ● IBM ● US Air Force ● Honeywell ● RCA ● Burroughs

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History -- June - December 1959 The short-range committee explores language options “to recommend a short-range composite approach (good for at least the next year or two)”

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History -- June - December 1959 “It was definitely felt that the Intermediate-Range Committee would have the time and resources to develop a really good business data processing language.” -- Sammet

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History -- June - December 1959 “I am certainly convinced in my own mind that had the Short-Range Committee realized at the outset that the language it created was going to be in use for such a long period of time, it would have gone about the task quite differently.” -- Sammet

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History -- December 1960 Same program runs on two different computers. First real cross-platform language!

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History -- August 1961 “COBOL: A Sample Problem” appears in Communications of the ACM 7 pages long: ● 2.5 pages of flow charts ● 3 pages of code ● 0 references

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History -- May 1962 Communications of the ACM issue dedicated to COBOL ● 13 articles about COBOL ● Only 4 have references

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Technology

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Technology Goals:

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Technology Goals: ● Solve business problems EMPLOYEES.DAT JOHN SMITH 13 SALLY JONES 42 ROCK MANLY 42 ... PROJECTS.DAT DEATH-RAY 13 SHARK-BOMB 42 KITTEN-TOES 78 ... PROJECT-HEADCOUNT.DAT DEATH-RAY 01 SHARK-BOMB 02 KITTEN-TOES 00 ... CREATE- PROJECT- HEADCOUNT. CBL

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Technology Goals: ● Solve business problems ● Cross-platform (“common”) PROGRAM.CBL OUTPUT.DAT

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Technology Goals: ● Solve business problems ● Cross-platform (“common”) ● English-like language PERFORM REPORT-GENERATION UNTIL END-SAMPLE-DATA.

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Technology Goals: ● Solve business problems ● Cross-platform (“common”) ● English-like language ● Verb-base language, “few verbs with many options rather than a large number of verbs with a few options”

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Technology COBOL program ● Divisions (IDENTIFICATION, ENVIRONMENT, DATA, PROCEDURE) ○ Sections ■ Paragraphs ● Sentences ○ Statements

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Technology IDENTIFICATION DIVISION. * program name ENVIRONMENT DIVISION. * environment-dependent stuff DATA DIVISION. * define record (data) structure PROCEDURE DIVISION. * define operations

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Technology IDENTIFICATION DIVISION. * program name ENVIRONMENT DIVISION. * environment-dependent stuff DATA DIVISION. * define record (data) structure PROCEDURE DIVISION. * define operations ENVIRONMENT DIVISION. INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT SAMPLE-FILE ASSIGN TO "S.DAT" ORGANIZATION IS LINE SEQUENTIAL.

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Technology IDENTIFICATION DIVISION. * program name ENVIRONMENT DIVISION. * environment-dependent stuff DATA DIVISION. * define record (data) structure PROCEDURE DIVISION. * define operations DATA DIVISION. FILE SECTION. FD SAMPLE-FILE. 01 SAMPLE-DATA. 88 END-SAMPLE-DATA VALUE HIGH-VALUES. 02 SAMPLE-NAME. 03 FIRST-NAME PIC X(8). 03 LAST-NAME PIC X(8). 02 DATE-OF-BIRTH. 03 YOB PIC 9(4). 03 MOB PIC 9(2). 03 DOB PIC 9(2). WORKING-STORAGE SECTION. 01 GENERATION PIC X(10). 01 BOOMER PIC X(10) VALUE "boomer". 01 GEN-X PIC X(10) VALUE "gen X". 01 MILLENNIAL PIC X(10) VALUE "millennial". 01 UNKNOWN PIC X(10) VALUE "???". * define record (data) structure Input Record Format (SAMPLE-DATA): |_ _ _ _ _ _ _ _|_ _ _ _ _ _ _|_ _ _ _|_ _|_ _| | FIRST-NAME | LAST-NAME | YOB |MOB|DOB| | SAMPLE-NAME | DATE-OF-BIRTH | | SAMPLE-DATA |

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Technology IDENTIFICATION DIVISION. * program name ENVIRONMENT DIVISION. * environment-dependent stuff DATA DIVISION. * define record (data) structure PROCEDURE DIVISION. * define operations PROCEDURE DIVISION. BEGIN. OPEN INPUT SAMPLE-FILE. READ SAMPLE-FILE AT END SET END-SAMPLE-DATA TO TRUE. PERFORM REPORT-GENERATION UNTIL END-SAMPLE-DATA. CLOSE SAMPLE-FILE. STOP RUN. REPORT-GENERATION. IF YOB >= 1980 SET GENERATION TO MILLENNIAL ELSE IF YOB >= 1946 AND YOB < 1965 SET GENERATION TO BOOMER ELSE IF YOB >= 1965 AND YOB < 1980 SET GENERATION TO GEN-X ELSE SET GENERATION TO UNKNOWN. DISPLAY FIRST-NAME SPACE LAST-NAME SPACE GENERATION. READ SAMPLE-FILE AT END SET END-SAMPLE-DATA TO TRUE. Input Record Format (SAMPLE-DATA): |_ _ _ _ _ _ _ _|_ _ _ _ _ _ _|_ _ _ _|_ _|_ _| | FIRST-NAME | LAST-NAME | YOB |MOB|DOB| John Smith 19500210 Stacy Jones 19781015 Kendra Manning 19840323

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Technology IDENTIFICATION DIVISION. * program name ENVIRONMENT DIVISION. * machine-dependent stuff DATA DIVISION. * define record (data) structure PROCEDURE DIVISION. * define operations PROCEDURE DIVISION. BEGIN. OPEN INPUT SAMPLE-FILE. READ SAMPLE-FILE AT END SET END-SAMPLE-DATA TO TRUE. PERFORM REPORT-GENERATION UNTIL END-SAMPLE-DATA. CLOSE SAMPLE-FILE. STOP RUN. REPORT-GENERATION. IF YOB >= 1980 SET GENERATION TO MILLENNIAL ELSE IF YOB >= 1946 AND YOB < 1965 SET GENERATION TO BOOMER ELSE IF YOB >= 1965 AND YOB < 1980 SET GENERATION TO GEN-X ELSE SET GENERATION TO UNKNOWN. DISPLAY FIRST-NAME SPACE LAST-NAME SPACE GENERATION. READ SAMPLE-FILE AT END SET END-SAMPLE-DATA TO TRUE. Paragraphs Significant whitespace

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Technology At first there was only one string processing command (INSPECT) and it was pretty weak

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Technology Every sentence could end with “AND GO TO …”

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Technology No local variables, no real procedure calls

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Psychology

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Psychology Data processing was not seen as an interesting problem

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Psychology Professors were not interested in running “trade schools”

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Psychology English seemed “unscientific”

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Conclusions

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Conclusions COBOL ignored academic computer science (for better or worse)

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Conclusions COBOL was widely adopted and used

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Conclusions COBOL was a flawed language

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Thanks! Further Reading ● “The Relationship Between COBOL and Computer Science” Ben Shneiderman ● “The Early History of COBOL” Jean Sammet ● “Learning To Program In Structured COBOL: Parts 1 & 2” Yourdon et al ● Communications of the ACM, May 1962 ● Micro Focus (microfocus.com) -- Go to a COBOL Dev Day!

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A Brief Introduction to COBOL

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A Brief Introduction to COBOL COmmon → write once, run anywhere! Business Oriented → record processing, extract-transform-load (ETL) Language → English-like syntax (verbs, nouns, sentences, paragraphs)

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A Brief Introduction to COBOL -- Code IDENTIFICATION DIVISION. * program name ENVIRONMENT DIVISION. * machine-dependent stuff DATA DIVISION. * define record (data) structure PROCEDURE DIVISION. * define operations ENVIRONMENT DIVISION. INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT SAMPLE-FILE ASSIGN TO "S.DAT" ORGANIZATION IS LINE SEQUENTIAL.

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A Brief Introduction to COBOL -- Code IDENTIFICATION DIVISION. * program name ENVIRONMENT DIVISION. * machine-dependent stuff DATA DIVISION. * define record (data) structure PROCEDURE DIVISION. * define operations DATA DIVISION. FILE SECTION. FD SAMPLE-FILE. 01 SAMPLE-DATA. 88 END-SAMPLE-DATA VALUE HIGH-VALUES. 02 SAMPLE-NAME. 03 FIRST-NAME PIC X(8). 03 LAST-NAME PIC X(8). 02 DATE-OF-BIRTH. 03 YOB PIC 9(4). 03 MOB PIC 9(2). 03 DOB PIC 9(2). WORKING-STORAGE SECTION. 01 GENERATION PIC X(10). 01 BOOMER PIC X(10) VALUE "boomer". 01 GEN-X PIC X(10) VALUE "gen X". 01 MILLENNIAL PIC X(10) VALUE "millennial". 01 UNKNOWN PIC X(10) VALUE "???". * define record (data) structure Input Record Format (SAMPLE-DATA): |_ _ _ _ _ _ _ _|_ _ _ _ _ _ _|_ _ _ _|_ _|_ _| | FIRST-NAME | LAST-NAME | YOB |MOB|DOB| | SAMPLE-NAME | DATE-OF-BIRTH | | SAMPLE-DATA |

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A Brief Introduction to COBOL -- Code IDENTIFICATION DIVISION. * program name ENVIRONMENT DIVISION. * machine-dependent stuff DATA DIVISION. * define record (data) structure PROCEDURE DIVISION. * define operations PROCEDURE DIVISION. BEGIN. OPEN INPUT SAMPLE-FILE. READ SAMPLE-FILE AT END SET END-SAMPLE-DATA TO TRUE. PERFORM REPORT-GENERATION UNTIL END-SAMPLE-DATA. CLOSE SAMPLE-FILE. STOP RUN. REPORT-GENERATION. SET GENERATION TO UNKNOWN. IF YOB >= 1980 SET GENERATION TO MILLENNIAL ELSE IF YOB >= 1946 AND YOB < 1965 SET GENERATION TO BOOMER ELSE IF YOB >= 1965 AND YOB < 1980 SET GENERATION TO GEN-X. DISPLAY FIRST-NAME SPACE LAST-NAME SPACE GENERATION. READ SAMPLE-FILE AT END SET END-SAMPLE-DATA TO TRUE.

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A Brief Introduction to COBOL -- Historical Position Steve Russell writes the first implementation of LISP → (early? late?) 1959 Discussion of developing “a problem-oriented but machine independent common language for business problems” → UPenn April, 1959 “Recursive Functions of Symbolic Expressions And Their Computation By Machine” → CACM April, 1960 “Essentially the same COBOL program was run on [two computers]” → December 1960 “COBOL: a sample problem” → CACM August, 1961 The COBOL issue → CACM May, 1962

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A Brief Introduction to COBOL -- Assumptions Technical ● business users want to read records from files, process them, and write new records to other files ● records have a fixed number of fixed-size fields ● files are generally stored on separate storage media (like tapes) Non-Technical ● “managers” (non-technical people) should be able to read and write code ● making a programming language similar to a “real” language will make it easier to read and write ● mathematical notation is off-putting

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“The Relationship Between COBOL and Computer Science” Ben Shneiderman, 1985

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The Relationship Between COBOL and Comp Sci “For a computer scientist to write sympathetically about COBOL is an act bordering on heresy.” Historical Perspective Technical Perspective Social/Psychological Perspective

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Historical Perspective

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Historical Perspective “academic computer scientists did not participate in the design team”

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Historical Perspective “academic computer scientists did not participate in the design team” COBOL contributors came from: US Air Force Honeywell RCA Burroughs Corporation David Taylor Model Basin Sylvania Electric Products IBM Speary Rand Bureau of Ships US Steel Corporation DuPont Company Air Materiel Command NCR USA - Signal Corps

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Historical Perspective “the COBOL developers apparently had little interest in the academic or scientific aspects of their work”

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Historical Perspective “the COBOL developers apparently had little interest in the academic or scientific aspects of their work” CACM of May 1962 was dedicated to COBOL, only four papers had any references. But … “Thus, of 15 papers presented at an Office of Naval Research (ONR) symposium on automatic programming for digital computers in May 1954 [2], only two have separate acknowledgements and none refers to other papers.” -- Backus, “Programming in America in the 1950s- Some Personal Impressions”

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Historical Perspective “the decision of the developers to not use the Backus-Naur Form notation as the metalanguage to describe COBOL”

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Historical Perspective “the decision of the developers to not use the Backus-Naur Form notation as the metalanguage to describe COBOL” COBOL Committee invented their own specification language

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Historical Perspective “the decision of the developers to not use the Backus-Naur Form notation as the metalanguage to describe COBOL” COBOL Committee invented their own specification language BNF first used to describe ALGOL 60 “Specification Languages for Mechanical Languages And Their Processors …” includes BNF, along with others → Gorn, ACM December, 1961

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Historical Perspective “A fourth concern is the process of describing COBOL to the academic and industrial community”

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Historical Perspective “A fourth concern is the process of describing COBOL to the academic and industrial community” Translation: For a long time there were no good books “emphasizing the conceptual foundations of COBOL”

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Historical Perspective “the people who might have accepted the title of computer scientist in 1960 were not interested in the problem domain of COBOL programs”

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Historical Perspective “the people who might have accepted the title of computer scientist in 1960 were not interested in the problem domain of COBOL programs” COBOL was good at: ● data processing Computer scientists were interested in: ● numerical analysis ● physics ● engineering ● systems programming

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Technical Perspective Successes

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Technical Perspectives - Successes Record Structure ● aggregation of dissimilar items ● hierarchy of names for fields DATA DIVISION. FILE SECTION. FD SAMPLE-FILE. 01 SAMPLE-DATA. 88 END-SAMPLE-DATA VALUE HIGH-VALUES. 02 SAMPLE-NAME. 03 FIRST-NAME PIC X(8). 03 LAST-NAME PIC X(8). 02 DATE-OF-BIRTH. 03 YOB PIC 9(4). 03 MOB PIC 9(2). 03 DOB PIC 9(2). WORKING-STORAGE SECTION. 01 GENERATION PIC X(10). 01 BOOMER PIC X(10) VALUE "boomer". 01 GEN-X PIC X(10) VALUE "gen X". 01 MILLENNIAL PIC X(10) VALUE "millennial". 01 UNKNOWN PIC X(10) VALUE "???". * define record (data) structure Input Record Format (SAMPLE-DATA): |_ _ _ _ _ _ _ _|_ _ _ _ _ _ _|_ _ _ _|_ _|_ _| | FIRST-NAME | LAST-NAME | YOB |MOB|DOB| | SAMPLE-NAME | DATE-OF-BIRTH | | SAMPLE-DATA |

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Technical Perspectives - Successes “[S]eparation of data definition from procedural aspects” IDENTIFICATION DIVISION. * program name ENVIRONMENT DIVISION. * machine-dependent stuff DATA DIVISION. * define record (data) structure PROCEDURE DIVISION. * define operations

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Technical Perspectives - Successes Diverse set of control structures ● IF-THEN-ELSE ● PERFORM

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Technical Perspectives - Successes COPY keyword (kind of like “include”, copied content of a file into a program) ● organizational standards were easily enforced ● improved cooperation ● encouraged code reuse

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Technical Perspectives - Successes ENVIRONMENT Division ● specify machine or compiler dependencies

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Technical Perspectives - Successes Portability and standardization ● first truly cross-platform language

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Technical Perspective Failures

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Technical Perspectives - Failures No local variables ● required careful coordination of collaborators ● in 1974 CALL-USING was added, permitted parameters and runtime creation of procedure names

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Technical Perspectives - Failures English-like languages ● supposed to be readable by managers ● “too wordy”, “somehow unscientific”

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Technical Perspectives - Failures Poor control flow readability ● originally, IF blocks were terminated with a period (“.”), which was easily missed when reading code PROCEDURE DIVISION. BEGIN. OPEN INPUT SAMPLE-FILE. READ SAMPLE-FILE AT END SET END-SAMPLE-DATA TO TRUE. PERFORM REPORT-GENERATION UNTIL END-SAMPLE-DATA. CLOSE SAMPLE-FILE. STOP RUN. REPORT-GENERATION. SET GENERATION TO UNKNOWN. IF YOB >= 1980 SET GENERATION TO MILLENNIAL ELSE IF YOB >= 1946 AND YOB < 1965 SET GENERATION TO BOOMER ELSE IF YOB >= 1965 AND YOB < 1980 SET GENERATION TO GEN-X. DISPLAY FIRST-NAME SPACE LAST-NAME SPACE GENERATION. READ SAMPLE-FILE AT END SET END-SAMPLE-DATA TO TRUE.

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Technical Perspectives - Failures Poor string handling ● EXAMINE, TALLYING, REPLACING ● in 1974 added INSPECT, STRING, UNSTRING

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Social/Psychological Perspective

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Social/Psychological Perspective “fundamental differences between the computer science and business data processing communities”

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Social/Psychological Perspective “fundamental differences between the computer science and business data processing communities” ● dismissed the complexity of the problem of data processing

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Social/Psychological Perspective “fundamental differences between the computer science and business data processing communities” ● dismissed the complexity of the problem of data processing ● had difficulty describing data processing problems with their theories