Chapter 3 1952-1968.ppt

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1、Chapter 3 1952-1968,Early History of Software,Software,What is software? Programming? Extremes Microcode vs. Interface Read comments - Page 81 How did hw & sw fit together?,Summer 1944- Grace Hopper to Harvard Howard Aiken, MARK I Pg. 82 “Thus began the process of computer programming in the U.S.” I

2、dea for multiple tapes - for code reuse,Very Early Days,Early Programming,Mark III typed commands, stored on magnetic tape, executed (p83 pix) Zuse “Plan Preparation Machine” Commands on tape, check syntax, translated *Rutishauser Why separate device? EDSAC- library of paper tape code Wheeler Jump s

3、ubroutine call None stored in internal memory,Early Computers,UNIVAC 1952 Today translate to machine code Punch Cards: pre-punched + transitional = compile Grace Hopper: A-0 compiler at UNIVAC Automatic programming To handle subroutines by copying them into main Idea: “ Interchangeable parts” too in

4、flexible Realized were standardizing the wrong level of work,Whirlwind MIT,J.H. Laning & N. Zierler “A program for translation of mathematical equations for Whirlwind I” - 1954 Behaved like modern compilers Not general purpose - algebraic equations Backus (FORTRAN) Elegant but threatened the “priest

5、hood” Knuth too slow,Assemblers,Systems Programming Languages One-to-one binary (machine) code Macro instructions Symbolic Addressing (variables),SHARE,1955 - IBM 701 users in L.A. Compiled library of routines Grew to 62 members IBM responded to opinions Helped transition to 704,Sorting,Applications

6、 - Files on tape Up to 1973 - 25% compute time sorting People “used” printed reports, not computer Betty Holberton UNIVAC-1952 Sorted small groups and merged with master file Knuth “1st major software routine ever developed for automatic programming Later disks & linked lists - plus,FORTRAN - 1957,F

7、ormula Transistor- scientific IBM for 704, John Backus Still widely used Key to success: generated code as efficient as written code Fast; 704 had floating point hardware Combination of hiding and access,COBOL-1959,Common Business Oriented Language Dept. of Defense Produced language specifications U

8、.S. govt.: all h.w. must handle COBOL Thus, one of 1st standardized Grave Hopper UNIVAC Flow-matic - Use long character names Year 2000 bug Not really self documenting,Other Early Languages,ALGOL- Europe, 1958-1960 Hardware independent Specified in BNF JOVIAL Def. Dept. Variant of ALGOL for SAGE Sti

9、ll used recently LISP AI - Lists SNOBOL - Strings RPG IBM - still used AS400,Early System Software,Operator scheduled all resources Soon became too complex IBM - Job Control Language (JCL) What compiler data or code 1990s Operating System,MAD: Michigan Algorithmic Decoder,University students needed

10、“help” & needed efficient use of computers 1959: ALGOL Based *Fast Compile *Good Diagnostics Memory Dumps Helped to keep computer busy NOTE: No applications software!,Evolution of Operation Systems,Grew in complexity, size, consumption Monitor Supervisor system Operating system DOS to Windows (GUI)

11、IBM System/360-1966 OS/360- business + scientific - Failure,Mini-computers-1960s OS development started over Small memories VMS for VAX (DEC)-1978 Personal Computers OS development started over Again!,Computer Science,With Mathematics & Electrical Engineering Stanford and Purdue 1950s Stanford Georg

12、e Forsythe Mathematics 1961 Separate Dept. 1965 Study of computers vs. Study of Algorithms ACM Curriculum 68 (2013),Computer Science (cont.),1968 ACM Curriculum - no h.w. 1964 -12 University degrees 1968 - 100 1980 - Most popular major in the US,Donald Knuth- “The Art of Computer Programming”,1968 P

13、ublished 1st volume of 7 1: Fundamental Algorithms 2: Semi numerical Algorithms 3: Searching and Sorting,Knuth Cont.,TBA - in progress 4: Combinatorial Algorithms 5: Syntactic Algorithms Maybe - “God Willing” 6: Theory of Context free languages 7: Compiler Techniques www-cs-faculty.stanford.edu/Knut

14、h/taocp.html,Structured Programming,Edsger Dijkstra Tech. Univ. of Eindhoren, Neth. University of Texas March 1968 - CACM “For a number of years I have been familiar with the observation that the quality of programmers is decreasing function of the frequency of GOTO statements in the programs they p

15、roduce” Much Debate, but slow change,Intellectual Property,Letters in CACM, 1968 Rockford Inst., Calvin Mooers Sought legal protection for TRAC language No alterations, changes, etc. Bernard Galler, MAD, Michigan MAD & others had been improved by users TRAC failed - too early for protection Set stag

16、e for future laws/ lawsuits,Software Engineering,1968- NATO conference “Software Engineering” “Crisis” Programmers lacked “ theoretic foundations & disciplines of daily practice” from traditional engineering No certification nor chain of legal responsibility Continues to be debated SE Certification

17、in Texas,Unbundling,Separate H.W. and S.W. 1968 - IBM Government pressure CICS (Customer Info. Control System) Opened door for commercial vendors,UNIX,1969- Bell labs in N.J. Ken Thompson, Dennis Ritchie PDP-7 Language “B” “C” in 1973 Contrast to ALGOL68 & PL/1 Pascal- Nicholas Wirth, Sweden,Chapter 3 1952-1968,Early History of Software,