1. Problems of Big Software - PowerPoint PPT Presentation

Obligatory Reading Balzert, Kapitel über Entscheidungstabellen ► Fakultät Informatik, Institut für Software- und Multimediatechnik, Lehrstuhl für Softwaretechnologie Ghezzi 6.3 Decision-table based testing ► Pfleeger 4.4, 5.6 ► Randal E. Bryant. Graph-based algorithms for Boolean function ► manipulation. IEEE Transactions on Computers, C-35:677-691, 1986. Ø Red Hat. JBoss Enterprise BRMS Platform 5: JBoss Rules 5 Reference Guide. (lots of examples for ECA Drools) 1. Problems of Big Software • http://docs.redhat.com/docs/en-US/JBoss_Enterprise_BRMS_Platform/5/pdf/ JBoss_Rules_5_Reference_Guide/JBoss_Enterprise_BRMS_Platform-5- JBoss_Rules_5_Reference_Guide-en-US.pdf Prof. Dr. rer. nat. habil. Uwe Aßmann Institut für Software- und Multimediatechnik Lehrstuhl Softwaretechnologie Fakultät für Informatik Technische Universität Dresden 2013-0.2, 12.10.13 Decision Analysis TU Dresden, Prof. U. Aßmann 2 Obligatory Literature Other Literature Balzert doesn’t contain much Ø S. Garfunkel: Die schönsten Software-Fehler ► http://www.wired.com/news/technology/bugs/0,2924,69355,00.html Ghezzi Chapter 1 or ► Ø Risks.org: www.risks.org Die Seite für Softwarefehler Pfleeger Chapter 1; Chap 8.1 ► http://homepages.cs.ncl.ac.uk/brian.randell/NATO/ ► The first International Conference on Software Engineering (ICSE) 1968. Problems of Big Software Problems of Big Software TU Dresden, Prof. U. Aßmann Folie TU Dresden, Prof. U. Aßmann Folie 3 von 27 4 von 27

What is “Big”? Big Systems Class Lines of Code Person years Telefone switching software Siemens EWSD (Version 8.1): ► 12,5 Mio. lines of code Very small <1000 <0.2 ■ ca. 6000 person years Small 1000 - 10000 0.2 - 2 ■ ERP-Software SAP R/3 (Version 4.0) ► Medium 10000 - 100000 2 - 20 ca. 50 Mio. lines of code ■ Large 100000 – 1 Mio 20 - 200 Total amount of lines of code in software (around 2000): ► Very large >1. Mio >200 Credit Suisse 25 Mio. Code-Zeilen ■ Chase Manhattan Bank: 200 Mio. Code-Zeilen ■ Citicorp Bank: 400 Mio. Code-Zeilen ■ AT&T: 500 Mio. Code-Zeilen ■ General Motors: 2 Mrd. Code-Zeilen ■ EWSD = Elektronisches Wählsystem Digital (Siemens) ERP = Enterprise Resource Planning SAP: Deutscher Software-Konzern Problems of Big Software Problems of Big Software TU Dresden, Prof. U. Aßmann Folie TU Dresden, Prof. U. Aßmann Folie 5 von 27 6 von 27 Collection of Software Bugs Software Bugs Ø Web site of Prof. Thomas Huckle Ø Peter G. Neumann http://www.risks.org The Risk Digest collects all possible software bugs Ø http://www5.in.tum.de/~huckle/bugse.html Mercedes console display with conflicting information <Henry Baker <hbaker1@pipeline.com>> Fri, 14 Dec 2007 10:48:39 -0800 The console display says "check engine" & "no malfunction" at the same time! Dueling messages! It is supposed to say "check engine" & "1 malfunction", if "check engine" is the only malfunction being reported. Problems of Big Software Problems of Big Software TU Dresden, Prof. U. Aßmann Folie TU Dresden, Prof. U. Aßmann Folie 7 von 27 8 von 27

The Industry Permanent Software Crisis? "Software Crisis": Top Players: IBM, Microsoft, HP, Hitachi, Computer Associates, Google, ► ► Oracle, SAP Errors in computer systems are mostly software faults ■ 2/3 standard software : 1/3 individual software (with growing rate) Software projects are often too late ► ■ Life Cycle of Software Software development costs too much ► ■ Average: 5 – 15y Software Crisist started in 1968, but exists still today ► ► max > 35 y (control software, certified systems, data bases) 70s: ► ■ Programmers die out ■ Modularity was disovered . Development time: 1 – 3y ► 90s, Millennium: ■ Much larger software systems . Massive testing necessary . We undoubtedly produce software by backward techniques. D. McIlroy, ICSE 1968 Problems of Big Software Problems of Big Software TU Dresden, Prof. U. Aßmann Folie TU Dresden, Prof. U. Aßmann Folie 9 von 27 10 von 27 Costs Cost Example: The Year 2000 Problem Contrary to Grosch’s Law, hardware speed doubles every 2 years, but COBOL programmers saved space and stored only the last two digits of ► ► software productivity increases only about < 5%/y the year In the 70s, programs should only live 20 years Costs ■ ► In 2000, catastrophes were prophesied acad. Prototype / acad. Product / Product = 1 : 3 : 3 ► ■ Commercialization is rather difficult Power plants? ■ ■ Relation of development and maintenance 40:60 up to 20:80 Pension insurances (birth dates) ► ■ From 1996 on, the industry panicked Development and maintenance are done by different departments ► ■ Costs: Extreme Requirements Spent enormous amounts to update software ► ■ New systems got installed Certification : show the software and its development process to a ► ■ certification agency (TÜV, etc.) SAP R/3 with date data type ■ Insurance: certified software must be executable after 40 years Rewriting didn’t work ■ ► Ex.: German pension rules of the 50s must be processed today . Programmers didn’t trust the rewrites ■ Nobody knows the details anymore . Solution: sliding window technique ■ Solution: write an interpreter for the old assembler . This has happened twice.. . Problems of Big Software Problems of Big Software TU Dresden, Prof. U. Aßmann Folie TU Dresden, Prof. U. Aßmann Folie 11 von 27 12 von 27

Cost Example: The Euro Introduction Cost Example: Telecommunication Telecommunication: Failure < 1 h./40 y., working rate 99.999% End of 2001, many countries introduced the Euro ► ■ One second failure may cost $5Mio Too bad: on paper, the Euro was introduced 2 years before . ► Some companies had to maintain double booking for 2 years Telecommunication software product line ■ ► At least for some months in 2002 20-30 000 Module of 1000 loc (lines of code) ■ ■ Double booking was very costly: accounts had to be printed in two currencies ■ Single product has 2-8000 modules ► How to test the transition? ► Necessary: 5000 persons/7years. ► In May 2001, the Dresdner bank ran a test ■ Costs ca. 7 billion € . Which failed,.. And produced many wrong money transfers! ► ■ Size of world market 50 billion € Many people worked day and night… ► ► How many suppliers can exist? ► Problems of Big Software Problems of Big Software TU Dresden, Prof. U. Aßmann Folie TU Dresden, Prof. U. Aßmann Folie 13 von 27 14 von 27 Human Problems History of the Term "Software-Engineering" Programmers are not educated well ► To develop ■ To communicate ■ Softwaretechnologie (Software-Engineering) Software construction is a social process ► Softwareingenieurswesen It’s hard to organize people ■ Softwaretechnik: Einzeltechnik aus der Lehre der Software stays, the people go ► Softwaretechnologie Software evolves, many versions ■ Projects run out of time ► How to control? ■ Programmer Productivity – Rules of Thumb ► software engineering: Die Entdeckung und Anwendung System software: 1000-2000 loc/y solider Ingenieur-Prinzipien mit dem Ziel, auf wirtschaftliche ► System like Software: 5000 loc/y Weise Software zu bekommen, die zuverlässig ist und auf ► Application software: 5-10000 loc/y realen Rechnern läuft. ► Master’s thesis: 10-20000 loc/thesis ► (F.L. Bauer, NATO-Konferenz Software-Engineering 1968) Individual differences up to factor 5 ► Has not changed in the last 30 years ■ Differences by programming language and reuse mechanisms ► Problems of Big Software Problems of Big Software TU Dresden, Prof. U. Aßmann Folie TU Dresden, Prof. U. Aßmann Folie 15 von 27 16 von 27