Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 1 Informatics 43 Introduction to Software Engineering Lecture 5-2 April 30, 2015 Emily Navarro Duplication of course material for any commercial purpose without the explicit written permission of the professor is prohibited.

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 2 Today’s lecture Reminders Software Process Models – Build-and-fix – Waterfall – Rapid Prototyping – Incremental Homework 2 Midterm study guide

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 3 Today’s lecture Reminders Software Process Models – Build-and-fix – Waterfall – Rapid Prototyping – Incremental Homework 2 Midterm study guide

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 4 Reminder: Essential Ingredients of Software Engineering People – who else would do the work? – range from novice to very experienced Processes – to organize and manage the efforts of individuals – range from informal to very formal Tools – to support the people and the processes – range from simple to very advanced

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 5 Reminder: Processes Essential to achieve a quality product Scarce resource – quality – suitability – cost Many different kinds of processes – bug tracking – change approval – quality assurance Instructor Reminder: Play first “process” video:

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 6 High Cost

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 7 Cost of Change Progressively Higher

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 8 More Reminders Essential qualities – Complexity – Conformity – Changeability – Intangibility Potentially drastic or disastrous consequences

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 9 Today’s lecture Reminders Software Process Models – Build-and-fix – Waterfall – Rapid Prototyping – Incremental Homework 2 Midterm study guide

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 10 Processes as a Remedy Software is engineered via a defined process – Cover all steps from initial idea and requirements to delivery, maintenance, and final retirement – Make sure we do the right things/we do things right – Make sure we do not forget to do anything – Different processes for different kinds of software Not a silver bullet [Brooks “No Silver Bullet”] – Software is still intrinsically difficult to deal with – Processes help, but cannot guarantee anything Remember: People + Processes + Tools  Product

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 11 Processes Elements – Activities (“Phases”) – Artifacts E.g., requirements document, design document, code, test cases… Can include process specifications – Resources People (their time and their cost) Tools (their time and their cost) Relationships between the elements – Precedence, requires, provides, refines to, … Constraints – Time – Cost – Qualities (repeatable process?)

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 12 Fun with Models Fashion Student

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 13 Fun with Models Fashion Student Model = Ideal

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 14 Fun with Models Software Process Model Waterfall Prototype Spiral Architecture Model Layered Client Server Model View Controller Model = Simplified Representation

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 15 Fun with Models public class Elephant { int weight; // in kg String name; Species species; public void forage() {.... } Model = Simplified Representation

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 16 What is Software Process Model for? A software process model can be thought of – “prescriptively” – enforcing rules – or “descriptively” – serving to describe or characterize

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 17 Software Life Cycle Models Build-and-fix Waterfall Rapid prototyping Incremental Spiral Rational Unified Process (RUP) Open Source Software (OSS) Extreme Programming (XP) Agile A software life cycle model is a high-level process

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 18 Today’s Lecture Reminders Software Process Models – Build-and-fix – Waterfall – Rapid Prototyping – Incremental Homework 2 Midterm study guide

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 19 Build-and-Fix Build first version Modify until client is satisfied Operations mode Retirement Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 20 Build-and-Fix Build first version Modify until client is satisfied Operations mode Retirement Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 21 Build-and-Fix Build first version Modify until client is satisfied Operations mode Retirement Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 22 Build-and-Fix Build first version Modify until client is satisfied Operations mode Retirement Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 23 Build-and-Fix Build first version Modify until client is satisfied Operations mode Retirement Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 24 Build-and-Fix Build first version Modify until client is satisfied Operations mode Retirement Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 25 So… What is it good for? (strengths) What is it bad for? (weaknesses)

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 26 So… What is it good for? (strengths) – Small programs that do not require much maintenance What is it bad for? (weaknesses)

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 27 So… What is it good for? (strengths) – Small programs that do not require much maintenance What is it bad for? (weaknesses) – Any nontrivial project

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 28 Today’s Lecture Reminders Software Process Models – Build-and-fix – Waterfall – Rapid Prototyping – Incremental Homework 2 Midterm study guide

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 29 Waterfall First documented by Royce in 1970 (!) Has withstood the test of time – Still being used worldwide… – But not without problems…

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 30 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 31 Waterfall Has clear benefits/strengths – “Forced” discipline (rigor/formality) Stepwise progression through well-defined phases Documentation-driven at each phase Each phase ends with Testing/Quality Assurance – Validation, verification, and the ability to correct – Feedback loops During product development Post-delivery maintenance So… – What seems to be the problem(s)?

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 32 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 33 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 34 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 35 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 36 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 37 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 38 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 39 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 40 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 41 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 42 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 43 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 44 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 45 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 46 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 47 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 48 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 49 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 50 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 51 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 52 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 53 Waterfall Operations mode Retirement Requirements phase Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 54 So… What is it good for? (strengths) What is it bad for? (weaknesses)

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 55 So… What is it good for? (strengths) – Promotes understanding of requirements first – Disciplined – Lots of documentation – Easy to track progress – Provides a framework upon which to create more dynamic, realistic processes – Good for short, simple projects will well-understood requirements What is it bad for? (weaknesses)

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 56 So… What is it good for? (strengths) – Promotes understanding of requirements first – Disciplined – Lots of documentation – Easy to track progress – Provides a framework upon which to create more dynamic, realistic processes – Good for short, simple projects will well-understood requirements What is it bad for? (weaknesses) – No iterations – Limited user input – Bad for long-term projects with any ambiguity in requirements

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 57 Today’s Lecture Reminders Software Process Models – Build-and-fix – Waterfall – Rapid Prototyping – Incremental Homework 2 Midterm study guide

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 58 Rapid Prototyping Operations mode Retirement Build and discard simple prototype Verify Specification phase Verify Design phase Verify Implementation phase Test Integration phase Test Changed requirements Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 59 Today’s Lecture Reminders Software Process Models – Build-and-fix – Waterfall – Rapid Prototyping – Incremental Homework 2 Midterm study guide

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 60 FOR EACH BUILD Perform detailed design, implementation, and integration. Test. Deliver to client. Incremental Operations mode Retirement Requirements phase Verify Specification phase Verify Architectural design Verify Development Maintenance

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 61 Today’s Lecture Reminders Software Process Models – Build-and-fix – Waterfall – Rapid Prototyping – Incremental Homework 2 Midterm study guide

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 62 Looking forward to homework 2 Multi-person – What if people “step on each other’s toes?” – What if people need to access each other’s files? Multi-version – Each version has some shared files, and some files specific to that version – Versions may replace each other over time – A prior version may need to be examined or modified

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 63 Version Control Software a.k.a. “Revision control,” “Source control” Manages changes over time by multiple people Tension between safety and flexibility, between control and freedom

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 64 Homework 2 Homework 2 will introduce you to the concepts and software behind version control, using the example of Git Three parts – Part A (due 5/12) Install Git Perform some basic commands – Part B (due 5/19) Create a local repository – Part C (due 5/26) Download and examine a public repository

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 65 Homework 2 Homework 2 is posted For technical help/questions with the assignment, post on Piazza Attend discussion tomorrow for an introduction to Git

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 66 Today’s Lecture Reminders Software Process Models – Build-and-fix – Waterfall – Rapid Prototyping – Incremental Homework 2 Midterm study guide

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 67 Midterm Next Thursday, May 7 th 80 minutes long Closed book, closed notes You can leave when you are finished Show your ID card to one of the teaching staff Exit only through the two doors at the bottom of the classroom Part multiple-choice, part short/long answer Advice: read questions carefully, re-read your answer and check whether it clearly says what you mean, don’t rush out at the end

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 68 Midterm Topics The two Brooks articles Software process models (through today’s lecture) – Waterfall model + strengths/weaknesses – Rapid prototyping and incremental models Requirements engineering Software qualities (security, usability, etc.) Software failures Software engineering big picture (definition, perspectives, essential ingredients, characteristics, principles) – Know one definition of SE word-for-word Use cases Software architecture, architectural styles, architectural evolution Anything else from lecture

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 69 Midterm Studying Lectures Things I told you to study for quizzes Quizzes Discussion assignments

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 70 Midterm Studying On the Unix or Linux command line, you can start with a file of records, then filter them, sort them, and remove duplicate records. This architectural style is called Filter-and-pipe Publish-subscribe Pipe-and-filter Layered None of the above Draw and label a diagram of the pipe-and-filter architectural style. Describe one of its benefits.

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 71 Midterm Studying The incremental software process model is a variation of: The Spiral model The Waterfall model Extreme Programming Rational Unified Process Describe how the Incremental software process model improves upon the Waterfall model.

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 72 Midterm Questions

Department of Informatics, UC Irvine SDCL Collaboration Laboratory Software Design and sdcl.ics.uci.edu 73 Next time More software process models