1 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Lecture 1 Overview of Software Life Cycle & Software Engineering Paradigms

2 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 What is Software? Software is a set of items or objects that form a “configuration” that includes programs documents data...

3 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 What is Software?  software is engineered  software doesn’t wear out  software is complex  software is a ‘differentiator’  software is like an ‘aging factory’

4 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Software Applications  system software  real-time software  business software  engineering/scientific software  embedded software  PC software  AI software  Web applications

5 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Wear vs. Deterioration idealized curve Failure rate Time rate due to side effects change actual curve increased failure

6 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 The Cost of Change

7 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Software Poses Challenges

8 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Problem Solving Approach  Analyzing the problem  Break the problem down into sub-problems  Construction of solutions  Formation of solution to sub-problems  Synthesis of the complete solution from sub-solutions Solution Methods / Techniques, e.g. chef prepare sauce Tools, e.g. typewriter Procedures, e.g. recipe Paradigm, e.g. a cooking style

9 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Problem Solving  Methods/Technique  A formal procedure for producing some result  Tools  An instrument for accomplishing something in a better way  Procedure  A combination of tools and techniques that, in conjunction, produce a particular product  Paradigm  A particular approach or philosophy for building software

10 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Software Quality  Perspectives on Quality (Gavin (1984))  the transcendental view, where quality is something we can recognize but not define  the user view, where quality is fitness of purpose  the manufacturing view, where quality is conformance to specification  the product view, where quality is tied to inherent product characteristics  the value-based view, where quality depends on the amount the customer is willing to pay for it

11 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Dimenstion of Quality  Quality of the Product  User - Does the job? A lot of Failure?  IT people – number & types of faults  c.f. McCall’s quality model (to be continued…)  Quality of the Process  Quality of the development and maintenance process is important  Can be examined and improved  c.f. CMM (tbc …)  Quality in the Context of the Business Environment  Return on investment

12 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Software Engineering A Layered Technology Software Engineering a “quality” focus process model methods tools

13 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 A Common Process Framework Common process framework Framework activities work tasks work products milestones & deliverables QA checkpoints Umbrella Activities

14 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Umbrella Activities  Software project management  Formal technical reviews  Software quality assurance  Software configuration management  Document preparation and production  Reusability management  Measurement  Risk management

15 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Process as Problem Solving

16 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 The Process Model: Adaptability  the framework activities will always be applied on every project... BUT  the tasks (and degree of rigor) for each activity will vary based on:  the type of project (an “entry point” to the model)  characteristics of the project  common sense judgment; concurrence of the project team

17 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 The Primary Goal: High Quality Remember: High quality = project timeliness Why? Less rework!

18 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Software Life Cycle  Requirements analysis and definition  System design  Program design  Program development/implementation  Unit testing  Integration testing  System testing  System delivery  Maintenance/Support

19 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 The Linear/Waterfall Model analysis designcodetest System/information engineering Too rigid – can’t cope with changes Doesn’t reflect reality

20 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Iterative Models (1) Prototyping RAD Present ‘false’ impression May contain implementation compromises

21 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Waterfall Model with Prototyping analysis designcodetest engineering Prototype Validate Verify System/information

22 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 V Model analysis design code test Support Validate requirement Verify design

23 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Iterative Models (2) Prototyping RAD Large human resources requirement Requirement full commitment of all parties Not applicable to non-modularizable or high risk projects

24 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 The Incremental Model

25 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Iterative vs. Incremental Model Incremental Model Iterative Model

26 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 An Evolutionary (Spiral) Model Concept development New Product development Product Enhancement Product Maintenance

27 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 WINWIN Spiral Model 1.Identify next-level stakeholders 2.Identify stakeholders’ win conditions Life cycle objectives (LCO) 3.(a) Reconcile win conditions (b) Establish next-level objectives, constraints and alternatives Life cycle architecture (LCA) 4.Evaluate process and product alternatives and resolve risks Initial operational capability (IOC) 5.Define next level of product and process, including partitions 6.(a) Validate product process definitions (b) Review and comment

28 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 Still Other Process Models  Component assembly model—the process to apply when reuse is a development objective  Concurrent process model—recognizes that different part of the project will be at different places in the process  Formal methods—the process to apply when a mathematical specification is to be developed  Cleanroom software engineering—emphasizes error detection before testing  Fourth generation technology (4GT)—enables specification of software at higher level, then generates codes automatically

29 These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001 References  Gavin (1984)  “What dos ‘product quality’ really mean?” Sloan Management Review, Fall:25-45.