Introduction and Overview

Transcription

1 Introduction and Overview Lecture 1 Software Engineering CUGS course Spring 2011 Kristian Sandahl Department of Computer and Information Science Linköping University, Who is Kristian? 2 Gotland Småland Linköping Naval HQ Protein purification Ericsson I 1

2 Agenda 3 Definition and role of software engineering I I 4 Definition and role of Software Engineering I 2

3 5 How the customer explained it I 6 How the project leader understood it I 3

4 7 How the analyst designed it I 8 How the programmer wrote it I 4

5 9 How the business consultant described it I 10 How the project was documented I 5

6 11 What operations installed I 12 How the customer was billed I 6

7 13 How it was supported I 14 Finally, what the customer really needed I 7

8 Why do we need SE? 15 Frequent failures: Space shuttle Nike Denver airport LA airport Charette, R.N. (2005) Why Software Fails, IEEE Spectrum, September 2005 Geppert, L (2004) Lost Radio Contact Leaves Pilots On Their Own, IEEE Spectrum, Nov 2004 I Software Engineering 16 Application of systematic, disciplined, quantifiable approach to software development, operation and maintenance of software. (IEEE-Std.) I 8

9 Studying SE theory 17 Reading about concepts and methods derived from experience Almost everything have their pros and cons Quite little is based on mathematical theory Requires disciplined plan for reading different sources I Studying SE theory 18 Your job Find central concepts and methods over the entire field Study their applicability, pros and cons Practice analysing and designing small examples Participate in examination Ask us questions Give us suggestions for further improvement Our job Account for the most central concepts in lectures Set things in context Discuss industrial relevance Arrange examination Answer your questions Listen to B:470 Subject: DF14900 I 9

10 Ambition level 19 You will know enough to communicate easily with professional software engineers You will have the basic knowledge to start generating your own experience, perhaps already obtained You will have a curious, but critical, attitude towards existing and new methods I 20 I Contents of a Software Life Cycle I 10

11 Abstraction Scope of a software life-cycle model 21 Idea Software Product Usage Operation & maintenance Replacement I Model of a life-cycle 22 Carol the customer Diana the developer Time I 11

12 23 Elicitation Analyze Specify Validate Collect user requirement Understand Document Check that it matches user requirements I 24 Functional requirements A required behavior or function E.g. "delete material items" Non-Functional requirements Quality requirements E.g. performance, scalability, usability maintainability, etc. I 12

13 and 25 Validate, Verify Specification I 26 Validate, Verify Specification Decompose into sub-systems or modules Well-defined interfaces High level of abstraction Module 1 Module 2 Module 3 Architecture styles, e.g. Client-server Layered Models Pipes and Filters I 13

14 System and Module Design 27 Validate, Verify Specification Module Design (Program Design, Detailed Design) Unified Modeling Language (UML) Use a standardized way to model system graphically Design Patterns Reuse design solution that has worked before I Testing 28 Validate, Verify Specification System Testing (Integration testing of modules) Module Design (Program Design, Detailed Design) Verify Module Design Verify Module Testing (Integration testing of units) of Units (classes, procedures, functions) Unit testing I 14

15 Testing Validate, Verify Specification 29 System Testing Integration testing Dependencies between modules (Integration testing of modules) Approaches Verify Module Design Module Design Top-down (need stubs) Module Testing (Program Module Design, 1 Module 2 Bottom-up (need drivers) Detailed Design) Verify Sandwich Big-bag (Integration testing of units) Module 3 of Units (classes, procedures, functions) Unit testing I Supporting Processes 30 Validate, Verify Specification Verify System Testing (Integration testing of modules) Module Design (Program Design, Detailed Design) Verify Module Design Verify Module Testing (Integration testing of units) of Units (classes, procedures, functions) Unit testing I 15

16 Inspection Validate, Verify Specification Inspection Formal Inspection Reviewing with a defined process Aim at finding Verify defects Works in practice 31 System Testing (Integration testing of modules) Module Design (Program Design, Detailed Design) Verify Module Design Verify Module Testing (Integration testing of units) of Units (classes, procedures, functions) Unit testing I Software Life Cycles, Configuration Mgm. Software Life Cycles and Configuration Validate Management, Verify Specification V-model Waterfall model Verify 32 System Testing (Integration testing of modules) Module Design (Program Design, Iterative models Detailed Design) Verify Configuration Management (CM) Unit testing of Units (classes, procedures, functions) Verify Module Design Keep track of versions. Used the wrong code-base. R Module R R Testing (Integration testing of units) I 16

17 Software Quality Management 33 Validate, Verify Specification Verify Software Quality Management Different qualities Verify Module Design Module Design Quality of product (Program Design, Quality of process Detailed Design) Quality in Verify a business environment System Testing (Integration testing of modules) Module Testing (Integration testing of units) of Units (classes, procedures, functions) Unit testing I Software Life Cycles, Configuration Mgm. Project Management Resources Milestones Time-budget Validate, Verify Specification Calendar-time Time plan Verify Resource management Time-buffer Verify Module Design Module Internal Design milestones - keep track (Program Design, Detailed Design) Activities Verify 34 System Testing (Integration testing of modules) Module Testing (Integration testing of units) Risk Management of Units (classes, procedures, functions) Identify Analyze Plan Unit testing - Minimize - Transfer - Accept probability - consequence I 17

18 A Software Life-cycle 35 Maintenance Validate, Verify Specification Module Design (Program Design, Detailed Design) Verify Verify Module Design Verify System Testing (Integration testing of modules) Module Testing (Integration testing of units) of Units (classes, procedures, functions) Unit testing Project Management, Software Quality Assurance (SQA), Supporting Tools, Education I Summary 36 Maintenance Validate, Verify Specification Module Design (Program Design, Detailed Design) Verify Verify Module Design Verify System Testing (Integration testing of modules) Module Testing (Integration testing of units) of Units (classes, procedures, functions) Unit testing Project Management, Software Quality Assurance (SQA), Supporting Tools, Education I 18