Lecture Software process improvement: Lesson 3 provide students with knowledge about: configuration management; change; software configuration management; SCM functions; purpose of SCM activities; SCM provides cover against;... Please refer to the detailed content of the lecture!
Configuration Management Lecture # 3 Agenda • Change • Software configuration management • SCM Functions Change • Changes will happen in all work products and during all processes during software development and maintenance • Change increases the level of confusion among software engineers who are working on a software project Sources of Change 1 • New business or market conditions dictate changes in product requirements or business rules • New customer needs demand modification of data produced by information systems, functionality delivered by products, or services delivered by computerbased system Sources of Change 2 • Reorganization or business growth / downsizing causes changes in project priorities or software engineering team structure • Budgetary or scheduling constraints cause a redefinition of the system or product Why All This Modification? • As time passes, all constituencies know more – About what they need – Which approach would be best – How to get it done and still make money • Most changes are justified! Confusion • Confusion arises when changes are not – – – – Analyzed before they are made Recorded before they are implemented Reported to those who need to know Controlled in a manner that will improve quality and reduce errors • We need to minimize this confusion, or else our projects will get out of control Configuration Management • The art of coordinating software development to minimize confusion is called configuration management • The goal is to maximize productivity by minimizing mistakes Software Configuration Mgmt • SCM is a set of activities designed to control change by identifying the work products that are likely to change – establish relationships among them – defining mechanisms for managing different versions of these work products – controlling the changes imposed – auditing and reporting on the changes Purpose of SCM Activities • Identify change • Control change • Ensure that the change is being properly implemented • Report changes to others who may be interested 10 The Change Control Process 1 need for change is recognized change request from user developer evaluates change report is generated change control authority decides request is queued for action change request is denied user is informed Change Control Process—2 36 The Change Control Process 2 assign people to SCIs checkout SCIs make the change review/audit the change establish a “baseline” for testing Change Control Process—3 37 The Change Control Process 3 perform SQA and testing activities checkin the changed SCIs promote SCI for inclusion in next release rebuild appropriate version review/audit the change include all changes in release 38 Change Control Process • As you can notice, that formal change control process is very elaborate and comprehensive process • The “checkin” and “checkout” activities implement two important elements of change control – access control and synchronization control 39 Access and Synchronization Control • Access control governs which software engineers have the authority to access and modify a particular configuration item • Synchronization control helps to ensure that parallel changes, performed by two different people, don’t overwrite one another • We need to implement both 40 SCM Function: Configuration Audit 1 • A software configuration audit complements the formal technical reviews/inspections by assessing a configuration item for characteristics that are generally not considered during review • The SCM audit is conducted by the quality assurance group 41 SCM Function: Configuration Audit 2 • Has the change specified in the ECO been made? Have any additional modifications been incorporated? • Has a formal technical review been conducted to assess technical correctness? • Has the software process been followed and have software engineering standards been properly applied? 42 SCM Function: Configuration Audit 3 • Has the change been “highlighted” in the SCI? Have the change date and author been specified? Do the attributes of the configuration object reflect the change? • Have SCM procedures for noting the change, recording it, and reporting it been followed? • Have all related SCIs been properly 43 updated? SCM Function: Status Accounting/Reporting • The status accounting function provides a corporate memory of project events that supports accomplishment of other configuration management items – – – – What happened? Who did it? When did it happen? What else will be affected? 44 Software Configuration Management Overview 45 Software Configuration Management Overview Initial Development Requirements/ Design/Use Approve Change Establish/ Update Baseline Validate Baseline Authorize Change Implement Change Validate Change Baselines Changes 46 Management Commitment to SCM 47 Management Commitment for SCM Product Development SCM Software Project Management Commitment 48 Summary • Software configuration management is an umbrella activity that is applied throughout the software process • SCM identifies, controls, audits, and reports modifications that invariably occur while software is being developed and after it has been released • SCM saves a project from total chaos 49 References • Software Engineering: A Practitioner’s Approach by Roger S. Pressman (Chapter 9.1 – 9.9) • A Handbook of Software Quality Assurance edited by G. Gordon Schulmeyer and James L. McManus, PH, 1999, (Chapter 10.110.2) • Managing the Software Process by Watts S. Humphrey, AW, 1989, page 177 (figure 7.2 SCM Overview) 50 ... Change Control? ?Process? ??2 36 The Change Control? ?Process? ? 2 assign people to SCIs checkout SCIs make the change review/audit the change establish a “baseline” for testing Change Control? ?Process? ? ?3 37 The Change Control? ?Process? ?? ?3. .. Documents that describe the computer programs – Data • Software? ?configuration items will grow 12 Baseline every? ?Software? ? Configuration Item 13 How to Manage Change? • A baseline is a? ?software? ?configuration management concept that helps us to ... In the context of? ?software? ?engineering, a baseline is a milestone in the development of? ?software? ?that is marked by the delivery of one or more? ?software? ?configuration items and approval of these? ?software? ?