Software Configuration Management(SCM)

By,Muhammad Imran HashimSQA EngineerVisualSoft (Pvt) Ltd.imran@visualsoft-inc.comimranh9@hotmail.com

ObjectivesObjectives

• To explain the importance of software configuration management (SCM)

• To describe the key SCM activities namely SCM planning, change management, version management and system building

• To describe the functions of SCM tool Microsoft Visual Source Safe 6.0

Topics coveredTopics covered

• SCM Definitions • SCM Process overview• SCM Plan• SCM Functions• System Building• Basic SCM Concepts• SCM Tool (Microsoft Visual Source Safe 6.0)• VSS concepts

DefinitionsDefinitions

• SCM systems typically offer version control and team programming features.

• Software Configuration management is a method of bringing control to the software development process.

Configuration managementConfiguration management

• New versions of software systems are created as they change:– For different machines/OS;– Offering different functionality;– Tailored for particular user requirements.

• Configuration management is concerned with managing evolving software systems:– System change is a team activity;

– CM aims to control the costs and effort involved in making changes to a system.

Configuration managementConfiguration management

• Involves the development and application of procedures and standards to manage an evolving software product.

• CM may be seen as part of a more general quality management process.

• When released to CM, software systems are sometimes called baselines as they are a starting point for further development.

SCM Process OverviewSCM Process Overview

The process is divided in three parts:

• Firstly SCM function should identify the configuration items and document their characteristics.• Once configuration items are identified and their characteristics are documented then SCM system should control the changes to those characteristics.• Third, the SCM system should record the change management process.

SCM PlanSCM Plan

The best place to record how SCM should be performed for each project is in the SCM plan.

The SCM plan document following :

• What SCM activities are to be done.• How they are to be done.• Who is responsible for doing specific

activities.• When they are to happen.• What recourses are required.

SCM PlanningSCM Planning

• Defines the types of documents to be managed and a document naming scheme.

• Defines who takes responsibility for the CM procedures and creation of baselines.

• Defines policies for change control and version management.

• Defines the CM records which must be maintained.

SCM PlanningSCM Planning

• Describes the tools which should be used to assist the CM process and any limitations on their use.

• Defines the process of tool use.• Defines the CM database used to record

configuration information.• May include information such as the CM of external

software, process auditing, etc.

SCM planningSCM planning

• All products of the software process may have to be managed:– Specifications;– Designs;– Programs;– Test data;– User manuals.

• Thousands of separate documents may be generated for a large, complex software system.

SCM FunctionsSCM Functions

• Configuration Identification• Configuration Control• Status Accounting (Recording & Reporting)• Audits & Reviews

SCMSCM standardsstandards

• CM should always be based on a set of standards which are applied within an organisation.

• Standards should define how items are identified, how changes are controlled and how new versions are managed.

• Standards may be based on external CM standards (e.g. IEEE standard for CM).

• Some existing standards are based on a waterfall process model - new CM standards are needed for evolutionary development.

• Software systems are subject to continual change requests:– From users;– From developers;– From market forces.

• Change management is concerned with keeping track of these changes and ensuring that they are implemented in the most cost-effective way.

Change managementChange management

Version management toolsVersion management tools

• Version and release identification– Systems assign identifiers automatically when a

new version is submitted to the system.• Storage management.

– System stores the differences between versions rather than all the version code.

• Change history recording– Record reasons for version creation.

• Independent development – Only one version at a time may be checked out for

change. Parallel working on different versions.

Delta-based versioningDelta-based versioning

Version1.0

Version1.1

Version1.2

Version1.3

D1 D2 D3

Creation date

System buildingSystem building

• Building a large system is computationally expensive and may take several hours.

• Hundreds of files may be involved.• System building tools may provide

• A dependency specification language and interpreter;

• Tool selection and instantiation support;• Distributed compilation;• Derived object management.

Component dependenciesComponent dependencies

comp

scan.o syn.o sem.o cgen.o

scan.o syn.o

defs.h

sem.o cgen.o

BaselinesBaselines

Baseline is an SCM concept that helps to control change. When configuration item is complete it is handed over to the configuration management team for safekeeping. The configuration management team will check whether the item that is given to them is complete per the SCM plan and assigns to a baseline to it. So once a baseline is established for a configuration item, then that item can be changed only through a formal change management process.

Check-in/ Check-outCheck-in/ Check-out

• The process of copying the item from the controlled

library is called Check-out process.• The process of reviewing, approving and moving an

item into the controlled environment is called check- in.

Change request analysis, approval,etc.

Software Configuration Managemet

Configuration ItemRevised

Configuration Item

Test, Review,Approve

Check-out Check-in

Modifications

SCM Tool

Microsoft Visual Source Safe 6.0

Visual Source Safe 6.0Visual Source Safe 6.0

Microsoft VSS helps to manage your projects,

regardless of the file type (text files, graphics files, binary files, sound files, or video files) by saving them to a database.

VSS project organization makes team coordination easy.

Visual Source Safe 6.0Visual Source Safe 6.0

• Visual SourceSafe 6.0 is a member of the Visual Studio 6.0 family of development products which includes:

• Visual Basic• Visual C++• Visual FoxPro• Visual InterDev• Visual J++• .Net

Visual Source Safe 6.0Visual Source Safe 6.0

• Keeps all sources together in one place.• Keeps history of all files.• Controls access to resources.• Physically safe resources – files and its history are stored in the VSS incremental database which is easy to backup. • Security by managing access rights to projects for all users.• Versioning.

VSS Administrative TasksVSS Administrative Tasks

• Create new database

• Add/Delete users• Change passwords• Allow multiple checkouts• Lock database• Rights by projects

VSS Client TasksVSS Client Tasks

• Create Projects (Folders)• Add Files• View / Edit• Set Working Folder• Check Out• Check In• Show History• Get Latest Version• Label Version• View Differences

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