Software configuration management (SCM) is responsible to establish and maintain the integrity of the products of the software project throughout the software life cycle. This includes identifying configuration items, controlling changes and recording and reporting the change implementation status. SCM is the task of tracking and controlling changes in the software. Configuration management practices include revision control and the establishment of baselines.
IEEE – A discipline applying technical and administrative direction and surveillance to: identify and document the functional and physical characteristics of a configuration item, and control changes to those characteristics, report change processing and implementation status, and verify compliance with specified requirements.
The software configuration management has four key components:
- Version Control
Version control is simply the automated act of tracking the changes of a particular file over time. This is typically accomplished by maintaining one copy of the file in a repository, then tracking the changes to that file (rather than maintaining multiple copies of the file itself).
- Build Management
Whether you choose to use automated tools to build your applications or still use a manual process, a software configuration management system helps you manage your process and results.
- Release Management
Release management is closely tied to build management. Release management includes the deployment process as well as the update of related metadata that goes into tracking a given version of a software application. The primary purpose of a release is to make the application available to its end users.
- Process Control
Process control is like an umbrella across the three key concepts already discussed. It is the combination of the business processes defined for your team and the implementation of these processes within your configuration management tool.
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UML Diagram:--
Activities Performed under SCM
Configuration identification - Identifying configurations, configuration items and baselines.
- Possible Configuration Items (CIs)
- System Specification
- Project Plan
- Requirements Spec
- Analysis Models
- Prototypes
- Use Cases
- Design Specs
- Data Design/Schema
- Architectural design
- Interface Design Spec
- Module Design Spec
- Catalogs & Classes
- Source Codes
- Libraries
- Test Specifications
- Test Plan and Procedures
- Test Cases
- Installation & User Manual
- Executables
- Standards
- Checklists
- Tools
- Baseline
- An aggregation of CIs that have been formally reviewed and agreed upon, and taken into control at a single point of time. One or more software configuration items that have been formally reviewed and agreed upon and serve as a basis for further development.
- Baseline acts as points of reversibility in the development life cycle.
- Possible Baseline Points
- Contract
- Functional Specifications
- Design
- Code & Unit Test
- Integration Test
- System Test
Configuration control - Implementing a controlled change process. This is usually achieved by setting up a change control board whose primary function is to approve or reject all change requests that are sent against any baseline.
- Change is logged.
- Evaluation of request - Impact, Risk, Priority.
- Change Control Board - Decision Authority.
- PM approves the change request.
- TM involvement for effort changes due to a CR.
- Draw implementation plan.
- “Check-out” CI’s - to dynamic folder of the user.
- Make the change, Review the change.
- “Check-in” CIs.
- Establish baseline.
Configuration status accounting - Recording and reporting all the necessary information on the status of the development process.
- Status of change requests, defect reports
- Version status of various Configuration items
- Status of Configuration items in various baselines.
Configuration status accounting needs to be done at the end of identified phase or milestones after ensuring that baseline record is updated to reflect the latest version numbers of the configuration items.
Configuration auditing - Ensuring that configurations contain all their intended parts and are sound with respect to their specifying documents, including requirements, architectural specifications and user manuals.
- Verifying that Configuration Management Process has been followed
- Adherence to Configuration Management Plan
- Contents of baselines - Intermediate and Release
- Change Management Process
- Control of changes to base lined items
- Defect logging and tracking
Build management - Managing the process and tools used for builds.
Process management - Ensuring adherence to the organization's development process.
Environment management - Managing the software and hardware that host our system.
Teamwork - Facilitate team interactions related to the process.
Defect tracking - Making sure every defect has traceability back to the source.
SCM Life Cycle model
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SCM plan divides the entire software life cycle into following phases to address and define the process and activities to be followed for reaching a milestone with history, traceability and reproducibility.
- Setting up workspace
- Development and defect fixing
- Code delivery and Daily Builds
- Initial Base lining
- IR Configuration Audit & Accounting
- Internal Release (IR)
- Testing and defect fixing
- Final Base lining
- Configuration Audit & Accounting
- External Release (ER)
Setting up workspace
Workspace is nothing but an independent work area of a developer to view, modify, build and test the source files without impacting another person’s work by providing enough isolation and privacy. The workspace is setup by developers with the assistance from SCM team.
- Creating a Workspace (Project/Private) folder for each task or user respectively depends on what kind of isolation is required for development work.
- Set up config_spec required for development work
- The check out and check in as follows
- Map your local workspace / folder directory path to SCM tool you are using.
- Selecting element versions from the starting baseline.
An element version will be pulled out into Workspace branch and will be checked out from there, when user issues a checkout
Development and Defect Fixing
This is the phase where developers do real coding work. This coding can be for accomplishing a task like feature or defect fix.
- Developers start their work in a Project using their local development.
- Once Project/ files are ready with development /enhancements or defect fixes, developers ensure to check in their changes with a brief comment on the comment section.
- Project/ files are merged into a respective folder on VSS with auto incremented.
Code Delivery & Daily Builds
Phase where completed work is delivered and integrated (merged) in a common area.
- Developer does a ‘merge out’ operation to merge LATEST versions of development folder from VSS to their local development. This is a mandatory step before developer delivers his/her changes.
- After ‘merge out’, developer must do a build and minimum level of testing to validate the integrity of the merge.
- After validating ‘merge out’ data, developer does a ‘merge in’ from local development to VSS.
Initial Base lining
SCM team baselines the integrated and build validated code and releases the software to test team along with build configuration
- Developer / lead hands over Release Main branch code to SCM team and provides config_spec to migrate ST and IT folder.
- SCM team creates a baseline complying with labeling standards.
- SCM and development lead will coordinate to migrate the code testing servers.
IR Configuration Audit & Accounting
Configuration Audit & Accounting is mandatory, because it gathers product statistics and preserves product history and traceability. It also validates the completeness of the product and consistency of its components by ensuring that they are in an appropriate state. Here it is done to validate the code to be given to test team for testing the product.
Internal Release
Internal release is the code release to test team basically for final testing and defect fixing of the product to qualify it for releasing to customer.
Testing and defect fixing
Phase where the product is tested vigorously, defects are found and fixed.
- Defect found during testing are logged into defect tracking system.
- Once defect fixing is done, lead will send a note to SCM team to migrate the code.
Final Baseline
In this phase test team hands over the tested and qualified code to SCM team, who creates a final baseline on this code. This baseline is used for the code release to customer.
- Test team informs test completion to SCM team and hands over list of defects found in testing phase.
- SCM team does following:
- Creates a Full External Release Baseline complying with labeling standards.
- Collects list of versions and verifies if they are modified for fixing defects. Reports the conflicts to test team and get them cleared.
- Verifies that testing defects are closed in defect tracking system.
- Creates final release baseline.
- Locks final release baseline, and code will be freeze, If changes made after code freeze require higher management approval to migrate the code.
Configuration Audit & Accounting
Configuration audit and analytics can help align the configuration of servers and other assets, contribute to proper capacity planning, validate the configuration of environments designed for business continuity, facilitate migrations from physical to virtual environments, and improve application lifecycles across an environment.
- In-process audits – verify the consistency of the design as it evolves through the development process
- Functional audits – verify that functionality and performance are consistent with requirements defined in the SRS
- Physical audits – verify that the as-built version of software and documentation are internally consistent and ready for delivery
- Quality system audits – independent assessment of the compliance to the software QA plan
Configuration status accounting is an activity of CM that is concerned with the recording and reporting of information required to effectively manage the configuration of a system or product. Configuration status accounting activities collect data that can be used to measure various aspects of program effectiveness and to assess product completeness and quality. The five (5) primary types of configuration status accounting reports identified for the AHRQ program are listed below and discussed in the following sections:
- CI Reporting.
- CR Reports.
- System Build Reports.
- Audit Reports.
- CM Metric Reports
External Release
External release is the release of final tested and qualified product to customer. This release goes through every step of formal release process
Benefits of SCM
1. Organizes tasks and activities that maintain the integrity of the software.
2. Helps manage assets.
3. Provides ability to track changes made during sequential or parallel development.
4. Ensures correct configurations of software.
5. Provides the ability to trace the process from requirement to product.
6. Limits legal liability by recording all data.
7. Helps reduce the life cycle cost of maintaining software which can exceed the initial cost of development.
SCM Summary
- Change is inevitable
- Defined procedures are required to manage change without preventing change
- Software presents many challenges from a control, management, and tracking perspective
- Knowing what you have and how you got there is very important
- Being able to recreate exactly what is delivered to customers is essential
Some Common SCM Tools
- SCCS, RCS (UNIX)
- Clear Case, Summit, CMVC (Rational)
- Visual SourceSafe (Microsoft)
- CVS, Bugzilla (open source and free software)
- Razor (Tower)
- Bugbase (Archimedes Software)
- Many other tools with CM capabilities (e.g. Requisite Pro and Rational Rose)
General information - SCM Tools
Software | Maintainer | Development status | Platforms supported | Cost | |||
AccuRev [5] | AccuRev, Inc. | actively developed | Merge or lock | $1495 (enterprise) for each license, free 5-user 30 day trial licenses available | |||
Bazaar[6] | actively developed | Merge | Free | ||||
BitMover Inc. | actively developed | Merge | Quoted on an individual basis. | ||||
actively developed | Merge or lock[2] | $4600 per floating license (held for 30-minutes minimum per user) | |||||
Reliable Software | actively developed | Merge | $150 per seat | ||||
Xerox | platform actively developed with CVS & Subversion | Merge or lock | Linux Red Hat Enterprise 5.x | Free- Commercial support subscription available | |||
Ross Cohen | actively developed | Merge | Free | ||||
The CVS Team [13] | maintained but new features not added | Merge | Free | ||||
March Hare Software[15] and community members. | maintained and new features under development | Merge or lock | GPL or proprietary | Free or commercial | |||
David Roundy | actively developed | Merge | Free | ||||
actively developed | Merge | Free | |||||
actively developed | Merge | Free | |||||
Andy Tai | maintained but new features not added | Merge | Free | ||||
IC Manage Inc. | actively developed | Merge or lock | Commercial | ||||
Artenum[22] | maintained and new features under development | Merge | Free | ||||
Matt Mackall | actively developed | Merge | Free | ||||
MKS Inc | actively developed | Merge or lock | |||||
Nathaniel Smith, Graydon Hoare | actively developed | Merge | Free | ||||
Perforce Software Inc. | actively developed | Merge or lock | Free for up to 2 users, and for OSS development; else $900 per seat, with volume discounts [27] | ||||
Codice Software[29] | actively developed | Merge | $500 per seat, with volume discounts, free 5-user 30 day trial licenses available [30] | ||||
actively developed | Merge or lock | Windows and Cross-platform via Java based client | $7500 per concurrent, $2500 per fixed user. | ||||
CollabNet, Inc.[33] | actively developed | Merge or lock[5] | Free (Commercial support/services available) | ||||
Best Practical[35] | maintenance through 2010, no new features[6] | Merge | Free | ||||
actively developed | Merge or lock | Proprietary | Server: Windows Server 2003; Clients: Windows and Web included | Licensed through MSDN subscription or through direct buy for $2800 [37] | |||
actively developed | Merge or lock | Proprietary | Contact Telelogic [39] | ||||
SourceGear LLC[41] | actively developed | Merge or lock | Proprietary | $300 per user | |||
serious bug fixes only | Merge or lock | Proprietary | ~$500 per license or single license included with each MSDN subscription. | ||||
Software | Maintainer | Development status | Platforms supported | Cost |
Source Control Server and Client
Source Control Server –It is software that really does the software tracking and storage of files. You must install the server software in a secure computer in your office. This will be the machine where the files and multiple versions of them are stored. So it is important that this machine is protected from direct access of any of the members in your team
Source control Client - Users perform all actions through the client software. The client software will communicate with the server software to execute the user tasks. All files will be stored and retrieved to this machine using the Source Control client software. Each member of the team should install the client software in their machines. The client software will send and receive files with the server software. So, the team members do not need direct access to the server computer.
INTRODUCTION
Microsoft Visual source safe – Source Control System
Microsoft Visual SourceSafe also called ‘VSS’ is a file-system-based source control tool from Microsoft. Microsoft Visual SourceSafe is a file-level version control system that permits many types of organizations to work on several project versions at the same time. This capability is particularly beneficial in a software development environment, where it is used in maintaining parallel code versions. However, the product can also be used to maintain files for any other type of team...
At a minimum, Visual SourceSafe does the following:
- Helps protect your team from accidental file loss.
- Allows back-tracking to earlier versions of a file.
- Supports branching, sharing, merging, and management of file releases.
- Tracks versions of entire projects.
- Tracks modular code (one file that is reused, or shared, by multiple projects).
Powerful Operations
Add Files, Create Project, Delete Files or Projects, Get Latest Version, Check Out, Check In, Undo Check Out, Move, Deploy, Share, Branch, View, Edit, Show Difference, Set Working Folder, Refresh File List, Refresh Project Tree, Stop Current Operation, Show Properties, Show History, Label, Pin, Rename, Change Password, Cloak Project.
Summary
Source control system helps
1. Keep backup of your source code or documents.
2. Maintain all versions of your files so that you can retrieve any of the old versions of the file easily without searching all over your hard drive.
3. Track which person changed what and when.
4. Control who changes the file to avoid more than one person changing the file at the same time.
5. At any point of time, any of the team members can get the latest version of all files from one single location, without the need to ask each member for the latest files.
6. Track progress - project manager or team leader can monitor the file change activity in source control systems to find out how much work each person has done on each day.
1 comments:
An advantage of a configuration management application is that the entire collection of systems can be reviewed to make sure any changes made to one system do not adversely affect any of the other systems.
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