15.1.2003 Software Engineering 2003Jyrki Nummenmaa

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CONFIGURATION MANAGEMENT

• Today we talk about Software Configuration Management (SCM for short):- What?- Why?- How?

15.1.2003 Software Engineering 2003Jyrki Nummenmaa

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WHY CM?

• Multiple people are working on changing software• More than one version of the software needs to be

supported:– Different releases– Different installations with different functionalities– Development versions

• Software needs to run on different operating systems and different hardware

15.1.2003 Software Engineering 2003Jyrki Nummenmaa

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WHAT IS SCM?

• Configuration management is a way to manage evolving software

• Configuration management is a set of disciplines and techniques for initiating, evaluating, and controlling change to software products.

• Configuration management covers the lifecycle of software development

15.1.2003 Software Engineering 2003Jyrki Nummenmaa

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SCM Activities

• CM data management• Version management

- Release versions- Development versions

• Concurrent development management• Change management

15.1.2003 Software Engineering 2003Jyrki Nummenmaa

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SCM Items

• Design documents• Code files• Test data• Test drivers• Manuals• System configuration data• Etc.• A meaningful combination of above, meant to be

treated as a single entity

• Also hardware items can be considered CM Items

15.1.2003 Software Engineering 2003Jyrki Nummenmaa

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Managing SCM Items

• There may easily be thousands of SCM items• A naming scheme should be introduced to identify

these• The hierarchical arrangement of software project

items should be supported• Should all CM items be managed• When to start management for an item?

– If you start too early, you get bureaucracy.– If you start too late, you get chaos.

15.1.2003 Software Engineering 2003Jyrki Nummenmaa

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Baselines

• Baseline: A specification or a product, which is formally reviewed and agreed on, and which can only be changed through formal change procedures

• Before an item becomes a baseline, changes can be made quickly and informally.

• Baseline is a kind of a milestone in software development

• Baseline typically creates new versions in SCIs.

15.1.2003 Software Engineering 2003Jyrki Nummenmaa

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Version control

• Procedures and tools to manage different versions of configuration objects

• Versions may not always be created in sequential order, e.g. you create 1.0 -> 1.1 -> 1.2 -> 2.0 and then you need to create 1.3 for some customers who can not run 2.0 but need some changes or improvements.

• With big software, you may e.g have 4.0 as the official current version. You work on 5.0 to release it as the next official version, but you have already started to create 6.0, as it takes so long to get it ready.

15.1.2003 Software Engineering 2003Jyrki Nummenmaa

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Change Control / 1

1. Need for change is recognised2. Someone (like a user) makes a change request3. Developer evaluates4. Change report is generated5. Change control authority decides

- Change is denied -> User is informed- Change is accepted -> go to next slide :)

15.1.2003 Software Engineering 2003Jyrki Nummenmaa

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Change Control / 2

6. Change request is queued for action and and engineering change order (technical descr) is made

7. Assign individuals to make changes to configuration objects

8. ”Check out” configuration items from project repository

9. Make the change10. Review (audit) the change11. ”Check in” the changed configuration items12. Establish a baseline for testing the changego to next slide :)

15.1.2003 Software Engineering 2003Jyrki Nummenmaa

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Change Control / 3

13. Perform quality assurance (QA) and testing activities

14. ”Promote” changes for inclusionin next release15. Rebuild appropriate version of software16. Review (audit) the change to all configuration

items17. Include changes in new version18. Distribute the new version

15.1.2003 Software Engineering 2003Jyrki Nummenmaa

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SCM Audit / 1

The following questions should be answered1. Has the change specified in the ECO been made?

Have any additional modifications been incorporated?

2. Has formal technical review been conducted to assess technical correctness?

3. Has the software process been followed and SE standards been applied?

4. Has the change been appropriately recorded in the SCIs?

15.1.2003 Software Engineering 2003Jyrki Nummenmaa

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SCM Audit / 2

More questions to be answered:5. Have Software Configuration Management

procedures for the change been followed?6. Have all related SCIs been properly updated?