Software Configuration Control Tools Summary

1
Software Configuration Control Tools Summary

• Peter Kim
• June 2004

2
Software Configuration Management

• Configuration management (CM) is a discipline
  whose goal is to control changes to large
  software through the functions of component
  identification, change tracking, version
  selection and baselining, software manufacture,
  and managing simultaneous updates (team work).
  Tichy 1988

3
The Need for Configuration Management

• Some of the problems that CM addresses
• Simultaneous update
• Shared code
• Common code
• Version control

4
SCM Potential Problems

• There are many potential problems that may appear
  with the SCM
• Managing many items large number of documents,
  code, variants.
• Simultaneous updatewhen two or more developers
  are working on the same code at the same time.
• Shared codewhen a fix is made to code that
  others rely on, they need to be notified.
• Common codewhen fixes are made to reuse
  libraries, or common code.

5
CM System functions

• SCM systems addresses these questions
• What is the current configuration
• What is the status
• How do I control changes to the configuration
• How do I inform others of my changes
• What are the changes that have been made to the
  system
• Do these changes affect my code?

6
SCM

• All SCM systems should ensure proper backup and
  recovery processes
• Configuration Control
• Change Management
• Revisions
• Versions
• Deltas/ Change Packages/ Change Sets
• Conditional Code

7
SCM Member Roles

• Configuration Manager Responsible for
  identifying configuration items. The
  configuration manager can also be responsible for
  defining the procedures for creating promotions
  and releases
• Change control board member Responsible for
  approving or rejecting change requests
• Developer Creates promotions triggered by change
  requests or the normal activities of development.
  The developer checks in changes and resolves
  conflicts
• Auditor Responsible for the selection and
  evaluation of promotions for release and for
  ensuring the consistency and completeness of this
  release

8
SCM Terms
1.0

• Baseline an authorized software work product
  that can only be changed through formal change
  control procedures
• Version An identified and documented software
  product

1.1
1.2
2.0
2.1
9
SCM
1.0

• Branching A variant development path that
  diverges from the primary development path
• Variants An alternative form of a configuration
  item

1.1
1.2
1.2.1.0
2.0
1.2.1.1
2.1
10
SCM
1.0

• Merging the activity of joining modifications
  performed simultaneously to different copies of
  the same module

1.1
1.2
1.2.1.0
2.0
1.2.1.1
2.1
MERGE
11
SCM Process
12
CVS

• Concurrent Version System
• Open source project-- still widely used
• Can record the history of your source files
• For each change who, when, and comments
• Non-exclusive control access to one file by
  multiple developers

13
CVS functions

• Stores entire history of each file efficiently
• Allows multiple developers to work simultaneously
• Enables retrieval of old systems
• Helps manage different versions, releases
• Works for any ASCII file limited support for
  binaries

14
CVS

• CVS is not the following and was not designed to
  be these functions
• A build system
• A substitute for management or communication

15
CVS

• Server should be Unix/Linux
• Local machine can be any OS
• Repository Central
• Local copy Editing
• Add, remove, commit, tag, checkout, update, diff

16
CVS

• Update frequently stay in sync with repository
• Commit changes frequently
• Should not share code except through the
  repository
• Build early and often
• Most CVS repositories now have GUI front-ends

17
CVS Screenshot (Eclipse)
18
Rational ClearCase

• Powerful tool for revision control of source code
  and development
• Versioned file system, which can be mounted as a
  virtual file system allowing for the production
  of derived objects
• Uses Versioned Object Bases to allow for
  distributed peer-to-peer repositories (with
  add-on modules)

19
ClearCase Menu Options (as seen from WSAD)
20
ClearCase Screenshots

• ClearCase graphical version tree GUI. The
  version tree shows the versions of a repository
  element and merge arrows, labels and branch names
• The annotations describe the different elements
  of the interface and some of the toolbar controls
  all of which are accessible from the keyboard,
  context menu, and toolbar menu.

21
ClearCase Graphical Tree

• The first screenshot is a simple view of a
  relatively new file. It was created on the
  dev_ng branch, then merged onto dev_lj and
  dev_anno_lj.
• The 0 versions are only placeholders on empty
  branches

22
ClearCase Graphical View of Code Branches
http//www.mit.edu/afs/sipb/project/subversion/src
/svn/notes/guis/pics/ClearCase-lsvtree-1.gif
23
ClearCase Screen 2

• Same file, but showing only versions contributing
  to the version in the current view
• The tooltip that shows up can also show the
  versions change log
• The change log can be configured to show up at
  check-out which may be useful as a reminder to
  the developer (and others) to see what is being
  done to the file

24
ClearCase2
http//www.mit.edu/afs/sipb/project/subversion/src
/svn/notes/guis/pics/ClearCase-lsvtree-2.gif
25
ClearCase Screen 3

• Same as the first screen, but with Show all
  Versions turned off
• Only contributors, merge sources, or merge
  targets are shown

26
ClearCase3
http//www.mit.edu/afs/sipb/project/subversion/src
/svn/notes/guis/pics/ClearCase-lsvtree-3.gif
27
ClearCase Screen 4

• Real-Life example
• At first confusing, but eventually users can get
  used to it.

28
ClearCase4
http//www.mit.edu/afs/sipb/project/subversion/src
/svn/notes/guis/pics/ClearCase-lsvtree-4.gif
29
SCM

• Implementing SCM in your organization requires
  support from all areas especially management
• On larger systems, a CCB is mandatory
• Automated tools are essential for proper CM
  activity

30
Conclusions

• CM is changing
• Broader scope, wide-ranging responsibility,
  intermingling with other disciplines
• CM tools will change as well
• Design, development, deployment, and run-time,
  not just implementation