2. Contents Characteristics of Todays Software industry SCM Concepts and terminology Why Software configuration management? Requirements of Configuration management Standard reports Typical Uses of SCM
3. The Fundamental Law of Configuration Management
Configuration Management is the foundation of a software project. Without it, no matter how talented the staff, how large the budget, how robust the development and test processes, or how technically superior the development tools, project discipline will collapse and success will be left to chance. Do Configuration Management right, or forget about improving your development process.
4. Why did the Tower of Babel fail? The Tower of Babel project failed because of lack of communication and organization
5. Today's Software industry characteristics are..
6. Characteristic 1 - Coordination & Communication Men and months cannot be interchanged Fred Brooks
Number of communication channels increase exponentially with number of team members - the number of coordination problems also increase exponentially with the project size.
7. Communication Channels
8. # Team Members #Communication Channels 1 0 2 1 3 3 4 6 5 10 .. .. n n*(n-1)/2
9. Characteristic 2 - Software is Easy to Copy
10. Characteristic 3 - Changes
Different users / customers have different requirements
Get clarified / known at a later date
Changes to business environment
11. Characteristic 4 - Personnel Turnover
Further Adds to the Coordination problem
12. Resulting Problems
Listing seems OK; program does not work
Works in Bombay, misbehaves in Delhi
We had customized for this client, how do we install the upgrade now?
I had fixed this bug last month. How did it re-appear?
I havent changed the program. Why is it now blowing up?
Which is the latest source? I need to put a patch.
In the last month, the user asked for this change and now she does not want it
Where did Gates leave the programs he was working on?
13. Main Classes of Problems
Double maintenance problems
Missing / unknown version problem
14. Double Maintenance
Multiple copies of same software in use
Fix in one
- SHOULD FIX IN OTHERS
- Same set of common routines in two systems
- Same system - multiple sites
forget to inform
sites detect bug at same time and fix differently
= = > > DIVERGENCE
- Bug fixed in all copies
- Fix same bug in identical manner in all copies
15. Shared Data
Changes made in one program interfere with proper functioning of other program
- Example : subroutines, MW objects
- Control of modifications
- Good communications
16. Simultaneous Update
One module being worked on by more than one programmer
- Changes made by one programmer disappear
- Better division into modules
- Ensure simultaneous working
17. Missing / unknown Version problem
Consciously decide which version to keep, which to destroy
Use a systematic method to identify versions and changes across versions
Use consistent back-up procedures
18. Why Software Configuration Management
SCM addresses all these issues!!
SCM provides visibility into the status of the evolving software product.
SCM answers the following: Who, What, When, and Why.
Who made the changes?
What changes were made to the software?
When were the changes made?
Why were the changes made?
Who will benefit from SCM(Importance in descending order) :
Quality Assurance (QA) personnel
20. Program Families & Configurations A D E B C F A CLIENT-1 D G B W E F CLIENT-2 Applications Applications
21. A D E B C F G W CLIENT-A A B C D E F CLIENT-B A B D E F G W Applications
22. SCM Concepts & Terminology
23. Definitions The arrangement of a computer system or component as defined by the number, nature, and interconnections of its constituent parts Configuration The art of identifying, organizing and controlling modifications to the software being built by a programming team. The goal is to maximize productivity by minimizing mistakes. Configuration Management
24. Configuration Management
25. Configuration Identification
The approved documentation or description that identifies and defines a configuration item's (CI) functional and physical characteristics in the form of a specification or standard, algorithm or code, and interface control description .
A B C D
26. Configuration Control
Evaluation, coordination, approval or disapproval, and implementation of changes to configuration items after formal establishment of their configuration identification
27. Configuration Status Accounting
Recording and reporting of information needed to manage a configuration effectively. Includes a listing of the approved configuration identification, the status of the proposed changes to the configuration identification, and the implementation status of approved changes.
CI = 30 CR = 2 PR = 1
28. Configuration Audit
Verifying the following:
All required configuration items have been produced
The current version agrees with the specified requirements
The technical documentation completely and accurately describes that configuration items
All change requests have been resolved
29. Requirements of Configuration Management
30. CM Requirements
Identification of Configuration Items
Establishment of Baselines
Management of Workspaces
Creation of Builds
Backup & Archival
Management of Changes to Baselined Configuration Items