Scm
- 1. © 2003 IBM Corporation Why did the Tower of Babel fail? Siva Prasanth Rentala GM-WWP, Pune
- 2. Configuration Management © 2003 IBM Corporation Why did the Tower of Babel fail? The Tower of Babel project failed because of lack of communication and organization.
- 3. Configuration Management © 2003 IBM Corporation "Now the whole earth had one language and few words. And as men migrated from the east, they found a plain in the land of Shinar and settled there. And they said to one another, 'Come, let us make bricks, and burn them thoroughly.' And they had brick for stone, and bitumen for mortar. Then they said, 'Come, let us build ourselves a city, and a tower with its top in the heavens, and let us make a name for ourselves, lest we be scattered abroad upon the face of the whole earth.' And the LORD came down to see the city and the tower, which the sons of men had built. And the LORD said, 'Behold, they are one people, and they have all one language; and this is only the beginning of what they will do; and nothing that they propose to do will now be impossible for them. Come, let us go down, and there confuse their language, that they may not understand one another's speech.' So the LORD scattered them abroad from there over the face of all the earth, and they left off building the city.' Therefore its name was called Babel, because there the LORD confused the language of all the earth; and from there the LORD scattered them abroad over the face of all the earth."
- 4. Configuration Management © 2003 IBM Corporation Contents Characteristics of Today’s Software industry SCM Concepts and terminology Why Software configuration management? Requirements of Configuration management Standard reports Typical Uses of SCM
- 5. Configuration Management © 2003 IBM Corporation 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.
- 6. © 2003 IBM Corporation Today's Software industry characteristics are..
- 7. © 2003 IBM Corporation 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.
- 8. Configuration Management © 2003 IBM Corporation Communication Channels
- 9. Configuration Management © 2003 IBM Corporation # Team Members #Communication Channels 1 0 2 1 3 3 4 6 5 10 ….. ….. n n*(n-1)/2
- 10. Configuration Management © 2003 IBM Corporation Characteristic 2 - Software is Easy to Copy
- 11. Configuration Management © 2003 IBM Corporation Characteristic 3 - Changes • Different users / customers have different requirements • Get clarified / known at a later date • Changes to business environment • Technology change • Personnel whims
- 12. Configuration Management © 2003 IBM Corporation Characteristic 4 - Personnel Turnover • Developers leave • Users change Further Adds to the Coordination problem
- 13. Configuration Management © 2003 IBM Corporation Resulting Problems • Listing seems OK; program does not work • Works in Pune, misbehaves in Detroit. • 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 haven’t 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?
- 14. Configuration Management © 2003 IBM Corporation Main Classes of Problems • Double maintenance problems • Shared data • Simultaneous update • Missing / unknown version problem
- 15. Configuration Management © 2003 IBM Corporation Double Maintenance • Multiple copies of same software in use • Fix in one - SHOULD FIX IN OTHERS • Example - 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 • Should do - Bug fixed in all copies - Fix same bug in identical manner in all copies
- 16. Configuration Management © 2003 IBM Corporation Shared Data • Changes made in one program interfere with proper functioning of other program - Example : subroutines, MW objects • Need - Control of modifications - Good communications
- 17. Configuration Management © 2003 IBM Corporation Simultaneous Update • One module being worked on by more than one programmer - Changes made by one programmer disappear • Need - Better division into modules - Ensure simultaneous working
- 18. Configuration Management © 2003 IBM Corporation 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 ?
- 19. Configuration Management © 2003 IBM Corporation Why Software Configuration Management • SCM addresses all these issues!! AbracadabraAbracadabra
- 20. Configuration Management © 2003 IBM Corporation 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) : Software developers Project managers Quality Assurance (QA) personnel Testers Customer
- 21. Configuration Management © 2003 IBM Corporation Program Families & Configurations A D E B C F A CLIENT-1 D G B W E F CLIENT-2 Applications Applications
- 22. Configuration Management © 2003 IBM Corporation 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
- 23. Configuration Management © 2003 IBM Corporation SCM Concepts & Terminology
- 24. Configuration Management © 2003 IBM Corporation 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
- 25. Configuration Management © 2003 IBM Corporation Configuration Management
- 26. Configuration Management © 2003 IBM Corporation 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
- 27. Configuration Management © 2003 IBM Corporation Configuration Control • Evaluation, coordination, approval or disapproval, and implementation of changes to configuration items after formal establishment of their configuration identification
- 28. Configuration Management © 2003 IBM Corporation 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
- 29. Configuration Management © 2003 IBM Corporation 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
- 30. Configuration Management © 2003 IBM Corporation Requirements of Configuration Management
- 31. Configuration Management © 2003 IBM Corporation CM Requirements • Identification of Configuration Items • Establishment of Baselines • Document control • Version control • Management of Workspaces • Creation of Builds • Backup & Archival • Management of Changes to Baselined Configuration Items • Status Accounting • Configuration Audits
- 32. Configuration Management © 2003 IBM Corporation Configuration Items and Baselines • Configuration Item - An aggregation of software, documents and data that is treated as a single entity in the configuration management process There are 3 types of CIs: Baselined – Formally reviewed and agreed document/source code, which is basis for, further development. E.g. Requirement specification document, design document etc. Controlled and Managed – Documents describing the admin and project Management activities. E.g. Project management plan, task allocation and project schedule documents, coding or GUI guidelines Controlled – Documents obtained from the customer which are not managed by us. E.g. reference technical material.
- 33. Configuration Management © 2003 IBM Corporation What is Baseline? - A item that has been formally reviewed and agreed upon, that thereafter serves as the basis for further development, and that can be changed only through formal change procedures
- 34. Configuration Management © 2003 IBM Corporation Configuration Items & Baselines - Typical Scenario • Definition Baseline - Created at the end of Requirement Specifications. Typical configuration items (CI) - - Requirement Specifications - Project Plan - Design Standards / Guidelines - Acceptance Test Plan • Design Baseline - Created at the end of Design. Typical CIs - - System Design Specification - Program Specification - Data Base Design - Coding Standards - System Test Plan - User Manual - User Interface Standards - Testing Standards
- 35. Configuration Management © 2003 IBM Corporation • Code / Unit Test Baseline - Created at the end of coding and unit. Typical configuration items (CI) - - source code - object code - unit test data / scripts • Testing Baseline - Created at the end of system testing . Typical CIs - - System test data - system test scripts - operations manual - installation manual
- 36. Configuration Management © 2003 IBM Corporation Definition Baseline Creation - A schematic Individual workspaces Internal review changes Definition Baseline Internal review Workspace Customer Review Workspace Formal change management procedures become applicable Configuration Audit Review Log Review Log
- 37. Configuration Management © 2003 IBM Corporation Document control Document Control procedure ensures the traceability of all the documents. It involves the following tasks: • Defining the naming scheme. • Updating Document Record List (DCR) of the documents to reflect the changes and assigning of version and release nos. • Provides usage of the documents by giving access rights to different folders. MyName is Mr.Unique
- 38. Configuration Management © 2003 IBM Corporation Version A variant of some artifact; later versions of an artifact typically expand on earlier versions. Version Control Version Control ensures the ability to reproduce any version of the software at any given time. It controls versions of source code, executables and documents .It provides version change history to ensure trace-ability. A1 A2 A3A4
- 39. Configuration Management © 2003 IBM Corporation An operational version of a system or part of a system that demonstrates a subset of the capabilities to be provided in the final product.
- 40. Configuration Management © 2003 IBM Corporation Work space management Workspaces refer to ‘private’ areas where developers can implement and test code in accordance with the project’s adopted standards in relative isolation from other developers.
- 41. Configuration Management © 2003 IBM Corporation Uncertainty is the only certain in this world. Why Backup?
- 42. Configuration Management © 2003 IBM Corporation Change Control
- 43. Configuration Management © 2003 IBM Corporation I can make the change directly in the baseline copy. Its just a one line change, so I don’t want to fool around with Change Request, check- out, check-in, etc
- 44. Configuration Management © 2003 IBM Corporation Change Control • Record of changes • Approval of change requests after analysing impacts (impact on retest & review, think it as another proposed) • Maintaining of baselines • Traceability between changes and change requests and vice versa IEEE Definition An element of configuration management, consisting of the evaluation, coordination, approval or disapproval, and implementation of changes to configuration items after formal establishment of their configuration identification
- 45. Configuration Management © 2003 IBM Corporation Change Management Process Change request documented Change request Evaluated Change request reviewed for approval CCB approved Change order prepared Configuration items, tasks, QC required is documented Configuration items checked out Change made; QC activities carried out Configuration audit carried out Changed items carried out New product release made Pending rejected
- 46. Configuration Management © 2003 IBM Corporation Change Request XYZ Software Corp. Change Request Project: Initiated By: Date: Description of Change Requested: Benefits Expected: Signature of Initiator: Attachments: Evaluated by: Change Request No. Technical Impacts: Estimates for costs and schedule Signature of evaluator: Attachments Date: Approving Auth Signature Date Recommendations Change Order Number
- 47. Configuration Management © 2003 IBM Corporation
- 48. Configuration Management © 2003 IBM Corporation Change Control Board (CCB) • Also called Configuration Control Board • A group of people responsible for evaluating and approving and disapproving proposed changes to configuration items, and for implementation of approved changes. • Typical CCB members - Project Manager - User Representative - Quality Controller - Configuration Controller
- 49. Configuration Management © 2003 IBM Corporation Some Good Practices • Keep version history in the configuration item. • Item to contain exact item name, version number, date • Identify configuration items to be tracked • Code should have history in the comment • Highlight the changes in the document atleast for two versions.
- 50. Configuration Management © 2003 IBM Corporation Configuration Audit
- 51. Configuration Management © 2003 IBM Corporation Configuration Audits • To ensure that what has been built is in conformance with what was required (original specifications and change requests) by analysing : - Test reports - review reports - change logs Definition Verification of a configuration item’s compliance with its configuration identification
- 52. Configuration Management © 2003 IBM Corporation Status Accounting An ounce of derivation is worth a pound of analysis - Wayne Babich
- 53. Configuration Management © 2003 IBM Corporation Configuration Status Accounting & Reporting • Keep track of - Current identification of items - Configuration of delivered software - Status of change requests / problem reports - Status of approved changes IEEE Definition An element of configuration management, consisting of the recording and reporting of information needed to manage a configuration effectively
- 54. Configuration Management © 2003 IBM Corporation Typical Information Baseline Library Items / Units Baseline Units Release Release Units Change OrderBackup Backup Units Check-in / Check-out Change Request/ Problem Log
- 55. Configuration Management © 2003 IBM Corporation Standard Reports • Summary list Change Requests / Problem Reports • List of CR / PR pending approval • Summary list of Change Orders • List of Change Orders pending completion • Items and versions of a Baseline • Current set of units in the library • List of changes since Baseline • List of checked-out items • History of backups • History of releases • List of items / versions in a baseline • List of items / version in a release
- 56. Configuration Management © 2003 IBM Corporation Typical Uses of the Configuration Accounting Data • In which backup is version 1.6 of P13? • What are the program level changes between release 5.1 and 5.2? • Which programs were replaced in release 5.2? • Which items were changed for Change Order 671? What were the versions of the units before and after the change? Have all the changes been incorporated and checked-in?
- 57. Configuration Management © 2003 IBM Corporation
- 58. © 2003 IBM Corporation Can we make SCM happen?
- 59. Configuration Management © 2003 IBM Corporation Thank You