Configuration management

Reasons for software configuration management  it facilitates the ability to communicate  status of documents, coding, changes  released software can be an asset for other projects (reusability)  extreme example in object libraries  it enhances the ability to provide maintenance support  listing of software development  allocated time and budget

What is CM ?  A discipline applying technical and administrative direction and surveillance to :  Identify and document the functional and physical characteristics of a configuration item  Audit the configuration items to verify conformance to specifications, interfaces control documents,...  Control changes to configuration items and their related documentation  Record and report information needed to manage configuration items effectively, including the status of the proposed changes and the implementation status of the approved changes

Configuration item A configuration item is a collection of hardware, software and/or firmware, which satisfies an end-use function and is designed for CM. CM consists of four divisions : configuration management configuration identification configuration change control configuration status accounting configuration audits - to maintain the integrity of the products as they evolve - to support product development and maintenance - it is like buying an insurance

Definitions 2 Configuration management is the management procedure including:  Configuration identification  selection of documents that identify the configuration characteristics of an item  Configuration change control  controlling the changes to the configuration and its identifying documents  Configuration status accounting  recording implementation of changes to the configuration and the documents  Configuration audit  the checking of an item for compliance with the configuration identification Additional activities  Interface control  identifying all characteristics relevant to the interfacing of configuration items  Subcontractor control

CM-environment : general Configuration management Configuration change control Config. status accounting Configuration audits Definitions from: Implementing configuration management Fletcher J. Buckley IEEE-press 1992 Documentation Firmware Software Hardware

CM-environment : Definitions  Part, Item:One piece or several pieces joined together, that are not normally subject to disassembly  Subassembly : two or more parts that form a portion of an assembly, replaceable as a whole  Assembly : a number of parts or subassemblies, joined together to perform a specific function  Units : an assembly or any combination mounted together, normally capable of independent operation in various situations  Groups : a collection of units, assemblies or subassemblies that is a subdivision of a set or system, but not capable of performing a complete operational function  Set : put together to perform an operational function  Subsystem : combination of sets, groups and so on that performs an operational function within, and is a major division of, a system  System : A combination of parts assemblies and so on joined together to perform a specific operational function or functions.

Item identification  Hardware  manufacturers id-number, PIN-code, NSCM  Where-used problem  Software  file identifier  version description  Drawings, Documents

Item identification Each item must have a unique name and version  Is this the same system in which the fault has been reported ?  What are the constituent items of this system ?  The system worked yesterday ; what has changed ?  Why is the behavior of this item not consistent with the listing?  What is the status of this item ? Has it been tested ?  How did this item evolve to its present state ?

Version management  Provides answers to questions like:  How should the system be structured so that different systems can be build to meet the requirements of different users ?  How should an old version of the system be preserved, e.g. to investigate a fault ?  How can a version of the system be build so that it contains certain fixes but not others ?  How may two engineers work on the same item at the same time ?

Change control Addresses issues such as :  What will be the impact of a proposed change ?  Which faults are fixed in this version and which are outstanding ?  Has everyone with an interest in this item been informed on the change ?  Has the change been properly tested ?  Are there any changes planned for this item ?