Prof. Yoram Reich, Faculty of Engineering, Tel Aviv University, 6/15/2006, [CM overview.doc] Configuration Management What is CM? CM processes in practice CM and organizational context CM technology Configurations How are versions created? Versions SCM vs. PDM CM : a process for maintaining the integrity of products as they evolve from specifications through design, development, production, maintenance, and even retrofit. Exercise the right level of CM: too little the product vanishes, too much no product is produced 1. CM processes in practice CM processes: 1. Planning 2. Identification 3. Change control 4. Status accounting 5. Audits Buckley figs: 1-2: overall process 2-1: result of planning: 4 last stages 1. Planning What will be managed (objects and attributes [identification, where used, when released, …])? In which format will be managed? What will be the management process? How a release is managed? 2. Identification Actually going and identifying all items to be managed. 3. Control Identify problem Review report 1 972-3-6407385 (tel), 972-3-6407617 (fax) email: yoram@eng.tau.ac.il, URL: http://or.eng.tau.ac.il:7777,
Prof. Yoram Reich, Faculty of Engineering, Tel Aviv University, 6/15/2006, [CM overview.doc] Determine cause Determine corrective action Propose changes (ECP-engineering change proposal) Evaluate changes Coordinate proposed changes Approve/disapprove proposed changes Implement approved changes 4. Accounting Identify reporting needs Establish/update CM database Produce status accounting reports 5. Auditing Functional configuration audits - configuration object's function (as-developed) adheres to specs. Physical configuration audits - configuration object's function (as-built) adheres to specs. Be able to track milestones and get back to a known stable configuration. Figures: Buckley figs: 2-6: example of a change to hardware caused by loading software 3-1: 4-1: 4-8: 9-1: 13-1: 14-1: 15-1: 15-2: Fruhauf (Dart) Fig 1 Table 1 2. CM and organizational context CM impacts development processes. It can intervene into or impair work. Consequently, any adoption of CM must address organizational issues (e.g., be adapted to the particular organization culture and practices), for example, an organization employing Rapid Application Development (RAD). RAD : Rapid Application Development Properties: New tasks emerge Developers work closely Quick prototyping cycles 2 972-3-6407385 (tel), 972-3-6407617 (fax) email: yoram@eng.tau.ac.il, URL: http://or.eng.tau.ac.il:7777,
Prof. Yoram Reich, Faculty of Engineering, Tel Aviv University, 6/15/2006, [CM overview.doc] No exhaustive testing SCM seems to slow down! Solutions: Add test stages as needed Develop less formal change management (tracking, notification, and incorporation) Work offline and reconcile changes Share completed and partial changes Share work areas Don’t stop developers’ work when product is being tested. 3. CM technology CM tools functionality: 1. Check-in/check-out process 2. History information 3. Version attributes 4. Possibility of finding differences between versions 5. Possibility of merging differences between two versions 6. Change and maintenance process (finding items belonging to a specific release, finding changes, ) 7. Scalability 8. Integration between CM and change request tools 9. Statistics and metrics (documentation size, # of changes, ) on saved data 10. Distributed development (multi-site development: replication of databases 11. Integration with software development environments 12. UI 13. Reliability We can use wiki technology to check these facilities. 4. Configuration 3 972-3-6407385 (tel), 972-3-6407617 (fax) email: yoram@eng.tau.ac.il, URL: http://or.eng.tau.ac.il:7777,
Prof. Yoram Reich, Faculty of Engineering, Tel Aviv University, 6/15/2006, [CM overview.doc] Figure 1 : Product and its assembly configuration A product could have several configurations: 1. As specified 2. As designed 3. As produced 4. As maintained Bridging these configurations is not an easy problem. Figure 2 : Different kinds of assemblies of documents and products as exemplified by mechanical and software engineering products. The configuration can hold all available information about the product. The structuring might not be based on physical location but on design phases. 4 972-3-6407385 (tel), 972-3-6407617 (fax) email: yoram@eng.tau.ac.il, URL: http://or.eng.tau.ac.il:7777,
Prof. Yoram Reich, Faculty of Engineering, Tel Aviv University, 6/15/2006, [CM overview.doc] Figure 3: Klunover Figure Figure 4 : Representations of a software product: objects and relations (compositional and dependencies) Figure 5 : Compositional modeling: from models (b) to instances (d). Figure (d) allows to represent (and obtain information) specific instances. 5 972-3-6407385 (tel), 972-3-6407617 (fax) email: yoram@eng.tau.ac.il, URL: http://or.eng.tau.ac.il:7777,
Prof. Yoram Reich, Faculty of Engineering, Tel Aviv University, 6/15/2006, [CM overview.doc] Figure 6 : Alternate and substitute relationships: Representing different variations of the product that are created during product design. Example of how configuration can be complicated and more informative. We have seen a number of examples showing that product description is composed of: Objects Relationships (compositional, dependencies) This reminds us of UML, knowledge level modeling in AI, and concept mapping. Figure 7 : Different views of the product/configuration. Different people may have access to only specific views. 6 972-3-6407385 (tel), 972-3-6407617 (fax) email: yoram@eng.tau.ac.il, URL: http://or.eng.tau.ac.il:7777,
Prof. Yoram Reich, Faculty of Engineering, Tel Aviv University, 6/15/2006, [CM overview.doc] 5. How are versions created? Figure 8 : versions, workspaces, and configurations. Versions are created by checking-in-out from the repository. The configuration must be explicit; otherwise, there are an exponential number of options among the variations. The configuration thread records particular combinations that are defined as available configurations. Figure 9 : Working with versions: version graph including offspring branches, parallel development and merging of branches. What is a version of a configuration? Different entities Same entities different versions 7 972-3-6407385 (tel), 972-3-6407617 (fax) email: yoram@eng.tau.ac.il, URL: http://or.eng.tau.ac.il:7777,
Prof. Yoram Reich, Faculty of Engineering, Tel Aviv University, 6/15/2006, [CM overview.doc] Different configurations Product space & version space : AND/OR graph. AND - composition of objects to system OR - alternative versions. Figure 10 : Product first - composition and then alternative versions. Version first - versions and their particular compositions. Intertwined - layers of ANDs and Ors (or vice versa) 8 972-3-6407385 (tel), 972-3-6407617 (fax) email: yoram@eng.tau.ac.il, URL: http://or.eng.tau.ac.il:7777,
Prof. Yoram Reich, Faculty of Engineering, Tel Aviv University, 6/15/2006, [CM overview.doc] Figure 11 : Example of configuration of software components: RCS: program with its parts versioned. At this time there is one consistent configuration shown in black. 6. Versioning Versioning: Basic definitions Version - a state of an evolving object Object : anything from complete product to atomic entity Object invariants : common to all versions Version difference : delta Figure 12 : Deltas: symmetric: difference in attributes, directed: sequence of modification steps. Extensional / Intensional versioning Extensional : A versioned item - a set of versions, no problem to construct versions. Intensional : for handling potentially large version space. The versioned item is { ( ) } = defined by a set of constraints that need to be fulfilled . A version is | V v c v constructed at the time of query. In the construction, consistency between version parts is enforced using a configurator. 9 972-3-6407385 (tel), 972-3-6407617 (fax) email: yoram@eng.tau.ac.il, URL: http://or.eng.tau.ac.il:7777,
Prof. Yoram Reich, Faculty of Engineering, Tel Aviv University, 6/15/2006, [CM overview.doc] Figure 13 : Intensional versioning with a configurator . Using a configurator is hard. In most cases, consistent configurations are created manually ( extensionally ) Method of keeping track of versions: State-based : applies to extensional versioning: keeping all states. Change-based : a change is a function from V to V. Therefore, a sequence of changes can be replayed to obtain subsequent version. Objects to be managed: Atomic objects: Files CAD models Versioned controlled individually: extensional versioning Versions - one of this is the present version Variants - several options that co-exist Composite-structured objects: a collection of atomic objects and other configurations Libraries Systems CAD Assemblies Versions are constructed using selection mechanisms/rules: intentional selection # of possibilities is combinatorial -> use automated mechanisms Intentional : 10 972-3-6407385 (tel), 972-3-6407617 (fax) email: yoram@eng.tau.ac.il, URL: http://or.eng.tau.ac.il:7777,
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