SEN: Configuration Management

Why we need configuration management?
- Need to redo the same product.
- Need for the mastering the development of complex system.
Objectives
- To know the physical and functional description of the product, its components and the associated supporting elements.
- To enable each participant to use coherent and validated data.
Definitions
- Product – Result of process, there are 4 generic product categories:
  - Services
  - Software
  - Hardware
  - Processed materials (e.g. lubricant)
- Product tree – Hierarchical structure depicting the product orientated breakdown of the project orientated breakdown of the project into successive levels of detail down to the configuration items.
- Configuration – Functional or physical characteristics of a product defined in configuration definition documents subject to configuration baseline.
- Configuration item – Aggregation(การรวมกัน) of hardware, software, processed materials, services or any of its discrete portions, that is designated for configuration management and treated(ปฏิบัติ, รักษา)
  as a single entity in the configuration management process.
  
  ** Configuration item can contain other configuration item(s).

The configuration item (เริ่มเจาะรายละเอียด)
- Starting point = the product tree
  - Breakdown of the system down to a level allowing
  - Each subsystem is seen as a black box by the other ones.
  - It is the kernel of the project structure and serves as main input for:
    - Configuration Management
    - Work Breakdown Structure
- Configuration items selection:
  - Identification of the products that will be retained as configuration item.
  - The configuration items are identified at different levels of the product tree.
  - When a product has been selected as a configuration item, its father in the product tree is necessarily a configuration item.
  - The selection of the configuration items shell be performed in the same time than the WBS preparation because a configuration item has an influence on the WBS: reviews, documents deliveries, schedule…
- Configuration items selection criteria:
  - Is the product critical from a safety, schedule or financials point of view?
  - Will the product require development of a new design or a significant (อย่างสำคัญ) modification to an existing design?
  - Does the product incorporate new or unproven technologies?
  - Does the product have an interface with hardware or software developed under another contract?
  - Is the item required for logistic support or activity?
  - Do all components of the product have common mission, installation and deployment requirements, common testing and acceptance?
Configuration baselines: Approved status of requirements and design of product at project key milestone that serves as reference for activities the life cycle of the product.

Product lifecycle
System analysis -> Preliminary Definition -> Detailed Definition -> Production -> Utilization
- The configuration baselines are supported by the product lifecycle.
- Established at PRR (Preliminary Requirements Review)
- Based on the URD (User Requirements Documents)
- Functional Configuration Baseline
  - Established at SRR (System Requirements Review)
  - Based on the TRD (Technical Requirements Document)
- Development Configuration Baseline
  - Established at PDR (Preliminary Design Review)
  - Based on : Internal architecture
  - URD of the products of the next lowest level, including interfaces.
- Design baseline
  - Established at CDR (Critical Design Review)
  - Based on: Approved design of the product.
  - Tests specifications and procedures.
- Product configuration baseline
  - Established at QR (Qualification Review) & AR (Acceptance Review).
  - Based on: All the data necessary for production, acceptance, operation, support and disposal.
- The configuration baseline is formally established:
  - Review data package -> Prior to the review, the documentation is sent to the customer and/or to a review team.
  - The customer/review team will formalize his comments by using a dedicated form: RID (Review Item Discrepancy)
As designed and as built configurations
- Link between configuration baselines and as-designed configuration.
- As designed configuration is composed of the last approved baseline and all the departure approved since the last baseline establishment.
- What is a change?
  - Agreed evolution of a configuration baseline.
  - A change may be originated by
    - An anomaly.
    - An evolution of the need.
    - A bad understanding of the need.
    - A feasibility problem.
- What is a deviation?
  - Permission to depart from the originally specified requirements for a product prior to realization.
    ** Note: A deviation permit is generally given for limited quantity of product or period of time, and for a specific use.
  - What is a Waiver (or concession)?
    - Permission to use or release a product that does not conform
      (เหมือนหรือคล้ายกัน) to specify requirements.
The Configuration Control Board (CCB) is a regular meeting aiming at providing all the decisions related to the treatment
(การดูแล, การทำให้คืนสภาพ) of the changes and departures.
Identification marking: Each item, H/W and S/W is uniquely identified by a specific identification code.
- This identification code allows distinguishing a product during its entire lifecycle.