IEEE/EIA 12207 
Software Life Cycle Processes
Prepared by: 
James W. Moore, moorej@ieee.org  
The MITRE Corporation 
January 1998

Unit 2 - ISO/IEC 12207
- History
- Purpose of 12207
- History of 12207
- Key concepts
- ISO/IEC 12207 processes

Purpose of 12207
- To establish a common framework for the life cycle of software
- Acquire, supply, develop, operate, and maintain software
- Undertakes broader scope than previous standards
- Manage, control, and improve the framework
- Recognizes that software is part of a system and that a project is part of an enterprise
- To establish a basis for world trade in software

Motivations for 12207
Previous standards ...
- … focused on the single contract or project in isolation
- … described a single monolithic process
- … failed to encourage investment in the discipline and capitalization of processes
- … induced 20-50% added costs in documentation and formal reviews

Unit 2 - ISO/IEC 12207
- History
- Key concepts
- ISO/IEC 12207 processes

Key concept of ISO/IEC 12207: 
Process/activity/task hierarchy
- Processes are subdivided into cohesive activities.
- Activities are subdivided into tasks.
- You may think of tasks as being the specifications for the execution of an activity.
- A task may be a self-declaration of intent, a requirement, a recommendation, or a permissible action.

Key concept of ISO/IEC 12207: Processes and parties
- Identification of processes is based on two principles:
- Modularity: Processes should be cohesive and should have low coupling to other.
- Responsibility: Each process should be executable by a single party.
- A particular organization may become the party responsible for executing a process

Key concept of ISO/IEC 12207: Continuing responsibilities
- The activities and tasks of a 12207 process are not steps to be performed.
- 12207 does not require that the activities and tasks are to be performed in any particular order.
- The activities and tasks of 12207 are continuing responsibilities whose execution is assigned for the duration of the process.

Key concept of ISO/IEC 12207: Categories of processes
- Primary: 
- Acquisition, Supply
- Development, Operation, Maintenance
- Supporting: processes used as “subroutines” by other processes
- Organizational: processes inherent to the organization and “instantiated” by the project
- Also, a special tailoring process

Key concept of ISO/IEC 12207: Integral evaluation
- Evaluation is not a distinct process or activity.
- Evaluation is treated as an internal, integral task of many activities in the standard.
- In general, the evaluations have stated purposes and stated criteria.
- Other processes may supplement internal evaluations: Verification, Validation, Joint Review, Audit, Quality Assurance, Improvement.

Key concept of ISO/IEC 12207: Temporal issues
- The standard does not specify a life cycle model, e.g. waterfall, spiral, etc.
- The standard does not place ordering dependencies or time dependencies on the tasks - that is the job of the chosen life cycle model and the project plan.
- Tasks may be iterated, repeated, recursively invoked, etc.

Key concept of ISO/IEC 12207: Approach to documentation
- The standard requires some outputs to be documented.
- The standard does not prescribe format, media, or content of the documentation.
- The Documentation Process permits the user to make these decisions.

Key concept of ISO/IEC 12207: Approach to baselining
- Standard differentiates between items and configuration items (CI). The CM process can handle both, but the latter are handled more rigorously.
- A baseline is a formally approved version of a CI. Baselines (as clarified by the IEEE/EIA version) are established by the primary processes, not by the CM process.

Unit 2 - ISO/IEC 12207
- History
- Key concepts
- ISO/IEC 12207 processes

ISO/IEC 12207 processes
- Primary
- Supporting
- Organizational

ISO/IEC 12207 processes: 
Primary processes
- Acquisition
- Supply
- Development
- Operation
- Maintenance 

ISO/IEC 12207 processes: Supporting processes
- A supporting process supports another process as an integral part with a distinct purpose:

ISO/IEC 12207 processes: Organizational processes
- Organizational processes inherently exist outside the scope of the project but instances of them are employed by the project:
- Management
- Infrastructure
- Improvement
- Training 

ISO/IEC 12207 processes: Tailoring process
- A special case
- The tailoring process is used to tailor the standard for usage on a particular project.
- Tailoring permits deletion of any process, activity or task.
- (Tailoring is discouraged in the IEEE/EIA adaptation of the standard.)