BS ISO IEC IEEE 24774:2021 pdf free download – Systems and software engineering – Life cycle management – Specification for process description
There is no fixed dividing line between what constitutes a process and what is considered as a sub-process or an activity within a process. Typically, processes are achieved through the performance ofactivities comprising groups of related tasks.A significant activity of interest with numerous tasks canalso be described as a process if it were useful to treat the activity of interest in detail. The limits of aprocess generally are determined by the production of a major output and outcomes, rather than theintermediate outputs produced by activities within the process. Additionally, if processes are highlyautomated and require little human control or intervention, it can be appropriate to combine severalprocesses into one process description.
NOTE1 Often a set of processes are developed; and some processes are decomposed into more than one level.However, decomposition of processes into more than three levels is likely to be confusing and hard for humans touse.
Procedures differ from process descriptions in that procedures are written in steps to be followed inorder.Procedures can be written as instructions to the persons performing the procedure. Procedurescan also be written to assist an evaluator or auditor to understand the procedure, especially its controlsor outputs.
NOTE2 ISO/IEC/IEEE 82079-1 provides detailed requirements for writing instructions.
Required activities are stated in process descriptions using either the imperative (as a command),or asa ‘shall’ statement.
NOTE3 Annex A shows different examples of the expression of mandatory/required process elements as usedin sample process descriptions.
Complete processes generally involve several types of generic activities (Table 1).
Generally, several software or systems engineering processes are performed concurrently during a lifecycle stage.However, concurrent activities (e.g.installation and quality assurance inspections) are notnecessarily part of the same process, since their purpose, resources, methods, outputs, and outcomesare different.
Process descriptions may be used either to describe generic processes (for example “projectmanagement process”) or to describe a particular instance of a generic type (for example “projectmanagement process for project A'”).For specific process descriptions, generic process descriptionsmay be instantiated with respect to roles or responsibilities, resources, required inputs and outputs,constraints and controls, and time.Annex A provides examples of process descriptions used to developa process model.Annex B provides a technique for demonstration of process traceability betweenelements, using an example process from Annex A.
Processes are often combined to form a process model (framework of related processes).ISO/IEC/IEEE 15288 and ISO/IEC/IEEE 12207, for example, provide life cycle process reference modelsfor ‘systems and software in which outcomes are defined and activities grouped for generic life cycleprocess description. Based on ISO/IEC/IEEE 15288:2015，Annex A and ISO/IEC/IEEE 12207:2017,Annex A, organizations or projects can apply process tailoring to suit the nature of the effort.
NOTE4 ISO/PAS 19450 specifies concepts,semantics, and syntax of Object-Process Methodology as amodelling paradigm and language for producing conceptual models at various extents of detail.
Various schemas for characterizing and evaluating process maturity, capability or quality are in use.These schemas typically distinguish between levels of process performance and involve processimprovement. Process levels can involve following the process repeatedly to successfully achieve itsoutcome or produce specified output, and automating and improving the process. The choice of detailsin the process description can be used to characterize the process description at a certain level ofprocess maturity, capability or quality.
NOTE5 ISO/IEC 33020 defines a process measurement framework for the assessment of process capability.