Remarks: This Software Architecture Specification is part of the SafeQP Certification Kit↑, but applies to the whole QP/C Framework family↑. This document is the best source of information about the master plan for the overall organization of QP/C Framework as well as QP/C Applications derived from the framework. The detailed QP/C Framework design is described in a separate document: QP Software Design Specification [DOC_SDS_QP].

Revision History

QP/C version	Document revision	Date (YYYY-MM-DD)	By	Description
7.3.4	A	2024-05-05	MMS	Initial release for IEC-61508 SIL-3 and IEC-62304 Class-C.
7.4.0	B	2024-07-30	MMS	Updated for QP 7.4.0.
8.0.0	C	2024-11-17	MMS	Updated for QP 8.0.0.
8.1.2	D	2025-12-09	MMS	Updated for QP 8.1.2.

About this Document

DOC_SAS_QP

Software Architecture Specification (SAS)

Description
This Software Architecture Specification (SAS), with Unique Identifier: DOC_SAS_QP, describes the software architecture of QP/C Framework that satisfies the QP Software Requirements Specification (DOC_SRS_QP) and the QP Software Safety Requirements Specification (DOC_SSRS_QP).

Note: The architecture specified in this document can be ultimately implemented in various programming languages, so this document applies to a whole family of QP/C Real-Time Event Frameworks (RTEFs), currently consisting of QP/C, QP/C++_, __SafeQP/C, and SafeQP/C++ frameworks implemented in C and C++, respectively. Other possible implementations (e.g., QP/Rust) of these requirements and features might be added in the future.

Concerns
This architecture specification addresses the following general concerns (understood here as topics of interest [ISO-42010:2022]):

the applied programming paradigms and software technologies;
the context, layering, and assignment of functionality to QP/C Framework and QP/C Application;
the interface between the QP/C Framework and the QP/C Application based on the framework, as well as between the QP/C Framework and the Operating System underlying the framework;
main policies concerning resource management and ownership.

Architectural Viewpoints
The QP/C Framework architecture is presented according to the international standard [ISO-42010:2022] Architecture Description by means of the following architectural viewpoints (each consisting of various architectural views):

Audience
This Software Architecture Specification is primarily intended for the following stakeholders:

Application Developers who develop QP/C Applications based on the QP/C Framework,
Software Architects,
Quality-Assurance Engineers,
System Engineers,
Test Engineers, as well as
Managers who oversee the software development.

Backward Traceability

FSM_QP_SDLC_02: Step-2 of the QP/C Framework SDLC shall review and update Software Architecture Specification (SAS).

Document Conventions

Architecture Specification UIDs

For traceability, this Software Architecture Specification uses the Unique Identifiers (UIDs) with the following structure:

 +---------------- [1] Work artifact class (e.g., 'SAS' for Software Architecture Specification)
 |  +------------- [2] Project identifier ('QP' for @QPX Framework or 'QA' for @QPX Application)
 |  |   +--------- [3] Architecture view (e.g., 'OSAL' for OS Abstraction Layer)
 |  |   |
SAS_QP_view

Examples: SAS_QP_OSAL, SAS_QP_OOA

UML Semantics

Most diagrams presented in this Software Architecture Specification conform to the established and precisely defined semantics of the Unified Modeling Language [UML2.5:17]. In case a diagram uses any non-normative" elements, the semantics of those are explained in the diagram description.

References

[ISO-42010:2022]	ISO/IEC/IEEE, "International Standard ISO/IEC/IEEE 4210, Software, systems and enterprise engineering - Architecture description", 2022
[IEC 61508-1:2010]	IEC 61508-1:2010 Functional safety of electrical/electronic/programmable electronic safety-related systems- Part 1: General requirements
[IEC 61508-2:2010]	IEC 61508-2:2010 Functional safety of electrical/electronic/programmable electronic safety-related systems- Part 2: Requirements for E/E/PE safety-related systems
[IEC 61508-3:2010]	IEC 61508-3:2010 Functional safety of electrical/electronic/programmable electronic safety-related systems- Part 3: Software requirements
[IEC 61508-4:2010]	IEC 61508-4:2010 Functional safety of electrical/electronic/programmable electronic safety-related systems- Part 4: Definitions and abbreviations
[IEC 61508-7:2010]	IEC 61508-7:2010 Functional safety of electrical/electronic/programmable electronic safety-related systems- Part 7: Overview of techniques and measures
[ISO 26262-1:2018]	ISO 26262-1:2018(en) Road vehicles — Functional safety — Part 1: Vocabulary. International Standardization Organization.
[ISO 26262-2:2018]	ISO 26262-2:2018(en) Road vehicles - Functional safety - Part 2: Management of functional safety. International Standardization Organization.
[ISO 26262-3:2018]	ISO 26262-3:2018(en) Road vehicles - Functional safety - Part 3: Concept phase. International Standardization Organization.
[ISO 26262-4:2018]	ISO 26262-3:2018(en) Road vehicles - Functional safety - Part 4: Definitions and abbreviations. International Standardization Organization.
[ISO 26262-6:2018]	ISO 26262-6:2018(en) Road vehicles - Functional safety - Part 6: Product development at the software level. International Standardization Organization.
[ISO 26262-8:2018]	ISO 26262-8:2018(en) Road vehicles - Functional safety - Part 8: Supporting processes. International Standardization Organization.
[DOC_SRS_QP]	Software Requirements Specification
[DOC_SSRS_QP]	Software Safety Requirements Specification
[DOC_SDS_QP]	Software Design Specification
[QM-Tool:2024]	Quantum Leaps, QM Model-Based Design Tool↑
[OO-in-C:2023]	Object-Oriented Programming in C↑, Quantum Leaps, GitHub, 2023
[UML2.5:17]	"OMG Unified Modeling Language (OMG UML) Version 2.5.1", document formal/2017-12-05, OMG 2017

Safety Viewpoint