Integrity (operating system)

Integrity (operating system)
Name	Integrity
Developer	Green Hills Software
Family	Real-time operating systems
Working state	Current
Source model	Commercial proprietary
Latest release	Multiple variants
Kernel type	Microkernel (separation kernel)
Supported platforms	ARINC 653, x86, ARM, PowerPC, MIPS, RISC-V
License	Proprietary
Website	greenhills.com

Integrity (operating system) is a commercial real-time operating system developed by Green Hills Software for safety-critical and security-critical embedded systems. It is designed as a high-assurance separation kernel and certified for use in avionics, automotive, industrial control, and defense applications, emphasising determinism, partitioning, and formal certification. Integrity has been adopted in systems certified against standards such as DO-178B/C, ISO 26262, Common Criteria, and ARINC 653 profiles.

Overview

Integrity is a high-reliability RTOS offering spatial and temporal partitioning, deterministic scheduling, and a small trusted computing base, intended for use where certification against Federal Aviation Administration guidance, European Union Aviation Safety Agency, International Organization for Standardization standards, or National Institute of Standards and Technology-referenced frameworks is required. Green Hills positions Integrity alongside other safety-focused platforms used by The Boeing Company, Airbus, Lockheed Martin, General Motors, and Bosch within avionics, automotive, and industrial ecosystems. The product suite integrates with development toolchains from vendors like Intel, ARM, NVIDIA, Texas Instruments, and tool suppliers including Wind River Systems-based environments.

Architecture and Design

Integrity uses a separation-kernel microarchitecture inspired by research from Mitre Corporation and principles advocated by John Rushby and National Security Agency evaluation practices. The kernel enforces partitioning comparable to ARINC 653 partitions used by Collins Aerospace and Thales Group platforms, while supporting symmetric multiprocessing on multicore hardware from Intel Corporation and Advanced Micro Devices. Integrity provides fixed-priority and time-slice scheduling modes influenced by Liu and Layland real-time scheduling theory and integrates inter-partition communication mechanisms following design patterns similar to those in Lynx Software Technologies and QNX Software Systems products. Its microkernel minimizes attack surface, aligning with concepts from Peter Neumann and formal methods promoted by AdaCore and SPARK Ada advocates.

Security Features and Certifications

Integrity achieves evaluations under Common Criteria Protection Profiles and has been used in systems certified to DO-178C Design Assurance Level A, ISO 26262 ASIL D, and IEC 61508 SIL 3/4 contexts. Security features include separation enforced by a separation kernel, Mandatory Access Control patterns akin to those in SELinux discourse, and support for secure boot chains leveraging roots of trust from Trusted Computing Group and TPM implementations. Integrity has been deployed in environments that require compliance with guidance from U.S. Department of Defense, European Defence Agency, and procurement frameworks used by NATO members. Certification attestations often reference evaluation labs such as NIAP and independent testing by organizations like UL and TUV Rheinland.

Development History and Versions

Green Hills introduced Integrity in the 1990s and evolved it through successive releases to address multicore and mixed-criticality requirements important to stakeholders including Raytheon, Northrop Grumman, Siemens, and Daimler AG. Major milestones include adoption of ARINC 653 profiles for avionics integrators such as Rockwell Collins, integration with virtualization techniques used by VxWorks integrators, and expansions to support architectures championed by RISC-V International members. The platform’s roadmap has paralleled industry shifts noted by organizations like SAE International and standards bodies including IEEE committees, while toolchain support aligned with compilers and debuggers from GCC and proprietary suites by Green Hills.

Deployment and Use Cases

Integrity is used in certified flight control systems on platforms by Boeing and Airbus subcontractors, in autonomous vehicle stacks for automotive tier-1 suppliers like Continental AG and ZF Friedrichshafen, and in industrial control systems deployed by Siemens AG and Schneider Electric. Defense customers such as BAE Systems and General Dynamics have integrated Integrity into mission systems, while space agencies like NASA and contractors participating in European Space Agency projects have explored Integrity for mission-critical payloads. Use cases often require integration with middleware and frameworks from ARINC, FACE Consortium, OSEK/VDX-aligned initiatives, and communications stacks from Cisco Systems and ETSI profiles.

Performance and Reliability

Integrity emphasizes low-latency interrupt handling, deterministic context-switch times, and bounded scheduling jitter suitable for hard real-time workloads demanded by DO-178C avionics applications and IEC 61508 industrial controls. Benchmarks cited by Green Hills compare context-switch and inter-process communication latencies against commercial RTOS offerings from Wind River and QNX, and scalability studies reference multicore behavior on processors by Intel and ARM. Reliability claims align with fielded systems in avionics and automotive domains operated by companies like Embraer and Toyota Motor Corporation, with lifecycle support and long-term maintenance programs paralleling practices at Siemens and Honeywell.

Reception and Comparisons with Other RTOS

Industry analysts and integrators compare Integrity with other high-assurance RTOS such as products from Wind River Systems, QNX Software Systems, Lynx Software Technologies, and open-source alternatives like Linux Foundation-hosted projects. Evaluations often focus on certification readiness, partitioning robustness relative to ARINC 653 implementations, and the total cost of ownership versus communities supporting Android Open Source Project or Yocto Project-based stacks. Customers in defense and aerospace frequently choose Integrity for its certification pedigree, while commercial vendors weigh trade-offs against virtualization-focused solutions from VMware and container orchestration trends promoted by Cloud Native Computing Foundation.

Category:Real-time operating systems