News & Press

Green Hills Software Introduces INTEGRITY PC,
Enabling the Integration of Linux and Other Legacy
Software into Secure Systems

New Virtualization Solution Deployed by Boeing in Military Hardware

SANTA BARBARA, CA—November 29, 2004
Green Hills Software, Inc., the market leader in safety-critical and royalty-free Real-Time Operating Systems (RTOS), today announced
the immediate availability of INTEGRITY® PC, an extension to the company’s INTEGRITY operating system that enables the incorporation of legacy applications and traditional operating systems, such as Linux, into high-security and high-reliability applications.
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Boeing is using INTEGRITY PC to take advantage of existing Linux-based software. With INTEGRITY PC, Boeing engineers did not have to port their Linux code to a secure operating system and they can easily incorporate updates to the Linux-based code.

INTEGRITY PC integrates the INTEGRITY operating system with Green Hills Software’s new Padded Cell™ secure virtualization technology. The Padded Cell technology implements a “virtual computer” in a user-mode application running on top of the INTEGRITY operating system. Multiple Padded Cell applications can run concurrently on a single physical computer, each hosting its own guest operating system. An impenetrable wall around each virtual computer ensures that errant, insecure or malicious code can never compromise the security or reliability of the rest of the system—either inadvertently or via a hostile attack.

“Like a padded cell, INTEGRITY PC prevents Linux, non-memory-protected operating systems such as Wind River’s legacy VxWorks, and other insecure and unreliable software from harming the rest of a system while also limiting the harm it can do to itself,” explained Dan O’Dowd, founder and chief executive officer of Green Hills Software. “For years, the INTEGRITY operating system has lead the market for security-critical and safety-critical applications, including leading-edge avionics and defense applications. Now, with INTEGRITY PC, users of enterprise operating systems can upgrade to a secure foundation without having to re-implement their existing applications. Legacy operating systems and applications can safely co-exist with totally reliable and security-critical applications running natively under the INTEGRITY operating system.”

Key Features and Problems Solved

Key features and security threats addressed by INTEGRITY PC include:
  • Guest operating systems and their applications run as “user mode” INTEGRITY applications, which means that they cannot alter the hardware’s configuration. This prohibits them from circumventing the protections imposed by the INTEGRITY operating system.
  • Hardware memory protection prevents software running within a virtual computer from reading or writing memory not explicitly allocated to it. Even if a virtualized application were contaminated by a buffer overrun exploit, hacker, virus, worm or Trojan horse, it would not be able to corrupt, disrupt or spy on any other part of the system. Moreover, a hacker cannot leverage a break-in of software running in one virtual computer to gain access to the rest of the system.
  • All Input and Output (I/O) operations can be monitored, including network communications. This allows aberrant activity, such as that generated by spyware and hackers, to be detected and filtered. Because the monitoring function is performed by a native INTEGRITY application, it cannot be subverted or disabled by software running under a guest operating system.
  • Guaranteed resource availability provides each virtual computer and native INTEGRITY application with the processor bandwidth and memory required for successful execution. No software can exhaust the resources needed by another application or by the INTEGRITY operating system—thwarting any denial of service attack.
  • Completely deterministic, real-time performance is provided by the INTEGRITY operating system, enabling the co-existence of real-time and general-purpose applications.
  • Green Hills Software’s Integrate tool allows users to graphically configure and visualize a system’s security, such as the allocation of resources to an application, the devices that an application can access, and which applications can communicate with each other.

Flexible Interfaces

INTEGRITY PC supports the simultaneous use of multiple system interfaces, for maximum developer and user flexibility:
  • The use of one or more guest operating systems provides binary compatibility with existing applications, no re-compilation is needed. Multiple instances of the same or different operating systems can run concurrently in different virtual computers, allowing programs to be compartmentalized for increased security.
  • POSIX interfaces provide source code portability with UNIX and Linux applications together with the reliability and security benefits of the INTEGRITY operating system. The INTEGRITY operating system is the first and only operating system to be certified under the “POSIX®: Certified by IEEE and The Open Group” program to the 1003.1™-2003 System Interfaces Product Standard and is listed on the certification register at
  • INTEGRITY interfaces offer full access to the operating system’s underlying security and real-time performance capabilities.


INTEGRITY PC running on PowerPC processors with support for Linux as a guest operating system is available today. Please contact Green Hills Software for availability information for other target processors and guest operating systems.

About Green Hills Software

Founded in 1982, Green Hills Software, Inc. is the technology leader for real-time operating systems and software development tools for 32- and 64-bit embedded systems. Our royalty-free INTEGRITY RTOS, velOSity microkernel, compilers, MULTI and AdaMULTI Integrated Development Environments and TimeMachine debugger, offer a complete development solution that addresses both deeply embedded and high-reliability applications. Green Hills Software is headquartered in Santa Barbara, CA, with European headquarters in the United Kingdom. Visit Green Hills Software on the web at

Green Hills Software, the Green Hills logo, MULTI, INTEGRITY, velOSity, AdaMULTI, TimeMachine, Padded Cell, Integrate and EventAnalyzer are trademarks or registered trademarks of Green Hills Software, Inc. in the U.S. and/or internationally. POSIX is a registered trademark and 1003.1 is a trademark of the Institute of Electrical and Electronic Engineers, Inc. All other trademarks and products are the property of their respective owners.

North American Sales Contact:
Green Hills Software, Inc.
30 West Sola Street,
Santa Barbara, CA 93101,
Tel: 805-965-6044
Fax: 805-965-6343

International Sales Contact:
Green Hills Software Ltd.
Fleming Business Centre
Leigh Road
Hampshire SO50 9PD
Tel: +44 (0)2380 649660
Fax: +44 (0)2380 649661


Media Contacts:
Green Hills Software, Inc.
Lynn J. Robinson
(805) 965-6044

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Green Hills Software’s INTEGRITY Operating System First to Be Certified Under the IEEE and The Open Group POSIX® Certification Program

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EE Times-Jun. 2004
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Avionics-Mar. 2004
Keeping Secrets in Integrated Avionics (pdf)
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