News & Press

Green Hills Software Introduces the First Commercial High Assurance, Crash-Safe File System

Partitioning, Journaling File System (PJFS) Meets Most Stringent Reliability, Safety and Security Requirements


SANTA BARBARA, CA—November 14, 2005—Green Hills Software, Inc., the technology leader in operating systems and software development tools for safe and secure systems, introduced today its Partitioning, Journaling File System (PJFS). PJFS is a crash-safe file system designed for safety, security, and reliability-critical systems. Due to its high assurance design, PJFS has a very small footprint, making it ideal for embedded applications, yet it also scales to desktop and server system requirements. PJFS is supported with Green Hills Software royalty-free INTEGRITY operating system and velOSity microkernel.

“Almost everyone has been victimized by a file system failure, with the implications ranging from slow boot times while the disk is checked to corrupt or lost data,” commented David Kleidermacher, vice president of engineering for Green Hills Software. “While failures may be annoying and time consuming when they afflict our personal computers, they can have calamitous consequences in security-critical and safety-critical applications. Our new PJFS overcomes the limitations and liabilities of traditional file systems and is the first file system suitable for high-assurance applications.”

PJFS is based on a simple and elegant design in accordance with the Multiple Independent Levels of Security (MILS) security architecture. This makes it suitable for evaluation at the highest levels of assurance. PJFS' patent-pending quality of service architecture enables applications at varying criticality levels to have guaranteed file storage resources, even when sharing a single physical device.

PJFS provides complete journaling (data and metadata) for crash safety and fast reboot/recovery. This makes it ideal for systems such as avionics, automotive, telematics, infotainment and medical devices, as well as consumer devices where data integrity and fast startup are critical requirements.

Other PJFS features include:

  • A familiar, POSIX-compliant application programming interface (e.g. open, close, read, write, etc.) makes it easy to use for new applications as well as retargeting of legacy software. The programming interface also includes lightweight extensions for non-blocking reads and writes.
  • An optional ARINC 653 file system interface for safety-critical avionics systems.
  • A flexible back-end design enables use with unlimited media types (disk, flash, etc.). Included are built-in back-ends for RAM disks, IDE-based devices, and flash memory using Green Hills Software’s fault tolerant, wear-leveling block manager with background garbage collection that is ideal for computer systems with limited lifetime, solid state storage (both NOR and NAND devices are supported).

PJFS along with FFS, DOS/FAT/FAT32, ISO9660 (CDFS), UDF, and NFS fills out a comprehensive suite of file system choices for INTEGRITY and velOSity systems.


PJFS is being used today by several Green Hills Software customers. General availability is planned for January, 2006.

About Green Hills Software

Founded in 1982, Green Hills Software, Inc. is the technology leader in Real-Time Operating Systems (RTOS) and Device Software Optimization (DSO) 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, the Green Hills logo, MULTI, INTEGRITY, velOSity, AdaMULTI and TimeMachine, are trademarks or registered trademarks of Green Hills Software, Inc. in the U.S. and/or internationally. All other trademarks 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
Tel: 805-965-6044

Green Hills Software, Inc.
Barbel French
Tel: 805-965-6044