What is POSIX®? POSIX is the Portable Operating System Interface, the open operating interface standard accepted world-wide. It is produced by IEEE and recognized by ISO and ANSI.

POSIX support assures code portability between systems and is increasingly mandated for commercial applications and government contracts. For instance, the USA’s Joint Technical Architecture—Army (JTA-A) standards set specifies that conformance to the POSIX specification is critical to support software interoperability.

Lynx Software Technologies has been committed to the POSIX standard for the past 20 years.

The LynxOS® real-time operating system is certified POSIX-conformant and also supports all of the routines in POSIX.1b and POSIX.1c.

POSIX CONFORMANCE IS WORTH MORE THAN POSIX COMPLIANCE

POSIX conformance is what real-time embedded developers are usually looking for. POSIX conformance means that the POSIX.1 standard is supported in its entirety. In the case of the LynxOS real-time operating system, the routines of the POSIX.1b and POSIX.1c subsets are also supported.

Certified POSIX conformance exists when conformance is certified by an accredited, independent certification authority. For example, LynxOS has been certified conformant to POSIX 1003.1-1996 by Mindcraft, Inc. and tested against FIPS 151-2 (Federal Information Processing Standard).

POSIX compliance is a less powerful label, and could merely mean that a product provides partial POSIX support. “POSIX compliance” means that documentation is available that shows which POSIX features are supported and which are not.

• Be wary of claims like POSIX operating system or 95% POSIX, which do not specify POSIX conformance.
• Remember that POSIX compliance does not always mean that all POSIX-defined features are supported.

ALWAYS ASK FOR PROOF OF POSIX CONFORMANCE

The IEEE stipulates that a conformance document must be made available for products which claim POSIX conformance.

The LynxOS real-time operating system is certified POSIX-conformant and also supports all of the routines in POSIX.1b and POSIX.1c. We subject LynxOS to our test suites for POSIX.1, POSIX.1b, and POSIX.1c. A failure from any POSIX call in our test suites is considered a bug and is kicked back to engineering for repair.

But is it POSIX-Conformant?