The POSIX (Portable Operating System Interface) guest operating system resides in the mid-range of SYSGO's Safety product portfolio. It is primarily not designed for higher certification levels. However due to its small size and low memory footprint it is a safe and secure alternative to the Linux operating system in situations where massive feature support from the OS is needed.


The POSIX guest OS implements a subset of the PSE52 profile of IEEE Std 1003.13-2003. Some additional real-time extensions and extensions for PikeOS are also included. These include specific ARINC 653 topics, such as sampling and queuing ports as well as PikeOS monitoring with POSIX awareness and PikeOS tracing support.

The POSIX OS, such as any other partition type, strictly underlies the PikeOS resource- and time-partition management. That includes processor core affinities, time partition slices as well as PikeOS system thread priority scheduling. However, the POSIX kernel implements its own scheduler which maps its user threads onto one PikeOS system thread. To be more precise, there is one PikeOS system thread per processor core available to a POSIX kernel. In addition, most of the POSIX drivers that provide asynchronous behaviour create their own I/O thread for enhanced I/O scheduling.

Certifiable File System (CFS)

The POSIX file system gives access to files located in the PikeOS file system, but also allows to open all available PikeOS volume providers and system drivers. In particular, SYSGO's certifiable file system (CFS) is fully supported.

Certifiable IP Stack (CIP)

With regards to connectivity, POSIX provides a whole range of buses and networks starting with serial communication, CAN interfaces and raw Ethernet access. On top of that, two network stacks are available. The first one is based on LwIP and supports UDP as well TCP/IP connections. The second one is SYSGO's own implementation for Safety purposes: The certifiable IP stack.

The POSIX kernel is shipped as a linkable library allowing user applications to be directly linked against it. The process is integrated into the CODEO IDE which automatically handles all toolchain related settings. No need to hassle with paths to include or library files.

The number of parallel POSIX instances is only confined by PikeOS systems limits as a POSIX partition fits into a PikeOS system like any partition type.

Apart from the obvious use cases, such as AUTOSAR adaptive, Industrial Automation and Medical there are no limits to usage of the POSIX guest operating system.

POSIX for PikeOS supports both the C and C++environment.

Customer Benefits


POSIX standard API allows migration of existing software


Robust and small implementation provides solid base for application development


Feature-rich API for usage in projects with mixed criticality


Socket API for LwIP and CIP provides network access in standard manner


Small code base results in little attack surface increasing overall Security


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