Prex Embedded Real-time OS / News: Recent posts

This release adds new security framework which supports pathname-based access control. Now, we can assign the set of specific capabilities for any applications depending on its role.

This version includes FAT file system support. Unix pipe support and various bug corrections are also included.

This version includes POSIX emulation support. Some system servers and libraries are implemented. Various bug corrections are also included.

Initial release of the file system server.

This version includes some important kernel enhancement like DPC framework.

This is a maintenance release fixing a number of bugs.

This release includes ELF task relocation on NOMMU system. Some minor bugfixes were also added.

This is the first release to support security feature in kernel. The concept named "task capability" is added to improve security function.

This release includes minor bugfixes and some feature enhancements. It adds kernel support for MUTEX_INITIALIZER to allow static initialization of mutex. A bug of object_lookup() syscall was fixed.

The source structure was improved with this release. The kernel APIs for synchronize objects (mutex, CV and semaphore) was updated for POSIX compatilbility. The driver ioctl code was changed to BSD style. It includes some other kernel bug fixes.

This release includes minor bugfixes and documentation update.

This release added Game Boy Advance port. It also contains the device driver for the on-screen keyboad.

This is a milestone release to support "NOMMU" microcontrollers. The new VM stub for NOMMU was added to keep the API compatibility with the MMU kernel. Now, an application can work on the MMU and NOMMU platforms without changing its source code.

Dynamic Voltage Scaling (DVS) with Pentium M processor has been supported in this release. It reduces the CPU power consumption without significant performance degradation. The voltage monitoring tool and the DVS demonstration program have been added.
The default power policy was changed to "Power Save Mode". If you want to optimize the system for the real-time performance, please change the power policy to the "Performance Mode". In this mode, DVS does not work and CPU will always run in highest speed.

Some major bug fixes and minor feature enhancements have been made in this release. It includes the fix for the timer overflow issue after 49.7 days of continous operation, and fix for the unexpected page fault in an exception handler. And, initial version of kernel monitor and some test programs were added. Kernel was improved to verify the page access for I/O buffer automatically. Newlib is required to build user mode applications with this release.

Prex is a portable real-time operating system for embedded systems. The small, reliable and low power micro kernel is designed specifically for the small memory footprint system.

Prex 0.1 is the first public release of Prex. It includes kernel, syscall library, sample hello world application, and some technical documents. Almost kernel features (task, thread, ipc, exception, timer, synch) have been implemented in this version, but they are not fully tested yet. Current Prex supports only i386-pc system as a Prex reference platform.... read more