PXROS is an operating system for hard real-time. It was developed by HighTec and has been in successful operation for more than 20 years in different fields ranging from communications technology to the industrial sector and to safety-critical applications (SIL-4).

PXROS

A task-based operating system makes it easier to structure software since it modularises the components of the application. In this context, a task is an independent main-loop which is activated by the operating system via events or messages. The philosophy of PXROS supports strict encapsulation of parts of the application (tasks), allowing a simplified certification of the overall system. In doing so, standard components such as RAM/ROM tests and CPU tests for safety-critical applications have already been certified with SIL-4 as a so-called toolbox for PXROS. A designer is available within Eclipse for creating safety-critical applications via the toolbox.
PXROS is a multitasking operating system for hard real-time. PXROS manages several independent parts of the application, called tasks, which can be executed in a quasi-parallel way on the microcontroller. Task processing is controlled by assigning priorities and exchanging messages and events. This event-controlled method of operation renders hardware timers unnecessary. Events are used exclusively for signalling. They do not contain any data and thus do not tie up any resources.

PXROS meets hard real-time requirements

There are no global interrupt locks within the PXROS microkernel. PXROS tasks as well as the kernel can be interrupted at any time. Apart from this, PXROS does not cause any interrupt latencies. These two features guarantee a deterministic time behaviour and thus hard real-time. The computing power and resources available outside the interrupts are managed by PXROS and allocated to the tasks.

PXROS is a robust operating system

Within PXROS, an asynchronous communication takes place via events and message objects. This method supports the robustness of the system and keeps it free of reactions. The chronological execution of tasks is realised according to their priority.

PXROS is an object-oriented operating system

Communication between parts of the application (tasks) is realised in PXROS via events and messages. This means, for example, that a message object is used for transferring data between tasks. The object in question is requested from PXROS, filled with data, and sent to the recipient. Instead of the data being copied, there is merely a change of ownership to the data taking place. This procedure makes it possible to state the exact time span for sending the message even in the worst case.

PXROS is a safe operating system

The strict structuring and encapsulation of the applications (tasks) permits an allocation of resources which results in possible bottlenecks being restricted locally without affecting the overall system. Besides this, strict modularisation makes it easier to maintain and exchange parts of the application.

PXROS is portable

Applications can be compiled for any of the supported targets (TriCore, ARM, PowerPC, C16x, and x86) in full and without any changes. It is only the hardware-dependent parts that have to be adapted. Due to the separation made possible by the task concept, this adaptation can be realised by simply exchanging the relevant tasks.

Monitoring under PXROS

PXview

PXview is a graphic tool which helps developers analyse the communication between tasks, and the time behaviour within the system. In doing so, the scheduling of tasks, transfer of messages and events, and other services provided by the PXROS operating system are visualised.

PXmon

PXmon is a monitor which runs at the target of the application. The user can connect to the terminal and access vital information such as the status of a task and its usage of stack.

PXosci

PXosci visualises data measured within an application in a software oscilloscope

Communication with PXview, PXmon, and PXosci can be facilitated via a UART or TCP/IP interface.

PXROS is extendible

Available platforms:

• Windows Vista, XP, 2000
• Linux