Is WinCE a Hard Real-time Operating System?

April 22nd, 2013 by

By Andy The

There is a lot of debate whether WinCE is a hard real-time or soft real-time operating system.  The answer is yes and yes.

The reason why it can be yes in both cases is because it depends on your specific definition of hard real-time.

If your definition of hard real-time means that the interrupt jitter or latency has to be less and 10 microseconds, then WinCE is not a hard real-time OS under this definition.  If your hard real-time definition allows for 50-100 microseconds of jitter or latency, then WinCE can be considered a hard real-time OS.

Typically WinCE can have interrupt latencies that vary between 50-100 microseconds.  In some applications that require periodic interrupts in the millisecond range then this can be quite acceptable.  However, for applications that require periodic interrupts in the 1-100 microsecond range, WinCE will fail miserably under these circumstances.   The interrupt latency with WinCE is just too large and it will cause interrupts to be missed.

In the end, it will depend on the specific needs of the real-time system to determine if WinCE is a hard or soft real-time and if it will be a suitable OS for the application.

I should also mention that WinCE is not the only Windows based real-time operating system. Standard Windows and Windows Embedded can also be used as real-time operating systems  thanks to real-time 3rd party add-ons like IntervalZero’s RTX.


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