REALTIME

Defining soft and hard realtime:

In a hard real-time system, an event is guaranteed to be handled within a certain time interval.
In a soft real-time system, an event on average is handled within a certain time interval.

Survey show that request for real-time solutions result in:

All embedded applications having a performance requirement
30 - 40 % have some realtime need
< 10 % require a hard realtime solution

More then 90 % of these requests for a realtime solution can be done with Linux as operating system. Kernel version 2.5 has a worst-case latency of 15 msecs which is very good for a soft realtime operating system.

When hard realtime solutions are required either RTLinux or a specific application can be used. With proper hardware, latencies shorter then 2 usecs can be obtained.

Linux can cope with both hard and soft real-time requirements by providing either a standard or a tailor-made solution. If you are interested in discussing this further you can send an e-mail to jan@ardistech.com