21.4 REAL-TIME PROCESSING

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Any computer running a process should use a real-time operating system. The purpose of a real-time operating system is primarily to ensure that a process runs within a specified time interval, normally a small fraction of a system. This capability is often not a common part of most operating systems, but it is relatively easy to add. When it is not a real-time process, it common for another process to monopolize the processor and cause erratic delays. When this happens the control program may not respond to a control event for a second or more. This would generally be a bad thing in a time critical system.

- need to be able to specify how often a process runs.

- RTLinux

- system clock for slower processes.