Product:    ISaGRAF 4.1x
Date: 23-April-2002
File: Why ISaVM on RTX does not block NT processes.htm
Subject: Why ISaGRAF Virtual Machine on RTX does not block the
NT processes even when there are cycle overflows
Keywords: RTX - process


Here is why the ISaGRAF V.M. releases the CPU and make it
available to Windows NT processes even if there are cycle overflows.

When in the V.M. there is a cycle overflow, there is still at
the end of the cycle a "dsystimewait" call.

If a program (= the V.M. when there is a cycle overflow) passes
0ms as parameter value when calling "dsystimewait" function, what
occurs is that:
calling program (=V.M.) still waits 1ms, so during that time the CPU
is available to the NT processes.
Among Windows NT processes there are the other ISaGRAF target
tasks that ensure communication, it is important they are not

So it is important that : The V.M. running on RTX does not block NT


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