Directed Random Test VS. Random Direct Test

Hi all guys,

I am confusing with the directed random test and random direct test. Could you give me a clear explain?
When to use directed random test, and when to use random direct test?

Thanks

Let me make a try to figure out your question.

I am not quite sure, but I think......

Directed random test is a randow test, but you may designate some design space
for tools to generate random test in it. So the random test is directed.

Random direct test is a direct test, means you are testing on a specific point/part of your design. But you use random tools trying to cover all the cases.

Let's say, you are testing MMU and only on some test pattern. It is a direct test, but you can use some tools to generate randomly the test codes.

And when you are trying to test a processor. You can use ISG to randomly generate the assmbler code as your test cases. That is a random test. But you may direct your tools to generate some codes you are interested in.

Does this answer your question?

Regards,
rprince006