CPU Usage

When I run my program(write and read on ISA bus) with Windows NT, it appears that it takes 99% of the CPU usage. You will understand that it is not what I aim at.
Could you explain me why or/and what can I do to change this ?
I know that this post is general but perhaps you could put me on a right way.

Thanks a lot.

Philippe

If you are using a worker thread or a while loop this is normal.What you should do is to suspend the thead if you are finished and to resume the thread if there is a new read/write.