... how to bypass Windows' "port protection", and they are often used for good purpose.

However, we started to breathe life into miniLA writing a rudimentary DOS utility, too; so we don't need to tackle with Windows' peculiarities right at the beginning. I have sent you that rudimentary utility's source privately - maybe it will provide some inspiration.

And, of course, the compulsory reading is that beyondlogic.org page somebody already suggested here.

JW