>recently i had to reinstall a foxpro for dos application on NT4 from netware 3.12. many times the response is very slow comapred to that of netware.

Because many DOS programs are not well behaved, NT executes a DOS program in an isolated process and monitors what it is doing, checking for things like accessing hardware directly. NT wants to make sure the DOS program can't crash the system. The overhead involved in monitoring the program causes a DOS program to execute more slowly.