Creatfil.exe - Windows 2003 Resource Kit Utility

This command-line tool creates an artificial file of any size. This is useful for testing the behavior of tools, applications, and setup programs under conditions of low available memory on a hard disk. Create File must be run from the command prompt; it cannot be run from the Run command on the Start menu.
Switches:
Path - Specifies the directory where the file will be created.
FileName - Specifies the name of the file that will be created.
FileSize - Specifies the size of the file in 1KB increments.