UserPort.SYS is a kernel mode driver for Windows NT/2000 that gives usermode programs access to I/O Ports. This makes it possible to access hardware directly from a normal executable in the same way as under Windows 95/98/ME. This driver does not work on Windows 95/98/ME and there is really no need to run it anyway because I/O ports are always granted to usermode programs on these operating systems. The driver can be used for the following purposes: • To run software on Windows NT/2000 that normally only runs on Windows 95/98/ME. • To easily access hardware like the parallel port and other I/O ports. So what’s the drawbacks with this wonderful software? Microsoft has for security reasons prohibited usermode access to I/O ports. Opening up I/O ports creates a big security hole in your system. You should therefore carefully set the grant lists to only give usermode access to the specific I/O ports you need. The default values opens up a wide range of I/O ports and you should narrow it down. If you are writing your own software you should only grant access through the file “\\.\UserPort”. Access is then given to your program when you open the file “\\.\UserPort”. Other programs that don’t open “\\.\UserPort” will not have access to these I/O ports.
The driver can be installed in the following two ways: • Copy UserPort.SYS to %WINDIR%\SYSTEM32\DRIVERS Start UserPort.EXE and add the addresses you want and remove the others and click on start. • Run UserPort.EXE with the driver filename and path as an argument i.e. run UserPort.EXE X:\YOURDIR\UserPort.SYS Add the addresses you want and remove the others and click on start. You should now have usermode access to the addresses you have chosen.
Port instructions are not included in development environments (such as Visual C++ and Delphi) because direct I/O access isn’t allowed by the operating system. You will therefore need to include a portion of