BIOSRev()

         Returns the BIOS revision

    Syntax:

         BIOSRev() -> nRevision

    Description:

         Returns a number between 0 and 255, that is to say, the decimal
         value of a byte indicating the revision of the system's BIOS.
         The revision usually is in relation with the date of the BIOS.

    Return:

         A numeric value indicating the BIOS revision.

    Example:

         BIOSRev()