GT_CHDIR()       Change the current directory.
 GT_CLUSFRE()     Get the number of free clusters on a drive.
 GT_CLUSTER()     Get the number of clusters on a drive.
 GT_CURDRIVE()    Retreive The Current Drive Letter
 GT_DISKSIZE()    Return the size of a disk in bytes.
 GT_FILESPACE()   Calculate the ``real'' size of a file.
 GT_FLOPCNT()     Return a count of the floppy drives on a system.
 GT_FLOPNAM()     Get the name of the floppy drive on a single floppy system.
 GT_HARDCNT()     Return a count of the hard drives on a system.
 GT_MKDIR()       Make a new directory.
 GT_RMDIR()       Remove a directory.
 GT_SECPCLU()     Get the number of sectors per cluster on a drive.
 GT_SECTSIZ()     Get the size of a sector on a drive.