INT 21 - Novell NetWare - WORKSTATION - GET DRIVE FLAG TABLE
        AX = EF01h
Return: ES:SI -> network shell's 32-byte drive flag table (see below)
Notes:  this function is supported by Advanced NetWare 1.0+
        each byte in the drive flag table corresponds to a drive
SeeAlso: AX=EF02h,AX=EF03h

Values in drive flag table:
 00h    drive is not mapped
 01h    permanent network drive
 02h    temporary network drive
 80h    mapped to local drive
 81h    local drive used as permanent network drive
 82h    local drive used as temporary network drive