Int 7F Fn 05  - Alloy Ntnx (host) - Lock/unlock System, Spooler Control    [N]

   AH = 05h
   AL = function
       00h lock system (disable slave services)
       01h unlock system
       02h enable spooler
       03h disable spooler
       04h enable slave timer update
       05h disable slave timer update
       06h enable form feeds
       07h disable form feeds

See Also: INT 17/AH=A4h