Disable OS Function Set Functions                       
  
    | 
       Input  | 
    
       Output  | 
   
  
    | 
       AX  | 
    5Dh | 
    01h | 
    Error
      Code | 
      | 
    AX | 
   
  
    | 
       BX  | 
      | 
      | 
    Access
      Key (1st invocation only) | 
    BX | 
   
  
    | 
       CX  | 
      | 
      | 
    Access
      Key (1st invocation only) | 
    CX | 
   
  
    | 
       DX  | 
      | 
      | 
      | 
      | 
    DX | 
   
      Lets the OS allow other programs or device drivers to use  the OS
     specific functions. This capability  is  provided  only for an OS
     which manages regions of mappable conventional memory  and cannot
     permit programs to use  any  of  the  functions which affect that
     memory, but must be able to use these functions itself.
     Notes:
     *  This  function is for use by  operating  systems  only.  The
        operating system can disable this function at any time.
     *  The  OS/E  (Operating   System/Environment)  functions  this
        subfunctions affect are:
               Function 26. Get Expanded Memory Hardware Information.
               Function 28. Alternate Map Register Sets.
               Function 30. Enable/Disable Operating System Functions.  |