INT 27H: Terminate but Stay Resident

                                                         Compatibility: 1.0+ 
 Expects: DX    last addr+1 to keep resident
                (note: DX is an offset from the PSP segment)
 Returns: none  (not applicable)
    Info: This service terminates the caller, leaving a portion of memory
          allocated and resident in memory.  Subsequent programs will not
          overwrite the code or data left in memory.  See TSR for a list of
          related topics.

          INT 27H is the traditional method used to install interrupt
          service routines and user-definable data tables, but it is
          ◄superseded► by DOS Fn 31H (KEEP).  That fn provides a way to
          leave more than 64K resident and it allows you to set an exit
          code when you terminate.

          INT 27H (and all DOS exit services) restore the vectors for INTs
          22H-24H from the exiting program's PSP.  Therefore this service
          cannot be used to install a permanent Critical Error or
          Ctrl-Break handler.

See Also: fn 31H (terminate and stay resident)
          TSR/Popup Functions
          Program Startup & Exit
          DOS Functions
          DOS Interrupts