Entry:
          AX = 5D01h
          DS:DX -> buffer (see AX=5D0Ah), only fields at offset 12h, 14h used
          ???

        Return:
           ???
        Note: Does something to each disk file in the System File Table which
              has been  written to; if remote file, calls INT 2F/AX=1107h
              seems to update the time stamp of all open files which have