NAME

     mem, kmem, port - system memory, kernel  memory  and  system
     ports


DESCRIPTION

     Mem is a character device file that is an image of the  main
     memory  of  the  computer.   It may be used, for example, to
     examine (and even patch) the system.

     Byte addresses in mem are  interpreted  as  physical  memory
     addresses.    References  to  non-existent  locations  cause
     errors to be returned.

     Examining and patching  is  likely  to  lead  to  unexpected
     results when read-only or write-only bits are present.

     It is typically created by:

          mknod -m 660 /dev/mem c 1 1
          chown root.mem /dev/mem


     The file kmem is the same as mem,  except  that  the  kernel
     virtual memory rather than physical memory is accessed.

     It is typically created by:

          mknod -m 640 /dev/kmem c 1 2
          chown root.mem /dev/kmem


     Port is similar to mem, but the IO ports are accessed.

     It is typically created by:

          mknod -m 660 /dev/port c 1 4
          chown root.mem /dev/port



FILES

     /dev/mem
     /dev/kmem
     /dev/port


SEE ALSO

     mknod(1), chown(1), ioperm(2)