nDevice
drivers (disks, tapes, adapters, etc)
nFile
systems (UFS/VxFS/JFS/NFS, etc)
nNetwork
interfaces (rsh pipes/NFS traffic).
nVirtual
Memory via memory mapped files.
nSerial
or parallel lines.
nPipes
(regular or named).
nMost any
device capable of supporting standard
open/read/write/close() API’s.
nExclude
non-essential features by removing:
ucompilation
flags: -DMMAP -DFIFO -DTTY