System V IPC
CONFIG_SYSVIPC
  Inter Process Communication is a suite of library functions and
  system calls which let processes (running programs) synchronize and
  exchange information. It is generally considered to be a good thing,
  and some programs won't run unless you say Y here. In particular, if
  you want to run the DOS emulator dosemu under Linux (read the
  DOSEMU-HOWTO, available from
  http://www.linuxdoc.org/docs.html#howto ), you'll need to say Y
  here.
 
  You can find documentation about IPC with "info ipc" and also in
  section 6.4 of the Linux Programmer's Guide, available from
  http://www.linuxdoc.org/docs.html#guide .
 
  Shared memory is now implemented using a new (minimal) virtual file
  system, which you need to mount before programs can use shared memory.
  To do this automatically at system startup just add the following line
  to your /etc/fstab:
 
  none  /var/shm        shm     defaults        0 0
 
  Saying Y here enlarges your kernel by about 18 KB. Just say Y.