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Re: /dev/shm ?

On Fri, Apr 05, 2002 at 03:32:30PM -0600, Erich Schroeder wrote:
> What is /dev/shm? It showed up after an apt-get upgrade to RH 7.2.

It's a new thing in 2.4.x.  From Documentation/filesystems/tmpfs:

 2) glibc 2.2 and above expects tmpfs to be mounted at /dev/shm for
    POSIX shared memory (shm_open, shm_unlink). Adding the following
    line to /etc/fstab should take care of this:

         tmpfs   /dev/shm        tmpfs   defaults        0 0

    Remember to create the directory that you intend to mount tmpfs on
    if necessary (/dev/shm is automagically created if you use devfs).

    This mount is _not_ needed for SYSV shared memory. The internal
    mount is used for that. (In the 2.3 kernel versions it was
    necessary to mount the predecessor of tmpfs (shm fs) to use SYSV
    shared memory)

Red Hat adds the appropriate fstab entry for you (although they use
"none" for the first field, which I think is a bit more correct).

steve@silug.org           | Southern Illinois Linux Users Group
(618)398-7360             | See web site for meeting details.
Steven Pritchard          | http://www.silug.org/

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