Re: Query re: disk free (df) output

[Jhair Tocancipa Triana <jhair.tocancipa@gmail.com>]

andy  writes:

> I suppose I could've been more specific: what might a "shm" be?

,----[ /usr/src/linux/Documentation/devices.txt ]
| The following names are reserved for mounting special filesystems
| under /dev.  These special filesystems provide kernel interfaces that
| cannot be provided with standard device nodes.
| 
| /dev/shm        tmpfs           POSIX shared memory maintenance access
`----

The linux kernel implements shared memory with the help of a minimal
filesystem which is mounted in /dev/shm.

More information about POSIX shared memory can be found in the
relevant man pages,

,----[ apropos shm ]
| shm_open (3)         - Create/open or unlink POSIX shared memory objects
| shm_unlink (3)       - Create/open or unlink POSIX shared memory objects
| shmat (2)            - shared memory operations
| shmctl (2)           - shared memory control
| shmdt (2)            - shared memory operations
| shmget (2)           - allocates a shared memory segment
| shmop (2)            - shared memory operations
`----

-- 
-- Jhair