Search notes:

/dev/shm

/dev/shm can be used to share data between processes.
This directory is also (or only?) the place where named semaphores are created.
Apparently, on some systems, /dev/shm is a symbolic link to /run/shm.

Oracle AMM

Oracle creates /dev/shm segments when automatic memory management is enabled: 
ls -l /dev/shm | grep $ORACLE_SID

See also

The Docker commands docker create and docker run have the option --shm-size to set the size of /dev/shm.
/proc/sysvipc/shm
/run/shm
/dev

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