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

Index

Fatal error: Uncaught PDOException: SQLSTATE[HY000]: General error: 8 attempt to write a readonly database in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php:78 Stack trace: #0 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(78): PDOStatement->execute(Array) #1 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(30): insert_webrequest_('/notes/Linux/fh...', 1758206880, '216.73.216.150', 'Mozilla/5.0 App...', NULL) #2 /home/httpd/vhosts/renenyffenegger.ch/httpsdocs/notes/Linux/fhs/dev/shm/index(57): insert_webrequest() #3 {main} thrown in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php on line 78