RAM "filesystem"

Every QNX system also provides a simple RAM-based filesystem that allows read/write files to be placed under /dev/shmem.

Note that /dev/shmem isn't actually a filesystem. It's a window onto the shared memory names that happens to have some filesystem-like characteristics.

This RAM filesystem finds the most use in tiny embedded systems where persistent storage across reboots isn't required, yet where a small, fast, temporary-storage filesystem with limited features is called for.

The filesystem comes for free with procnto and doesn't require any setup. You can simply create files under /dev/shmem and grow them to any size (depending on RAM resources).

Although the RAM filesystem itself doesn't support hard or soft links or directories, you can create a link to it by using process-manager links. For example, you could create a link to a RAM-based /tmp directory:

ln -sP /dev/shmem /tmp

This tells procnto to create a process manager link to /dev/shmem known as /tmp. Application programs can then open files under /tmp as if it were a normal filesystem.

In order to minimize the size of the RAM filesystem code inside the process manager, this filesystem specifically doesn't include big filesystem features such as file locking and directory creation.