tmpfs

tmpfs (short for temporary file system) is a temporary file storage paradigm implemented in many Unix-like operating systems. It is intended to appear as a mounted file system, but data is stored in volatile memory rather than on a persistent storage device.

The idea behind tmpfs is similar to that of a RAM disk, in that both provide a file system stored in volatile memory; however, the implementations differ. While tmpfs is implemented at the logical file system layer, a RAM disk is implemented at the physical file system layer. In other words, a RAM disk is a virtual block device with a normal file system running on top of it, while tmpfs is a virtual file system without any underlying block device.