Ramdisks

A ramdisk, short for RAM disk, is a block device created in volatile random-access memory that presents itself to the operating system as a disk drive. Because it uses system RAM, all data stored on a ramdisk is typically lost when power is removed or the system reboots unless an external mechanism saves and reloads it. Ramdisks offer extremely high input/output speeds and low latency compared to traditional disks, making them well suited for temporary data, caches, and workloads with intense I/O requirements.

Implementation and availability vary by operating system. Linux provides memory-backed file systems such as ramfs and tmpfs, which can be mounted to behave like disks or used as fast temporary storage. Some Linux configurations can also create dedicated memory-backed block devices via kernel modules. Windows and macOS likewise support ramdisk functionality through built-in features or third-party software, such as tools that allocate a portion of RAM as a drive or that create a memory-backed disk image.

Common use cases include storing build caches, browser profiles, and temporary workspace for compilers or data processing tasks, where frequent, fast reads and writes reduce overall processing time. Ramdisks are also used for database temporary tables, media rendering scratch space, and test environments where reproducible, fast I/O is desirable.

Key considerations when using a ramdisk include limited available RAM, potential system memory pressure, and the risk of data loss on power failure. A ramdisk is best treated as volatile scratch space; important data should be kept on persistent storage and backed up. Some users implement periodic persistence by saving the ramdisk contents to disk at intervals or on shutdown.