RAM disk
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A RAM disk, ramdisk or RAMdrive is a segment of active computer memory, RAM, which is being used as secondary storage, typically a role for a disk drive. Access times are greatly improved, because RAM disks are approximately a thousand times faster than hard disk drives. However, durability of data through power loss is completely absent, because they are made of normal volatile RAM. As a result, RAM disks lose their contents once the computer is turned off. RAM disks are great places to store temporary data or to hold uncompressed programs for short periods.
A proper disk cache in the operating system will usually obviate the performance motivation for a RAM disk; a disk cache fulfills a similar role (fast access to data that is notionally stored on a disk) without the various penalties (data loss in the event of power loss, static partitioning, etc.). RAM disks are, however, indispensable in situations in which a physical disk is not available, or where access to, or changing a physical disk is not desirable (such as in the case of LiveCDs). They can also be used in a kiosk-style device where any changes made to a system are not committed and the original configuration is to be loaded each time the computer is turned on.
Another way to use RAM to store files is the temporary filesystem. The difference between temporary filesystem and a RAM disk is that the RAM disk (/dev/ram0 etc.) is fixed-sized and acts like a disk partition, whereas the temporary filesystem (/dev/shm; in Source Mage GNU/Linux also /tmp) grows and shrinks to fit the files put on it.
See Also
- ToRAM
- Cenatek - ramdisk creation program for Windows
- RAMDisk (http://www.ramdisk.tk) - free and paid Windows versions
External links
- LinuxFocus (http://www.linuxfocus.org/English/November1999/article124.html)