Scratch space is space on the hard disk drive that is dedicated for only temporary storage. It cannot be used to permanently backup

Backup

In information technology, a backup or the process of backing up is making copies of data which may be used to restore the original after a data loss event. The verb form is back up in two words, whereas the noun is backup....

 files. Scratch disks can be set to erase all data at regular intervals so that the disk space is left free for future use. The management of scratch disk space is typically dynamic, occurring when needed.

Scratch space is commonly used in graphic design

Graphic design

Graphic design is a creative process – most often involving a client and a designer and usually completed in conjunction with producers of form – undertaken in order to convey a specific message to a targeted audience...

 programs, such as Adobe Photoshop

Adobe Photoshop

Adobe Photoshop is a graphics editing program developed and published by Adobe Systems Incorporated.Adobe's 2003 "Creative Suite" rebranding led to Adobe Photoshop 8's renaming to Adobe Photoshop CS. Thus, Adobe Photoshop CS5 is the 12th major release of Adobe Photoshop...

. It is used when the program needs more memory, and the amount of available system RAM

Ram

-Animals:*Ram, an uncastrated male sheep*Ram cichlid, a species of freshwater fish endemic to Colombia and Venezuela-Military:*Battering ram*Ramming, a military tactic in which one vehicle runs into another...

 is insufficient. A common error in that program is "scratch disks full", which occurs when one has left the scratch disks configured to the default setting, being the boot drive. Many computer users gradually fill up their primary hard drive with permanent data, slowly reducing the amount of space the scratch disk may take up.

Partitioning off several gigabytes of hard drive and leaving that space empty will ensure a reliable scratch disk. Hard drive space, on a per-gigabyte basis, is far cheaper than RAM, though performs far slower. Even if on a separate physical drive (even a high-spindle drive such as a 'WD Raptor

WD Raptor

The Western Digital Raptor is a series of high performance hard disk drives produced by Western Digital. The drive currently occupies a niche in the enthusiast, workstation and small-server market...

' or an SSD

Solid-state drive

A solid-state drive , sometimes called a solid-state disk or electronic disk, is a data storage device that uses solid-state memory to store persistent data with the intention of providing access in the same manner of a traditional block i/o hard disk drive...

), to the main operating system and software, a scratch disk cannot match RAM for speed. However, since 10,000 RPM hard drives or SSDs can be purchased with capacities of up to 300 GB or beyond - whereas few motherboards can handle more than 32 GB of RAM - for applications such as video editing, it is a reasonable solution.

See also

• Scratch tape
  Scratch tape
  In data processing, a scratch tape is a magnetic tape that is used for temporary storage and can be reused or erased after the completion of a job or processing run. During the early years of computing, when magnetic tape was the primary form of mass storage, many programs, notably sorting...
  
  
• Swap partition
• Temporary folder
  Temporary folder
  In computing, a temporary folder or temporary directory is a directory used to hold temporary files. Many operating systems and some software automatically delete the contents of this directory at bootup or at regular intervals....
  
  
• TMPDIR
  TMPDIR
  TMPDIR is the canonical Unix environment variable that should be used to specify a temporary directory for scratch space. Most Unix programs will honor this setting and use its value to denote the scratch area for temporary files instead of the common default of /tmp or /var/tmp.Other forms...