Computer storage

The terms storage or memory refer to those parts of a computer that retain data for some period of time, possibly even after the computer is turned off. There are many ways in which types of storage can be categorised - these include:

• Primary / Secondary
• Volatile / Non-volatile.
• Read-only[?] / WORM / Read-write[?]
• By medium - eg, Semiconductor[?] / Optical[?] / Magneto-optical[?] / Magnetic[?]

Normally, "memory" refers to primary, semiconductor based storage, but this is a very blurred distinction.

Each type of storage is suited for different purposes, and most computers contain several types.

Primary storage contains data that is actively being used (for example, the programs currently being run and the data they are operating on). It is typically high-speed, relatively small, and is often (but not always) volatile. It is sometimes referred to as "Main Memory".

Secondary storage is where the computer stores information that is not necessarily in current use. It is typically slower and has larger capacity than primary storage. It is almost always non-volatile.

Volatile storage loses its contents when it loses power. Non-volatile storage does not.

List of storage devices

• CD-R
• CD-ROM
• CD-RW
• Core memory
• Delay line memory
• DVD-RAM
• DVD-ROM
• Flash memory
• Floppy disk
• Hard disk
• Magnetic tape
• Magnetic drum
• Magneto Optical[?]
• Memory stick
• Mylar tape[?]
• NVRAM
• Punch card
• Paper tape
• RAM
• ROM
• Selectron tube
• Smartdisk[?]
• Thin film magnetic memory
• VRAM
• Williams tube
• WRAM[?]

Memory related software

• Aard
• QEMM[?]

See also

• Write protection