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, also known as peripheral 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 or core storage
   * Delay line memory
   * DVD-RAM
   * DVD-ROM
   * Flash memory
   * Floppy disk
   * Hard disk
   * Holographic memory
   * 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