Storage Devices

Storage Devices

A storage device is a “hardware device designed to store information”. There are two types of storage devices used in computers; a ‘primary storage (internal)’ device and a “Secondary Storage (external)’ device.

Internal	External
(Primary Storage)	(Secondary Storage) Backing Storage
RAM	Hard Disk
ROM	Floppy Disk
Register	CD ROM
Cache	Magnetic Tape

Features of Internal & External Storage Devices

• Internal memories are faster than external memories.
• Internal memories directly communicate with the CPU. Where as External memories must communicate to the CPU through the internal memory.
• In general internal memories are temporary (except ROM) and External memories are permanent.
• Internal memories more expensive than external memories.

Primary & Secondary Storage Devices

Primary: “A storage location that holds memory for short periods or overwritten”. For computer RAM is an example of a primary (Volatile) storage device.

Secondary: “A storage medium that holds information until it is deleted or overwritten”. For example of a secondary storage device. (Nonvolatile)