Secondary storage

Secondary storage

Magnetic, optical and solid-state storage, plus cloud storage.

Transcript

Secondary storage keeps data when the power is off. Magnetic storage, a hard disk drive, has spinning platters. A read write head magnetises tiny patches, to store ones and zeros.

It is cheap for each gigabyte and has a large capacity, but it has moving parts, so it is slower, and a knock can damage it.

Optical storage uses a laser to read pits and lands on the surface of a spinning disc. A C D holds about seven hundred megabytes, a D V D about four point seven gigabytes, and a Blu ray disc about twenty five.

Solid state storage has no moving parts. Flash memory traps electrons in tiny cells, to store the bits. It is fast, silent, durable and uses little power, but costs more for each gigabyte.

Cloud storage keeps your data on servers owned by a company, reached over the internet. You can use it from any device, but you need a connection, and you rely on the provider for security.

Magnetic, optical, solid state, and the cloud. Each one trades speed, cost, and capacity.

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