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Secondary storage
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Primary storage
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It is not directly accessed by the cpu
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It is directly accessed by the cpu
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Data is non volatile
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Data is volatile when cpu off
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Less expensive
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More expensive
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In some uses, primary storage and secondary storage refers to what was historically called secondary and tertiary storage respectively. Tertiary storage or tertiary memory is a system where a robotic arm will mount (insert) and dismount removable mass storage media into a storage area according to the system demands. It is useful for extraordinarily large data stores, accessed without human operators. This is rarely accessed information since it is much slower than secondary storage. Examples include tape libraries and optical juke boxes.
