Also known as: storage, data storage
Storage is where a computer keeps data long-term, so that files and programs survive a power cycle.1 It is the permanent counterpart to RAM.
Overview
Storage comes in a few common forms:
- HDD (hard disk drive): data on spinning magnetic platters — cheap and high-capacity, but slower and mechanically fragile.
- SSD (solid-state drive): flash memory with no moving parts — faster, quieter, and more rugged.
- Flash memory: the non-volatile technology inside SSDs, SD cards, and the on-board storage of small devices.
All of these are non-volatile — they hold their contents with the power off, unlike RAM. The trade-off is speed: even fast storage is much slower than RAM, which is why the CPU does its active work in memory and reads from or writes to storage only when it must.
Where it fits
Storage is one of the four building blocks of computer hardware. On a single-board computer it is often a microSD card; on a microcontroller it may be a small block of on-chip flash; on a server it can be racks of SSDs.
Sources
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Computer data storage — Wikipedia, on non-volatile storage and HDD/SSD/flash technologies. ↩