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Definition: storage


The permanent holding place for digital data until intentionally erased. Storage is a repository that retains its content without power and includes magnetic disks, solid state drives (SSDs) and USB drives. These storage devices are all "non-volatile." Rewritable CD, DVD and Blu-ray discs, as well as magnetic tapes, are also non-volatile storage.

Storage Is Not Main Memory
Storage specifically excludes the computer's main memory, comprising mostly dynamic RAM (DRAM) chips and a lesser amount of static RAM (SRAM) chips. Main memory is a temporary workspace for executing instructions and processing data, not retaining data permanently. Memory chips are "volatile. They lose their content when the power is turned off." See memory, dynamic RAM and static RAM.

Storage vs. Memory - More Confusing All the Time
Over the years, some vendors have referred to disks and tapes as "memory" products, which blurs the distinction between storage and memory (RAM). To confuse things even further, the chips in solid state drives (SSDs) and USB drives are "flash memory" chips. However, they are not volatile RAM chips; they are storage chips that hold their content without power. See storage vs. memory, magnetic disk, magnetic tape and optical disc.




They're All Chips, But...
The RAM chips (top) and the storage chips (bottom) in a USB drive and CompactFlash card (cases removed) may look alike, but RAM chips are fast and volatile, while storage chips are slower and non-volatile. See memory module, USB drive and CompactFlash.






Storage Evolution
In the early 1990s, this 670MB multi-platter hard drive weighed 17 pounds including its case. By 2006, a half-ounce Microdrive (center) had 12 times as much storage on a single platter the size of a quarter. The solid state microSD card (right) weighs half a gram. See hard disk and Microdrive.








Thirty Years of Progress
If 90 hard drive cabinets like this one from 1992 were lined up side-by-side, they would extend more than half a football field. Today, this microSD card (top) can hold the same amount of data. See microSD. (Image courtesy of The Computer History Museum.)