Flash memory (computers)
Flash Memory is a reliable solid-state data storage medium. Unlike all other kinds of memory, flash chips hold an electrical charge using MOSFET's that have a special "floating gate". This is so well insulated that it can hold its charge, thereby controlling the transistor, almost indefinitely. The charge in the floating gate can be set using electrical impulses, and stored for long periods of time, even when power is disconnected.
This type of non-volatile memory comes with its own set of problems, but removes the need for constantly moving parts. However, the gates do eventually wear out with use; this systemic problem can only be slowed by wear-leveling algorithms (which all flash memory now uses) to distribute the wear evenly. Because of these factors, flash memory can fit in small, abnormal spaces, and tends to last longer in minimal-load applications. However, the hardware does wear out with use, and the charge also decays over time, so while data can typically be stored for a number of years, it will be eventually lost (due to bit rot) if it is not rewritten occasionally.
Common Uses
- Solid-state drives (computer drives)
- "Thumb Drives" (Flash memory drives)
- Compact Flash (CF) cards (for cameras)
- Secure Digital (SD) cards (for cameras, cellular phones, media players, etc.)
Notes
- Flash memory is taking over the digital storage market because of its convenience, durability, and size.
- Because of the wear-leveling algorithms used to extend the life of flash memory, certain, secure deletion (shredding) of digital files on flash memory is nearly impossible.[1]
- Conversely, flash memory is much more independently active than traditional disk drives, as it reallocates space and cleans old deleted data. This makes recovery of deleted data difficult, which can be both good and bad.[2][3]
