SD card

An SD card is a removable flash-memory card standardized by the Secure Digital Association. It stores digital data and is widely used in cameras, computers, and other portable devices.

Flash memory: Nonvolatile semiconductor memory that stores data in electrically programmable cells. SD cards retain data without power using flash-memory chips.
NAND flash: A flash-memory technology that stores data in arrays of charge-trapping cells. Most SD-card storage is implemented with NAND flash.
Digital photography: Photography in which images are captured and stored as digital data. Cameras commonly use SD cards for image storage and transfer.
CompactFlash: A removable flash-memory card format introduced by SanDisk in 1994. It is an older, physically larger alternative used in some cameras.
Secure Digital: A family of standards governing removable memory cards, their interfaces, and related features. The SD card follows this broader standard family.
Flash memory controller: A processor that manages flash storage, including data placement, error correction, and wear. The card controller translates host commands into reliable flash operations.
Digital video: The representation and recording of moving images as digital data. High-bitrate video recording requires cards with adequate sustained write speeds.
Memory Stick: A family of removable memory-card formats developed by Sony. It was a proprietary alternative to SD cards in Sony devices.
SD Association: An industry organization that develops and maintains Secure Digital standards. It defines card formats, capacities, and interface specifications.
Wear leveling: A technique that distributes writes across flash-memory cells to reduce uneven wear. It helps extend the usable life of the card's flash cells.

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