memorycard

A memory card, or memorycard, is a small, removable non-volatile storage device based on flash memory used to store digital data in portable devices. It enables expandable storage in cameras, smartphones, tablets, gaming consoles, drones, and embedded systems. It replaces built-in storage in many devices and allows data transfer via card readers or built-in slots.

Common formats include Secure Digital (SD) cards and their microSD variants, including SDHC and SDXC, which differ in capacity and filesystem; other formats such as CompactFlash (CF), Memory Stick, and xD-Picture Card were historically common but have diminished usage. SD cards are the most widely used today; microSD cards are used in small devices.

Capacity ranges from a few megabytes in early devices to current consumer cards up to 1–2 terabytes for microSD and SD cards, with professional cards marketed at higher performance. Performance is indicated by speed classes: Class 2–Class 10, UHS Speed Class (U1, U3), and Video Speed Class (V30, V60, V90). Some cards support higher read/write speeds and advanced controllers for wear leveling and error correction.

Filesystems: smaller SD cards (up to 32 GB) commonly formatted as FAT16/32; larger cards typically use exFAT. Cards include wear-leveling and bad-block management; write protection switch on SD cards provides a hardware lock in some models.

Handling: do not remove cards during active write operations, back up important data, keep away from extreme temperatures and moisture. Data recovery can be difficult if damaged; frequent backups are recommended.