Secure Digital SD卡
（重定向自SDXC）
Secure Digital (SD) is a non-volatile memory card format developed by the SD Card Association (SDA) for use in portable devices.
The standard was introduced in August 1999 by joint efforts between SanDisk, Panasonic (Matsushita Electric) and Toshiba as an improvement over MultiMediaCards (MMC), and has become the industry standard. The three companies formed SD-3C, LLC, a company that licenses and enforces intellectual property rights associated with SD memory cards and SD host and ancillary products.