What Are Secure Digital Memory Cards?
Secure digital (SD) memory cards are flash memory cards which meet the standards of the Secure Digital Association, a group of manufacturers which sets and certifies SD cards. Typically, secure digital memory cards can store between one and four gigabytes of data, and are designed for use in portable devices like cameras. They are what is known as nonvolatile memory cards, because they do not need to be connected to a power source to retain their stored data. The secure digital technology was introduced in 1999, and quickly became a widely-adopted standard for memory cards. Several manufacturers got together to establish the SD standard and to found the SD Association, recognizing the value of manufacturing flash memory cards to a common standard. Many of these manufacturers also produce devices which work with these cards.
