SD Card

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SD Card

(Secure Digital Memory Card) A family of very popular flash memory cards used for storage in portable devices. Introduced in 1999 by Panasonic, Toshiba and SanDisk, the original, full-size SD Card is the most popular digital camera storage, and the smaller mini and micro versions are widely used in mobile devices. Cards come in various write speeds for video recording (for details, see SD Card classes).

Although SD Cards support encryption and content protection (the "Secure" in SD), they have been mostly used for regular storage. SD uses NAND flash technology (see flash memory).

Full-Size Card
With capacities available up to 1TB, the full-size SD Card is the original and largest in the series. It uses the same 32x24mm form factor but is slightly thicker than its MultiMediaCard predecessor (see MMC), and SD Card readers accept both formats.

Mini and Micro Sizes
Introduced in 2003 and 2005 respectively, the smaller miniSD and microSD formats are electrically and software compatible with the full-size SD. Using adapters, they plug into full-size slots (see illustration below). Subsequent SDHC and SDXC formats also came in mini and micro versions; however, all miniSD cards were nowhere near as popular as the microSD formats (see microSD).

SDHC (High Capacity) and SDXC (Extended Capacity)
In 2006, SDHC cards using the FAT32 file system superseded the original SD format, which used FAT16, and SDHC devices support SD. Introduced in 2009, SDXC cards raised the maximum capacity to 2TB by using the exFAT file system, and SDXC devices also support SDHC cards. See Video HD, Eye-Fi, gruvi card and SDIO card.

Ultra High Speed - UHS-I/II
In 2010, the UHS-I interface was introduced for SDHC and SDXC cards, dramatically increasing the bus speed for 4K video and continuous still recording. For more details, see SD Card classes.

Micro, Mini and Full-Size
The full-size SD Card (right) is approximately 1.25 inches tall by one inch wide. The "gruvi" is a copy protected microSD. (Image courtesy of SanDisk Corporation,

SD Card Adapter
Devices that use miniSDs and microSDs accept only those card types, but general-purpose SD readers have full-size slots and require adapters for the smaller cards.
References in periodicals archive ?
The camera records colour footage directly onto an SD memory card (not included), and will automatically switch to night recording mode.
UKPRwire, Fri Oct 02 2015] MagicRAM launches high capacity 512GB MLC SDXC UHS-1 card that is compliant with SD Memory Card Standard version 3.
com)-- According to a new market report published by Persistence Market Research "Global Market Study on Secure Digital (SD) Memory Card: Micro SD Card to be the Largest Segment by 2022," The Global SD Memory Card Market was valued at USD 7,705.
California-based memory card standards group The SD Association has announced an enhanced iSDIO specification offering a SD memory card with TransferJet contactless communications.
The cards are the first in the EXCERIA line-up to integrate a newly developed controller complaint with UHS-II the ultra high speed serial bus interface defined in SD memory Card Standard Ver.
The camera records colour footage directly onto an SD memory card (not included), and will detect low light levels and automatically switch to night recording mode.
Both companies' cards are compatible with a high-speed version of the widely used SD memory card standard.
Each device has a 4-GB SD memory card and is expandable to 32-GB SD memory for collecting up to 16 billion measurements.
With 32MB of built-in memory, plus an expandable SD memory card slot (up to a 4GB card), there's no shortage of storage capacity.
Toshiba will continue to expand and upgrade its SDHC and SD Memory Card series to meet the growing demand for high speed, high capacity products.
This XGA output portable document camera can store 2,048 images on one 256MB SD memory card, which can be archived when downloaded to a PC's hard drive or displayed as thumbnails for quick file searches.
The Audio player uses SD memory card slot instead of the HDD resulting in a compact, light and stable sound.