| A flash memory storage device usually is a solid-state re-recordable material deployed in a very small form factor, requiring absolutely no power to hold data. A micro SD memory stick is a shorter version of the original Secure Digital (SD) flash memory stick. Based on SanDisk’s TransFlash or T-Flash secure digital memory format, the format is a popular choice for memory card interfaces among cell phone manufacturing companies. The format allows for smaller physical sizes, providing larger storage capacities, along with a digital copyright protection feature known as Digital Rights Management.
The SD memory interface is developed from the MultiMediaCard (MMC) format with faster data transfer rates and thick casings. The data transfer rates are derived from the CD-Rom data transfer measurements, in multiples of 150 kb/s. Cheaper varieties of SD memory cards offer up to 6x or 900 kb/s of transfer rates. High-end or high-quality SD memory sticks are now supporting data transfer rates of up to 133x. The industry adopted norm is a speed of 66x or 10mb/s, significantly higher than the family of flash memory interfaces. The transfer rates have been defined in December 2005 to offer 66x of transfer rates by an SD memory card of version 1.01 specification and a transfer rate of 133x by a card with version 1.1 specification.
The SD interface usually measures 15 mm x 11 mm x 1 mm, one-fourth the size of the original Secure Digital memory card, making it the smallest memory card in the market. The format was introduced on March 14, 2005, at CTIA Wireless 2005 expo and the final specifications were released on July 13, 2005. Motorola launched the first cell phone featuring the MicroSD memory interface followed by Garmin, with their latest line of GPS receivers sporting the interface for storing downloaded maps and guides. The MicroSD memory stick is popular among digital cameras, handheld and laptop computers, telephones, music players, video game consoles, and other electronics devices for storing small amounts of data. MicroSD cards of capacities ranging between 128MB to 1GB (1024MB) in multiples of 128MB are available as of date. The interface has no limitation with respect to the maximum supported memory capacity. |
