How Does an SD Card Work?
A memory card is a flash memory storage device that holds your digital information. They were designed to be used for portable devices like digital cameras, mobile phones, laptops, tablets, and in some cases video game consoles. A memory card is a solid state device which means it has no moving parts, unlike a hard drive. The process of saving photos, videos, and other files to an SD card is electronic instead of mechanical.
Each card has flash memory, which contains grids and columns that have a transistor known as a floating gate and one known as the control gate. A floating gate can only gain access to a row of data if the control gate allows it. These microcontrollers communicate with the card and bring data to the flash storage known as NAND. When data is not being stored or overwritten, no power is needed, making SD cards the most power-efficient device. In addition to its power-saving modes, the design without moving parts makes it better protected from damage or wear and tear.
Humble Beginnings of the Memory Card
“Flash Memory” was invented by Fujio Masuoka. It was aptly named due to its high speed ability to erase contents, much like the flash of a camera. Though the flash memory concept came about in the early 80s, the first commercial memory card format, PC Cards, didn’t appear until 1990.
- The PC Card—Designed for computer storage on laptops. It was published by the Personal Computer Memory Card International Association. It had three types, all differing in thickness. It was offered in 16 bit or 32 bit.
- CompactFlash (CF)—Created by SanDisk in 1994. The CF is physically larger than other formats and originally used NOR flash memory, which could execute programs straight from flash without the need to copy to a device’s random access memory (RAM). It has a capacity of up to 512 GB and is typically used in mass storage devices like digital cameras.
- SmartMedia Cards—These cards were launched by Toshiba in 1995 and were designed to be a successor of the floppy disk. It was the thinnest of the early card models at .76mm and consisted of a single NAND flash chip in plastic casing. They are no longer in use due to their low storage capacity of 128 MB.
- Memory Stick—Sony launched the Memory Stick in 1998 with sizes up to 128 MB. They are only compatible with Sony products and are used with digital cameras and camcorders and comes in varying thickness. They can support transfer rates of up to 80 MB per second.
- Secure Digital (SD) Cards—The SD Card Association came out with the original SD card in 1999. It came as a collaborative effort between SanDisk, Panasonic and Toshiba. At its maximum, it could only hold 2GB. It was created to keep up with other types of storage media and was derived from the MultiMediaCard.
After the initial SD Card, several different types emerged including the miniSD, microSD, and SD High Capacity (HC). As the varieties progressed, they offered faster read and write speeds and the HC model had storage capacity of up to 32 GB.
The Future Is Here
SanDisk recently announced their new MicroSD Express line which has storage capacity of up to 1TB. It is available in microSDHC, microSDXC and microSDUC formats. It can be used in multiple media devices such as smartphones, cameras, and other portable electronics. Its read speed is 160 MB per second and the write speeds are 90 MB per second. With increased capacity, the card is the go-to choice for high-quality photo and video creators who have files that take up more room than a device’s RAM can handle. These new cards will be available for purchase in April of this year.
SD Cards Aren’t Invincible
Though the general design of a memory card makes it resilient to physical damage, it doesn’t ensure complete protection. Secure Data Recovery engineers have decades of experience retrieving data from flash memory cards. Whether it’s physical damage, logical damage, or an accidental overwrite, we can recover your photos and files. For more information on our SD recovery, call our customer service line at 800-388-1266.