A secure digital card (SD card) is a small flash memory device designed to provide high-capacity memory in a portable size. A standard SD card measures 32mm x 24mm x 2.1mm and weighs approximately 2 grams, whereas miniSD and microSD cards are physically much smaller but contain a similar capacity of memory.
Variations of SD cards include Secure Digital High Capacity (SDHC), Secure Digital eXtended Capacity (SDXC), and Secure Digital Ultra Capacity (SDUC). These types of SD cards were designed to offer dramatically more capacity than a standard SD card.
To access data written on an SD card, users typically need a USB card reader. Once the card is inserted in the card reader and the card reader is connected to a computer, users can access and modify the files as they would with any other flash memory device. It’s important to note that SD cards are meant for temporary use; in fact, the data stored on an SD card has a maximum shelf life of 10 years.
History of the SD card
The first SD card was developed collaboratively by SanDisk, Matsushita, and Toshiba in 1999. It was intended to be a more compact alternative to Sony’s Memory Stick. The first SD cards could hold up to 2 GB of data.
The rise of mobile phones shortly after the initial SD card launch revealed that the standard SD card was becoming too large for most mobile phones, and the miniSD card was created in 2003 as a result. Two years later, an even smaller SD card was launched with the microSD card, again for the purpose of meeting the demands of mobile device manufacturers.
In the decade that followed, new SD card variations were released every few years to offer more capacity than its predecessor. SDHC and miniSDHC cards can store up to 32 GB of data, the SDXC cards can store up to 2 terabytes (TB) of data, and the massive SDUC cards support up to 128 tebibytes (TiB). For reference, one terabyte is the equivalent of 1000 gigabytes, and one tebibyte is equivalent to 1099.51 gigabytes.
SD card uses
Because of their compact size, SD cards are used to store and transfer files in a number of different devices, including:
- Mobile phones and smartphones
- Digital cameras
- Video camcorders
- Gaming consoles
- Newer TV models
- MP3 audio players
