SD card is made by Toshiba adding encryption technology to MMC card technology. Because MMC cards may make it easier for users to copy digital music, Toshiba added these technologies, hoping to reassure the music industry. Similar technology is Sony's MagicGate. Theoretically, encryption technology can introduce some digital rights management measures, but this function is rarely used.
Users can use USB card reader and SD card on personal computer. Some new computers have built-in card reading devices.
The "SD" trademark is actually used for another completely different purpose: it was first used on the "ultra-density optical disc", which was developed by Toshiba and lost the battle for DVD format. That's why the word "D" looks like a CD.
SD series memory cards will be sent to SD card association for certification after SanDisk completes the test, so almost all patents are in SanDisk's hands. But in 2007, SanDisk sold his possessions because of the turmoil in the NAND market, giving the outside world an illusion that it is about to disappear. I lost many of my core technologies and patents, and the most important NAND factories were sold to Micron. Not long after, Sandisk, which has re-attracted foreign investment and changed its face, has no intention of developing flash memory technology and establishing a new factory. Instead, we invest in Toshiba, cooperate with Toshiba, and use Toshiba's manufacturing technology and technology to produce chips. After that, Toshiba's new products will have two brands of LOGO. SD card is no exception. There are many similarities between the products of the two brands, which are also the main sources of SD card market.