Useful Notes / SD Card

The winner of a relatively low-key format war, the Secure Digital Card, or SD Card, is a removable flash memory device meant to hold data from consumer electronics. Most notably digital cameras and recorders, cell phones, and gaming systems like the Nintendo Wii and Nintendo 3DS.

During the mid 90s with portable devices needing storage starting to emerge, SanDisk created the Compact Flash format flash device. Being a flat card of about 38mm x 25mm x 3mm, it was quickly met with other competition from Intel, Toshiba, and Sony. By the late 90s, SanDisk had created another format, the Multimedia Card, to compete with the other offerings as Compact Flash wasn't as compact as the other formats; by then memory cards were about the size of a postage stamp and less than 2mm thick. Multimedia Card ultimately won out because of its open standard, while everyone else was using proprietary formats. It was also very easy to interface to, which was very useful in small electronic devices. The only standard to stubbornly stick to the end was Sony's MemoryStick, which strangely enough was co-developed with SanDisk.

Compact Flash is still around though, mostly enjoyed by professional photographers, who like it because due to its relatively large size it can contain a lot of flash chips and thus the enormous amount of data: nowadays a 512 GB CompactFlash is nothing special, enough to hold dozens of HD movies.note  It's also popular among hobbyists who found it very easy to connect to the old computers, as the CompactFlash interface is virtually identical to the IBM Personal Computer IDE hard disk interface and needs only a pin converter to look like a hard disk to an oldtimey PC.

The SD Card evolved from the Multimedia Card. Features included, as the name implies, security features to allow for write and password protection and DRM. Some physical features were added to enhance reliability. Otherwise the two standards are roughly the same

The SD Card has since gained some pretty amazing specifications since its debut in 1999. Micro SD Cards, which are the size of your pinky nail, can hold up to 200 GB, making it the most dense memory device in the world.