SD Card types
Ever since their introduction in 1999, SD cards have continuously been researched and developed as the most practical solution for mobile storage. The SD Card Association regulates the cards, and the presence of their logo on an SD card ensures that you are using an officially certified product, compatible with most devices available in the market.
Different SD card types developed as technology started requiring more and more storage, as applications and files increased in size.
SDSC cards were developed to improve the standard of the time, MMC. These cards had a storage limit of 2GB but at the time of their development that was quite an impressive value. The SDSC cards also featured an asymmetrical design to prevent users from inserting them the wrong way and damaging their devices. The cards also featured security circuitry for digital rights management content protection.
Released in 2006, the Secure Digital High Capacity format presented the world with an upgraded version of the storage card. SDHC is considered to be the 2.0 version of the storage card. The storage limit was bumped up to 32GB despite having the same physical and electrical construction. These cards sometimes have incompatibilities with older storage cards, and this is due to the extensive modifications made to the CSD register.
The Secure Data eXtended Capability format was released in 2009, defining the 3.01 specification of SD cards. These new cards support storage up to 2TB, which is an incredible amount of storage in such a small form factor. Besides the extended storage, the SDXC format brought many new features such as the Ultra High-Speed bus which allowed for faster data transfers of up to 104 Mbyte/s.
SDXC How to format an SD Card