What is an SD Card? What are main Types of SD Cards

Manufactured as a competition offering to Sony’s Memory Stick, the SD Card was developed by the SD Card Association. This was a joint product by Toshiba, SanDisk and Matsushita. The Sony Memory Stick was launched in 1998. Toshiba, SanDisk and Matsushita launched the SD Card in 1999, but it was only in 2000 that it was produced by the SD Card Association. An SD Card is basically a memory card that stores data. It is handy and is meant for use in portable electronics like laptops, Digital Cameras, Digital Audio Devices and cell phones. The SD Card, is stored in a plastic cover and is an integrated circuit. It is meant to exchange data between devices that have SD Slots. It can also store a large amount of data in a compact manner.

SD Cards can be Standard SD Cards, SDHC Cards and the advanced SDXC Cards that are considered the future of Memory Cards. Each kind of memory card has a different speed. So, the user can select the card according to his requirement. The SD Cards have embedded DRM – digital rights management scheme in them in order to ensure Content protection for Recordable Media – CPRM. By this the content is protected and is available for use only to licensees, to prevent illegal copying. There is restricted copying from the card to the Computer.


SD Memory Card
It has a storage capacity of up to 2GB. The SD Cards use byte addressing.

SDHC Memory Cards
The SDHC – Secure Digital High Capacity Card’s capacity is from 4GB to 32 GB. The UHS – I and UHS Speed Class are available as the new bus interface specification for SDHC Cards. The SDHC Card uses sector addressing. Both newer and older formats are supported by SDHC memory cards. These memory cards bear SDHC trademark.

SDXC Memory Cards
The SDXC – Secure Digital Extended Capacity Card’s capacity is from32GB up to 2 TB. These cards were launched in 2009.they conform to SD 3.0 specification. Still further, future SD Cards will follow 4.0 specification. It is much faster and more efficient than the earlier kinds of memory cards. The SDXC Card allows users to store greater amount of content than before.

SDIO Memory Cards
A combination of SD and IO, is the SDIO Card. It is meant for smaller portable devices. Bluetooth, Wi-Fi Cards, TV Tuners, GPS Receivers, etc can be accommodated with the SDIO Card which extends the capacity of the SD Card.


SD Cards that have tried to differentiate themselves

SD Plus – The speciality of this card is that it has an inbuilt USB connector so that it can be connected to a laptop directly without an additional card reader being required.

Capacity Display – It was launched in 2006, with a digital display showing the amount of free space left on the card and the amount used.

Eye Fi – This card has the ability to transfer images directly over a wireless network since it has wi-fi capabilities. It works on any digital camera with a regular SD Slot.

Advancements in technology are unending and the growth of SD Cards have gone to show just that.