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Thursday, 20 February 2014

Multi Media Card (MMC) and Secure Digital (SD) Card

MultiMediaCard (MMC) is a flash memory card standard. Typically, an MMC is used as storage media for a portable device, in a form that can easily be removed for access by a PC.

Secure Digital (SD) is a flash 
(non-volatile) memory card format and is used for storage. MMC and SD cards differ in their physical size,capacity and their usage.

Both come in different memory sizes as well. While MMCs can be used in a standard SD card slot, the latter cannot be used in a MMC slot.

The Multi Media Card (MMC) is a flash memory card standard.
The Secure Digital (SD) Card is a flash memory card format.

MMC was developed by Siemens AG and SanDisk, and introduced in 1997.
SD Card was developed by Matsushita, SanDisk and Toshiba in 1999.

MMC are normally used as storage media for portable devices, such as digital cameras, cellular phones,digital audio players and PDAs.
SD card is used as a storage media in the following: Sony PS 3, Wii, GP2X GNU/Linux based portable games console, DAB radios, Global Positioning System receivers,Camcorders, cellular phones, digital audio players, PDAs etc.

The size of a standard MMC card is 24 mm x 32 mm x 1.4 mm while that of a SD card is 24 mm × 32 mm × 2.1 mm. So from the size comparison, we can see that SD cards are much thicker than the MMC cards, 2.1 mm against 1.4 mm.

SD cards are normally available in two more versions. They are miniSD and microSD. MicroSD is the smallest memory card available commercially. The size is 15mm × 11mm × 0.7mm. It is about 25% of the size of an SD card. With the help of adapters it can be used in those devices which are meant for SD, miniSD, or Memory Stick Duo cards; but they are not universally compatible.

MiniSD card was launched in 2003 and has ultra-small form factor extension to the SD card standard. These cards were designed especially for mobile phones; and packaged with a miniSD adapter through which it can also be used in devices that equipped with a standard SD Memory Card slot.
SDHC (Secure Digital High Capacity, SD 2.0), an extension of SD card, allows larger capacity, more than 2 GB. It uses the FAT32 file system which supports partition sizes greater than 2 GB. SDHC card has 3 different classes depending on their speed. Class 2 has speed of 2 MB/s, class 4 has 4MB/s, and class 6 has 6 MB /s. SDIO is another standard for SD card, which stands for Secured Digital Input and Output.

1 comment:

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