Secure Digital Memory Card (SD card in short), is a kind of new memory device based on semiconductor Flash Memory technology. It is widely used at portable units, such as DC, PDA, and multimedia player. SD card is developed by Panasonic, Toshiba, and SanDisk in August, 1999. The size of it is just like a stamp, and it only weighs 2g. It has very large memory capacity, high speed data transmission rate, great flexibility, and excellent security.
SD card combines SanDisk Flash Memory control
with MLC (Multilevel Cell) and Toshiba 0.16u, 0.13u NAND
technology together in its 24mm * 32 * 2.1mm size. It connects with special
driver through 9 pins port, and it needn't extra power to maintain the memorized
information. It is a unified solid dielectric, and it does not have any movable
part, so there is no need to worry about the damage of mechanical motion.
SD card is applied in the following
mobile digital devices:
● Digital camera. Save photos and videos.
Digital camcorder. Save photos and videos.
● PDA. Save all kinds of
● Mobile phone. Save photos, rings, music, videos, etc.
SD card is mostly used in MP3, DV, DC, etc, and also in
Notebook. The projected area is as big as MMC card, but a little bit thicker:
2.1mm. The capacity of SD card is much bigger, and the read-write speed is 4
times faster than MMC card. At the same time the port of SD card is compatible
with MMC card port. Most of the SD port also support MMC card. At present the
application of SD card is rapidly spreading and has a trend to predominate in
the DC camera market. This year the development of SD card is very fast and it
has threatened the market share of CF card. That is because the size of SD card
is much smaller than CF card, and the gap of capacity, performance, and price
between SD card and CF card is getting narrower. Recent years phones that
support SD card have been popular in the market. Therefore the rapid growing of
SD card is not accidental. The most important point is that MMC is compatible
with SD card. This is one of the reasons why SD card can get so popular.
However, in some production like mobile phone, SD card is not compatible with
MMC card. The capacity of SD card varies from 8MB to 32GB.
The size of SD card is very small.
Before buying it the consumer usually will not have much information about it.
It is a little difficult to identify from the appearance. Here are some ways to
identify the common brands SanDisk SD card: firstly, check the card to see if
there is laser chatoyancy label on the front side of pack. And the label will
change color with the different angles. Secondly, check the quality card of
agency. The pack is plastic, and it is the same with the one just mentioned. But
the "5 years guarantee" and Japanese on the right below have
been changed to image.
Besides, you can also check that if there are any
gaps on the bottom of the card. The number on the back pack of SanDisk SD card
is unique, and can be inquired by telephone. It is said the enquiry system has
not been built.
In 2006, the capacity of
SD card varies from 8, 16, 32, 64, 128, 256, or 512 MB, to 1, 2, 4, 6, 8,
SD/MMC card has replaced SM card developed by
Toshiba and becomes the most common digital memory card form of portable DC. In
2001, SM card takes 50% market share and then falls to about 40% in 2005 and
keeps falling. Most of DC producers provide SD card support including Canon,
Nikon, Kodak, Panasonic, and KONICA MINOLTA. Other three leading firms still
insist to use their patent forms: Olympus and Fuji use XD card, and Sony uses Memory Stick. Besides, SD card has not penetrated
into the DSLR market which CF card takes up the leading position. (D50
released by Nikon in 2005 support SD.) SD card is made by Toshiba by
adding encryption technology based on MMC technology. As MMC card may be used to
copy digital music by users, Toshiba adds this technology to make the music
industry feel safe. It is similar to Sony's MagicGate. Theoretically digital
copyright management can be added to encryption technology, but this function
has not been used very often. Users can use SD card through a USB card reader on
computer. Some new type computers have been installed with built-in card reader
device. The newest invention is building USB port in SD card and leaving out the
card reader. The design of SanDisk is adding a folding jacket to protect USB
port. Though SanDisk is not the first firm to add built-in USB port, because of
its important position, it still makes other firms to follow the trend. Actually
SD mark is firstly used in an entirely different way: it is firstly used at
"Super-Density Optical Disk". But this production of Toshiba
suffers defeat in the battle of DVD form. That's why the "D"
looks like "Disk".
SD series memory card is authorized by
SD card association after testing by SanDisk. Therefore almost all the paten
right is hold by SanDisk.
Mini SD and Micro SD
With the development of SD card storage technology, Mini SD and
Micro SD card have shown up.
Mini SD is
developed by Panasonic and SanDisk. For the convenience of more users to change
to use Mini SD, SanDisk has specially developed SD convert card. It can be used
with SD card DC, PDA, and MP3 at the same time. Mini SD is only 37% big as SD
card, but it still has the same read-write function and large capacity of SD
card. It is compatible with SD card. Through the SD convert card it can be used
as normal SD card.
SD card association
firstly brings T-flash into the subminiature storage card production family, and
named it Micro SD. After the release of nail big Micro SD, the consumers are all
amazed by it. And now many phones are using this kind of memory card. MMC micro
and Micro SD rank together the smallest mini memory card in the world. With the
super mini size and greater advantages, it can be used in all kinds of digital
production and doesn't waste much space of products' inside design. It is so
popular among the designers and helps to make exquisite digital life a lot.
There is a switch at the right side
of SD card: overwrite-protect switch. MMC card does not have this switch. When
the switch is turned down, SD card is protected from overwriting, and the
information on the card can be read only. When the switch is turned on, the card
can be overwritten again.
For more information: http://www.data-recovery-app.com