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An SD Memory Card (short for Secure Digital Memory Card, Secure Digital Memory Card) is a digital storage medium that uses the principle of flash storage.

The SD Memory Card was developed in 2001 by SanDisk, based on the older MMC standard. The name derives from Secure Digital extra hardware functions for the Digital Rights Management (DRM from). By means of a key stored in protected memory area to prevent the illegal Memory Card playing of protected media files. The encryption is based on the procedure of the 4C CPRM consortium which is also in a similar way (CPPM) at the DVD-Audio uses. The exact specification is under lock and can only be seen by the Association paying licensees of the SD Memory Card.

The Memory Card has a built-in "controller". It is 32 mm × 24 mm × 2.1 mm in size and had to start a capacity of 8 megabytes. Subsequent Memory Cards doubled the storage space in each case (16, 32, ... MB), so that today announced capacities of 32 GB available and 64 GB5.Exceptions in this scheme is 6 GB and 12 GB comprehensive maps, which currently (as of April 2009) only produced by .

On the side of an SD Memory Card is a small slider is for setting the write protection. This slide is no protection mechanism at the Memory Card itself, but is only recognized by the Memory Card holder and analyzed by the . Usually it takes is a sufficiently dense layer of tape instead of the write-protect slider to damaged Memory Cards back to describe them. The readers typically use a metal buyer for status to be depressed by a sufficient force at the position "writable" must.

The Consortium for SD Memory Cards only defined a Memory Card capacity of up to 1 GB (SD 1.0) and 2 GB (SD 1.1). Memory Cards with a capacity of 4 GB, which are as SD Memory Cards (not SDHC sold) do not comply with the specifications and, most particularly in some older devices sometimes cause problems, they also work in some SDHC devices (for example, in some Lumix models from Panasonic not). Devices that only support SD 1.0 (older Memory Card reader, and often newer notebooks internal) 2-GB Memory Cards read sometimes, but cause some errors in the storage area above 1 GB, such as spelling errors. Often, the Memory Card will simply appear as a 1 GB and partition.

SDHC (SD 2.0)

The actual memory chips often require only a small part of the housing

An extension of this specification makes storage capacities up to the maximum capacity of 32 GB, under the designation SDHC (SD High Capacity). SDHC Memory Cards do not work in devices that can deal only with SD Memory Cards. Since this is not always recorded on the devices, you should test the interaction between Memory Card and reader before buying. The dimensions are similar to those of SD Memory Cards.

In addition, sets the SDHC specification defines performance classes, which establish guaranteed minimum rates for the recording of MPEG data streams: For maps of class 2 is 2 MByte / s, with Class 4 4 MB / s, Class 6 is 6 MByte / s and Class 10 there are at least 10 MByte / s. AVC-HD cameras usually require at least 1 MByte / s, the Panasonic HDC-SD1 as 13 Mbit / s, 1.6 MB / s, which then class 2 would www.mytrendyphone.co.uk

be sufficient. Higher data rates are advantageous for the continuous shooting of digital cameras and transfer to the PC. Under this scheme, the classes on the SDHC Memory Cards are printed with at least one of the numbers 2, 4, 6 or 10 with an open circle to the right (see photos). The previous SD specifications before seen such a universally applicable standard for all manufacturers not to transfer.

In August 2006 the first 4-GB SDHC Memory Card came on the market in early 2008, the world's first class-6 Memory Card, followed by 32 GB, in December 2009, the 10-class Memory Card .

As primarily intended for use in digital cameras, SDHC Memory Cards are usually formatted with the FAT32 . Therefore, they are with older cameras that only understand the (at SD Memory Cards 1.x usual) FAT16 format, not compatible. For the use in older cameras, it is possible to format SDHC Memory Card with FAT16, but this limits the usable capacity of 2 GB and 4 GB. In principle, SD Memory Cards (and thus also SDHC Memory Cards) are not limited to the FAT file system. It is no problem, she with UFS, ZFS, ext3, NTFS to use what these media makes it interesting because of its size as a replacement for USB sticks and for use in digital camcorders. It should be noted however, that it will usually be in digital cameras can not be addressed and a Memory Card error is reported.

SDXC (SD 3.0)

Speed-Class 6 memory speed has a minimum of 6 megabytes per second

At the Consumer Electronics Show 2009 announced the SD Memory Card Association to the successor of SDHC. The specification of the SDXC (eXtended Capacity SD) Memory Cards listed allows one size to 2 TB (2,048 GB). The division is maintained in power and now extends to 104 MB / s, with plans to 300 MB / s. As a file system that comes on optimized exFAT by Microsoft for use. are drivers for Microsoft's exFAT it on Windows 7, Windows Vista with Service Pack 1 and Windows XP is available from Service Pack 2, a separate update. Using a patent sharing agreement with Microsoft is to Tuxera indicated that working to develop a exFAT driver for embedded . Whether these drivers will be released but as Tuxeras NTFS-3G in accordance with the principle of both dual-licensing under a commercial license, or under an open-source license is not known.

Other file systems like FAT32 are also possible, to ensure compatibility with older devices.exFAT Memory Cards are not compatible with SDHC or SD Memory Card readers or hosts. Moreover, the transfer rates exceed the capabilities of the USB 2.0 standard, so it is useful to equip future devices with USB 3.0.

Pretec On 6 March 2009, the first SDXC memory with a storage capacity of 32 GB and a write and read speeds of 50 MB / s presented. Panasonic brought in early 2010 maps with 48 and 64 GB on the market. The first devices, SDXC the support are already available on the German market.

Designs

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miniSD

For small devices, the miniSD was developed. It is equipped with 20 mm × 21.5 mm × 1.4 mm, about half the size of the SD Memory Card. Using a common purchase included adapter, it fits in any standard SD slot. These little Memory Cards are currently available with a storage capacity of 32 MB to 16 GB (miniSDHC). Since September 2009, the production has been set but as far as possible and is therefore available only in remnants!

Micro SD Memory Card with Adapter

The microSD Memory Card (formerly known under the name Trans Flash) is again smaller than the miniSD. She has worked with 11 mm × 15 mm × 1.0 mm just the size of a fingernail and 2005 is the smallest flash Memory Card in the world. MicroSD Memory Cards are currently with a storage capacity to 32 GB (microSDHC) offered .

Both miniSD and microSD via adapter can be brought down to SD Memory Card format. A microSD Memory Card can also be placed via adapter to miniSD format.

SD Memory Card with USB port and without cover

Since January 2005 there are special SD Memory Cards have an integrated USB port and therefore be connected without an adapter or Memory Card reader to a USB connector type A can. The USB port is mostly concealed by a cover which can be either folded or removed.

Since mid-2008 there are SD Memory Cards with integrated Wi-Fi function. These are sold under the trade name Eye-Fi Memory Card. Depending on the Memory Card type to be PC Sync, Internet upload via WiFi hotspots or wireless access points possible, not to mention saving the geographical data of the recording venue. They have the same form factor as SD Memory Cards and fit in most camera models. Possible geo-coordinates were taken from a database of local wireless stations (Skyhook) and are added when passing the pictures through the Internet, the EXIF data.

The microSD Memory Cards since 2009 and USB adapters are available.

Transmission speed

SD-board with two memory banks

Was initially read the transmission rate at about 3.6 MB / s () and write 0.8 MB / s (), so even cheap tickets now get a write speed of up to 9 MB / s. The so-called high-speed Memory Cards now achieve up to 30 MB / s when writing. www.mytrendyphone.co.uk

One way to increase the writing is the use of two parallel-addressed memory banks, as here opposite the example of a 2-GB Memory Card EXTREMEMORY that in the current (2008) referred PERFORMANCE series 15 MB / s can be.

The maximum values fluctuate greatly and are dependent on the manufacturer and the equipment used to use. The transmission speed is usually not given directly, but rather as a factor based on the reading speed of CDs (= 150 kB / s for the original single-speed or 1x drives). This notation has been disseminated on the basis of CD burners for other recordable media. Example: High Speed SD Memory Card 50x = 7.5 MB / s write speed. It should be noted that a too low write speed of memory performance for devices with a rapidly processed, high data volume may limit disturbing. With digital cameras, the maximum refresh sequence below the manufacturer's instructions, and when taking videos under certain circumstances, the possible resolution may be limited.

Speed classes

In the SD 2.00 specification, the following "Speed classes are defined.

Class 2: 16 Mbit / s (2 Mb / s)

Class 4: 32 Mbit / s (4 MB / s)

Class 6: 48 Mbps (6 MB / s)

Class 10: 80 Mbit / s (10MB / s) (only later in Version 3.0)

SD SD-HC I and I-XC: 104 MB / s - Ultra High Speed (UHS)

Maximum number of write operations

USB Memory Card reader for SD and MMC Memory Cards

Because of the memory technology used in flash memory is not always as often described. However, all Memory Cards have an algorithm for defect scattering, by a much longer period of use can be achieved. These write requests are redirected to a logical block of the medium to changing physical memory areas (English "wear leveling"), so that for example the frequent writing of file system tables are not always held to the same memory cells and can make these early unusable. However, the methods used are generally not disclosed and recorded infrequently on the products, so there is hardly a choice for longevity. The estimated lifetime is specified at SLC NAND chips with 1,000,000 access, the use of MLC NAND chips with 100,000 write operations. According to investigations of the magazine these numbers are irrelevant, however: in a months-term experiment with USB sticks, it was not even a stick by writing it to destroy the same sector. Read accesses to flash memory are independent is unlimited.

In addition to the limitation of writes any SD Memory Card can, of course, like any other technical equipment break down as well. These include in addition to losses due to aging as electrical damage (ESD, often falls "only" to the controller Memory Card, not the flash itself) such as mechanical damage (damage due to insertions, damage due to bending of the Memory Card). www.mytrendyphone.co.uk

Use

SD Memory Cards are used in many different devices. Often they come to take photos in digital cameras, MP3 players for playback of MP3 files and in PDAs and cell phones are used for different applications. Mobile navigation systems use SD Memory Cards to store maps of the country, and also use some handheld consoles SD Memory Cards.

Devices with SD slot are generally backward compatible with MMC Memory Cards. Thus, MMCs can usually operate in devices designed for SD Memory Card. However, fast-MMC Memory Card in SD pure- readers are not dealt with at full speed, this is a full MMC support needed. The operation of SD Memory Cards in devices that are designed only for MMC but it is not possible. In order to avoid wrong use, SD Memory Cards have a slightly thicker housing than MMC Memory Cards. Therefore, SD Memory Cards fit because of its thickness usually not in MMC slots.

Apart from the digital photography with high resolution and faster frame rate, or the inclusion of videos is not for most devices and application purposes, the use of high-speed SD Memory Card required. SDIO-compatible Memory Card slots (SDIO stands for "SD Input / Output") also allow the connection of other devices (radio, camera, W-LAN).