Secure Digital

Name	Secure Digital
Caption	Pair of SD cards
Type	Memory card
Capacity	Standard SD: 1 MB to SDHC: 4 GB to 32 GB SDXC: 32 GB to 2 TB
Owner	SD Card Association
Use	Portable devices, including digital cameras and handheld computers
Extended from	MultiMediaCard (MMC)
Dimensions	32 × 24 × 2.1 mm

Secure Digital (SD) is a non-volatile memory card format developed by Panasonic, SanDisk, and Toshiba for use in portable devices. It is widely used in digital cameras, digital camcorders, handheld computers, netbook computers, PDAs, media players, mobile phones, GPS receivers, and video game consoles. Standard SD cards have an official maximum capacity of 2 GB, though commercially they can store up to 4 GB. SDHC (High-capacity) cards have a maximum capacity of 32 GB. SDXC (eXtended Capacity) allows for up to 2 TB cards.

The format has proven very popular. Changes to the interface of the established format have made some older devices designed for standard SD cards (up to 4 GB) unable to handle newer formats such as SDHC (more than 4 GB). All SD cards have the same physical shape, which causes confusion for many consumers.

History

chip on the left. The chip on the right is a flash controller.]] In 1999, SanDisk, Matsushita, and Toshiba first agreed to develop and market the SD (Secure Digital) Memory Card, which was a development of the MMC. With a physical profile of 24×32×2.1 mm³, the new card provided both DRM up to the SDMI standard, and a high memory density for the time.

The new format was designed to compete with Sony's Memory Stick format, which was released the previous year, and featured MagicGate DRM. It was mistakenly predicted that DRM features would be widely used due to pressure from music and other media suppliers to prevent piracy.

The signature SD logo was actually developed for another use entirely: it was originally used for the Super Density Disc, which was the unsuccessful Toshiba entry in the DVD format war. This is why the D resembles an optical disc.

At the 2000 CES trade show Matsushita, SanDisk, and Toshiba Corporation announced the creation of the SD Card Association to promote SD cards. It is headquartered in California and its executive membership includes some 30 world-leading high-tech companies and major content companies. Early samples of the SD Card were available in the first quarter of 2000, with production quantities of 32 and 64 megabytes available 3 months later.

In April 2006, the SDA released a detailed specification for the non-security related parts of the SD Memory Card standard. The organization also released specifications for the SDIO (Secure Digital Input Output) cards and the standard SD host controller. During the same year, specifications were finalized for the small-form-factor microSD (formerly known as TransFlash) and SDHC, with capacities in excess of 2 GB and a minimum sustained read/write speed of 17.6 Mb/s

Design and implementation

SD cards are based on the older MultiMediaCard (MMC) format, but have a number of differences:

The SD card is asymmetrically shaped in order not to be inserted upside down, while an MMC would go in most of the way but not make contact if inverted.

SD cards are thicker than MMCs. SD cards generally mete 32×24×2.1 mm³, but as with MMCs can be as slim as 1.4mm if they lack a write-protect switch; such cards, called Thin SD, are described in the SD specification, but they are non-existent or rare in the market as most devices requiring a slimmer card use the smaller versions of SD: miniSD or microSD.

The card's electrical contacts are recessed beneath the surface of the card, protecting them from contact with a user's fingers.

SD cards typically have transfer rates in the range of 80–160 Mb/s, but this is subject to grow, due to recent improvements to the MMC standard.

Devices with SD slots can use the slimmer MMCs, but standard SD cards will not fit into the slimmer MMC slots. miniSD cards can be used directly in SD slots with a simple passive adapter, since the cards differ in size and shape but not electrical interface. With an active electronic adapter, SD cards can be used in CompactFlash or PC card slots. Some SD cards include a USB connector for compatibility with desktop and laptop computers, and card readers allow SD cards to be accessed via connectivity ports such as USB, FireWire, and the parallel printer port. SD cards can also be accessed via a floppy disk drive with a FlashPath adapter.

Optional write-protect tab

When looking at the card from the top (see pictures) there is one required notch on the right side (the side without the diagonal notched corner).

On the left side may be a write-protection notch. If this is present, the card cannot be written. If the notch is covered by a sliding write protection tab, or absent, then the card is writeable. Because the notch is detected only by the reader, the protection can be overridden if desired (and if supported by the reader). Not all devices support write protection, which is an optional feature of the SD standard.

Some SD cards have no write-protection notch, and it is absent completely in the MicroSD and MiniSD formats.

Some music and film media companies (e.g., Disney) have released limited catalogs of records and/or videos on SD. These usually contain DRM-encoded Windows Media files, making use of the SD format's DRM capabilities. Such media are usually permanently marked read-only by adding the notch with no tabs.

File system

Like other flash card technologies, most SD cards ship preformatted with the or FAT 32 file system on top of an MBR partition scheme. The ubiquity of this file system allows the card to be accessed on virtually any host device with an SD reader. Also, standard FAT maintenance utilities (e.g., SCANDISK) can be used to repair or retrieve corrupted data, and some utilities can recover deleted files, providing that they have not been overwritten. However, because the card appears as a removable hard drive to the host system, the card can be reformatted to any file system supported by the operating system. Conversely, an SD card can contain an embedded operating system (such as a Live USB) to recover a corrupted host computer by natively booting from the flash media reader.

SD cards with 4 GB and smaller capacities can be used with many systems by being formatted with (4 GB only possible by using 64kiB clusters, and not widely supported) or FAT32 file system (common for file systems 4GB and bigger). Cards 4GB and bigger can only be formatted with a file system that can handle these storage sizes, such as FAT32.

SD cards are plain block devices and do not in any way imply any specific partition layout or file system thus partition schemes other than MBR partitioning and the FAT file systems can be used. Under Unix-like operating systems such as Linux or FreeBSD, SD cards can be formatted using, for example, the UFS, EXT3 or the ReiserFS file systems; under Mac OS X, SD cards can be partitioned as GUID devices and formatted with the HFS+ file system. Under MS-Windows and some unix systems, SD cards can be formatted using the NTFS and on later versions exFAT file system. However most consumer products will expect MBR partitioning and FAT16/FAT32 filesystem.

Fragmentation may slow down the effective write speed but the effect is tiny compared with that of fragmentation on hard drives. Defragmentation tools may be used. However, it is unnecessary to use any disk optimization tool because on an SD card the time required to access any block is the same. Defragmenting an SD card will wear the card out and is not normally recommended, as the number of writes, before failure occurs, is limited (often as few as ).

Transfer modes

At the physical level, SD supports at least three transfer modes: ;One-bit SD mode: separate command and data channels and a proprietary transfer format. ;Four-bit SD mode: uses extra pins plus some reassigned pins. ;SPI mode: Serial Peripheral Interface Bus, a simpler subset of the SD protocol for use with microcontrollers.

All cards must support all three modes, except for microSD where SPI is optional. The cards must also support clock frequencies of up to 25MHz for regular cards, and 50MHz for high-speed cards.

;UHS-I: The Ultra High Speed (UHS) symbol can be found exclusively on SDXC and SDHC products. SDXC or SDHC products with the UHS-I symbol offer the swiftest bus-interface speeds available today (2^nd week of June 2010), capable of supporting data transfer speeds up to 104 MB/s. UHS-I quadruples the extant top speed of 25 MB/s. UHS bus interfaces are backwards compatible. SDXC UHS-I and SDHC UHS-I memory cards can achieve best performance when paired with a UHS-I device and are designed to allow consumers to record HD resolution videos, plus perform other simultaneous recording functions.

;UHS-II: The standard raises the data transfer speed to a theoretical maximum of 312 MB/s.

DRM features

The digital rights management scheme embedded in the SD cards is defined as the Content Protection for Recordable Media (CPRM) by the 4C Entity and is centered around use of the Cryptomeria cipher (also known as C2). The specification is kept secret and is accessible only to licensees. This DRM has not been seen "in the wild" and few, if any, devices appear to provide support for it. DVD-Audio uses a very similar scheme known as Content Protection for Prerecorded Media (CPPM).

If an SD card is inserted into a Windows Phone 7, it "locks the card to the phone with an automatically generated key" so that "the SD card cannot be read by another phone, device, or PC". Symbian devices, however, are some of the very few which can perform the necessary low-level format operations on locked SD cards. It is therefore possible to use a device such as the Nokia N8 to reformat the card for subsequent use in other devices.

Super*Talent, a manufacturer of computer memory, has created the Super Digital card. They are the same in appearance and function as regular Secure Digital cards, but they lack the CPRM code commonly found in Secure Digital cards.

Compared to other flash memory formats

Overall, SD is less open than CompactFlash or USB flash memory drives; these are open standards which can be implemented free of payment for licensing, royalties, or documentation. (CompactFlash and USB flash drives may, however, require licensing fees for the use of associated logos and trademarks.)

However, SD is much more open than Memory Stick, for which no public documentation nor any documented legacy implementation is available. All SD cards (other than microSD) can, at least, be accessed freely using the well-documented SPI/MMC mode.

xD cards are simply 18-pin NAND flash chips in a special package and support the standard command set for raw NAND flash access. Although the raw hardware interface to xD cards is well understood, the layout of its memory contents—necessary for interoperability with xD card readers and digital cameras—is totally undocumented. The consortium that licenses xD cards has not released any technical information to the public.

Speeds

There are different speeds of SD card available. The official unit of measurement is the Speed Class Rating; an older unit of measurement is the × rating.

Speed Class Rating

The Speed Class Rating is the official unit of speed measurement for SD Cards, defined by the SD Association. The Class number represents a multiple of 8 Mb/s (1 MB/s), and meets the least sustained write speeds for a card in a fragmented state.

These are the ratings of some currently available cards: Toshiba also announced cards based on the new 3.0 spec.

On 1 June 2010, Pretec announced the new Class-16 HD-video grade SDXC 64GB card at Computex Taipei 2010.

× rating

The × rating is equal to 1.2 Mb/s. It is derived from the standard CD-ROM drive speed of 1.2 Mb/s. (approximately 150 kB/s) Basic cards transfer data up to six times (6×) the data rate of the standard CD-ROM speed (7.2 Mb/s vs 1.2 Mb/s). The 2.0 specification defines speeds up to 200×, but unlike the class rating system, does not mandate that ×-ratings measure the card's least sustained write-speed. So, typically, manufacturers provide ×-ratings based on maximum read/write speeds. Furthermore, for most cards, the fastest read speed is typically swifter than its fastest write speed, leading some manufacturers to use read-speed as the ×-rating measurement. Other vendors, such as Kingston, use write-speed.

This table lists common ratings, the minimum transfer rates, and the corresponding Speed Class.

{| style="margin:auto;" class="wikitable" |- ! valign="top" | Rating ! valign="top" | Read Speed
(Mb/s) ! valign="top" | Write Speed
(MB/s) ! valign="top" | Speed
Class |- style="text-align:right;" || 6× || 7.2 || || |- style="text-align:right;" || 10× || 12.0 || || |- style="text-align:right;" || 13× || 16.0 || 2 || 2 |- style="text-align:right;" || 26× || 32.0 || 4 || 4 |- style="text-align:right;" || 32× || 38.4 || 5 || |- style="text-align:right;" || 40× || 48.0 || 6 || 6 |- style="text-align:right;" || 66× || 80.0 || 10 || 10 |- style="text-align:right;" || 100× || 120.0 || 15 || |- style="text-align:right;" || 133× || 160.0 || 20 || |- style="text-align:right;" || 150× || 180.0 || 22 || |- style="text-align:right;" || 200× || 240.0 || 30 || |- style="text-align:right;" || 266× || 320.0 || 40 || |- style="text-align:right;" || 300× || 360.0 || 45 || |- style="text-align:right;" || 400× || 480.0 || 60 || |- style="text-align:right;" || 600× || 720.0 || 90 || |}

Openness of standards

and the bottom one is the NAND flash chip that stores the data.]]

Like most memory card formats, SD is covered by numerous patents and trademarks.

Three versions of the SD specification have been set: 1.0, 1.1 and 2.0. These were originally available only after agreeing to a non-disclosure agreement (NDA) that prohibited development of an open source driver, which generated consternation in the open-source and free software communities. However, the system was eventually reverse-engineered, and the non-DRMed sections of the memory cards could be accessed by free software drivers.

Since then, the SD Card Association (SDA) has made access to a simplified version of the specification available under a less restrictive license. Although most open-source drivers were written before this, it has helped them to solve some compatibility issues.

In 2006, the SD Card Association also released a simplified version of their host controller interface specification (not to be confused with the physical specification, which covers the actual cards and their protocol) and later also for physical layer, ASSD extensions, SDIO and SDIO Bluetooth Type-A specifications under a disclaimers agreement. Like the physical specification, most of the information had already been discovered before the public release and at least Linux had a fully free driver for it. Still, building a chip conforming to this specification caused the One Laptop per Child project to claim "the first truly Open Source SD implementation, with no need to obtain an SDI license or sign NDAs to create SD drivers or applications."

For the most part, the lack of a complete, open SD specification mainly affects embedded systems and laptop systems, since desktop users generally read SD cards via USB-based card readers. These card readers present a standard USB mass storage interface to memory cards, thus separating the operating system from the details of the underlying SD interface. However, embedded systems (such as portable music players) usually access SD cards directly, and therefore complete programming information is necessary. Desktop card readers are themselves examples of such embedded systems; the manufacturers of these readers have usually paid the SDCA for complete access to the SD specifications. Many notebook computers now include SD card readers not based on USB; device drivers for these essentially access the SD card directly, as in embedded systems.

Royalties for SD/SDIO licences are imposed for manufacture and sale of memory cards and host adapters (USD$1,000/year plus membership at USD$1,500/year) but SDIO cards can be made without royalties and MMC host adapters do not require a royalty. MMCs have a seven-pin interface; SD and SDIO have expanded this to nine pins and MMC Plus expands this even further with thirteen pins.

Types of MMC/SD cards

The SD card is not the only flash memory card standard ratified by the Secure Digital Card Association (SDCA). Other SD Card Association formats include miniSD, microSD (formerly known as TransFlash before ratification by the SD Card Association), and SDHC (Secure Digital High Capacity, for capacities above 4 GB–although, there are some card readers that cannot handle over 1 GB that are not SDHC). SDHC is not fully compatible with the format that it extends, in that SD devices that do not specifically support SDHC will not work with the newer cards.

The smaller miniSD and microSD cards are usable in full size MMC/SD/SDIO slots with an adapter (which must route the electrical connections as well as making physical contact). However, it is already difficult to create I/O devices in the SD form factor and this will be even more difficult in the smaller sizes.

As SD slots still support MMCs, the separately-evolved smaller MMC variants are also compatible with SD-supporting devices. Unlike miniSD and microSD (which are sufficiently different from SD to make mechanical adapters necessary), RS-MMC slots maintain backward compatibility with full-sized MMCs, because the RS-MMCs are simply shorter MMCs. More information on these variants can be found in the article about the MultiMediaCard standard.

It is also important to note, that unlike for data storage (which typically works everywhere an SD slot is present), an SDIO device must be supported and equipped with drivers and applications for the host system and usually does not work outside of the manufacturer's scope (which means, for example, that an HP SDIO camera usually does not work with PDAs for which it is not listed as an accessory). This behavior is often not expected by end users who typically expect that only the SD slot is required. Similar compatibility issues are sometimes seen with Bluetooth devices, although to a much lesser extent thanks to standardized Bluetooth profiles.

Most, possibly all, current MMC flash memory cards support SPI mode even if not officially required as failure to do so would severely affect compatibility. All cards currently made by SanDisk, Ritek/Ridata, and Kingmax digital appear to support SPI. Also, MMCs may be electrically identical to SD cards but in a thinner package and with an electronic fuse blown to disable SD functionality (so no SD royalties need to be paid). Some MicroSD cards do not support SPI mode.

MMC defined the SPI and one-bit MMC/SD protocols. The underlying SPI protocol has existed for years as a standard feature on many microcontrollers. The new protocol used open collector signaling to allow multiple cards on the same bus but this actually causes problems at higher clock rates. While SPI used three shared lines plus a separate chip select to each card, the new protocol allows up to 30 cards to be connected to the same three wires (with no chip select) at the expense of a much more complicated card initialization and the requirement that each card have a unique serial number for plug and play operation; this feature is rarely used and its use is actively discouraged in new standards (which recommend a completely separate channel to each card) because of speed and power consumption issues. The quasi-proprietary one-bit protocol was extended to support four bit wide (SD and MMC) and eight bit (MMC only) transfers for more speed while much of the rest of the computer industry is moving to higher speed narrower channels; standard SPI could simply have been clocked at higher data rates (such as 133 MHz) for higher performance than offered by four-bit SD — embedded CPUs that did not already have higher clock rates available would not have been fast enough to handle the higher data rates anyway. The SD card association dropped support for some of the old one-bit MMC protocol commands and added support for additional commands related to copy protection.

Compatibility issues with 4 GB and larger cards

Devices that use SD cards identify the card by requesting a 128-bit identification string from the card. For standard-capacity SD cards, 12 of the bits are used to identify the number of memory clusters (ranging from 1 to 4,096) and 3 of the bits are used to identify the number of blocks per cluster (which decode to 4, 8, 16, 32, 64, 128, 256, or 512 blocks per cluster).

In older 1.x implementations the standard capacity block was exactly 512 bytes. This gives 4,096 × 512 × 512 = 1 gigabyte of storage memory. A later revision of the 1.x standard allowed a 4-bit field to indicate 1,024 or 2,048 bytes per block instead, yielding up to 4 gigabytes of memory storage.

Devices designed before this change may incorrectly identify such cards, usually by misidentifying a card with lower capacity than is the case by assuming 512 bytes per block rather than 1,024 or 2,048.

For the new SDHC (2.0) implementation, 32 bits of the identification string are used to indicate the memory size in increments of 512 bytes. The SDCA currently allows only 26 of the 32 bits to be used, giving a maximum size of 32 GB. All SD cards with a capacity larger than 4 GB must use the 2.0 implementation at minimum. Two bits that were previously reserved and fixed at 0 are now used for identifying the type of card, 0: standard; 1: SDHC; 2, 3: reserved. Non-SDHC devices are not programmed to read this code and therefore cannot correctly identify SDHC or SDXC cards.

All SDHC readers work with standard SD cards.

Many older devices will not accept the 2 or 4 GB size even though it is in the revised standard. The following statement is from the SD Card Association specification:

Standard-SD cards (non-SDHC) with greater than 1 GB capacity

The SD Card Association's current specifications define how a standard SD (non-SDHC) card with more than 1 GB and up to 4 GB capacity should be designed. These cards should be readable in any SD 1.01 devices that take the block length data into account. Any 1 GB or lesser card should always work (so the key question is how one's reader handles block length).

According to the specification, the maximum capacity of a standard SD card is defined by (BLOCKNR × BLOCK_LEN), where BLOCKNR may be (4,096 × 512) and BLOCK_LEN may be up to 2,048. This allows a capacity of 4 GB. The main problem is that some of the card readers support only a block (or, sector) size of 512 bytes, so greater than 1 GB non-SDHC cards may cause compatibility difficulties for users of such devices.

SDHC cards with greater than 32 GB capacity

Similarly to the above, as of version 2.00 of the specification, (it is expected that the SDHC specification will be revised in the future to allow card capacities greater than 32 GB

SD and SDHC compatibility issues

The SDHC specification was completed in June 2006, but by that time, non-standard high-capacity (>1GB) SD cards (based on the older 1.x specification) were already on the market. The two types of storage cards were not interchangeable, creating some confusion among customers. SD and SDHC cards and devices have these compatibility issues : Devices that do not specifically support SDHC do not recognize SDHC memory cards. Some devices can support SDHC through a firmware upgrade. SDHC devices are backward compatible with SD memory cards. File System: SD cards are typically formatted with the FAT16 file system, while SDHC cards are typically formatted as FAT32.

SDXC

The Secure Digital Extended Capacity (SDXC) format was unveiled at CES 2009 (January 7–10, 2009). The maximum capacity defined for SDXC cards is 2 TB (2048 GB). The older SDHC cards also have a maximum capacity of 2 TB based on the card data structures, but this is artificially limited to 32 GB by the SD 2.0 specification. The first SDXCs being released are governed by an SD 3.0 specification (which also still specifies FAT32 and thus lower capacities), whereas higher capacity and faster SDXCs are expected to follow an SD 4.0 specification, which was due to be released in spring of 2010.

The maximum transfer rate of SDXCs which follow the SD 3.0 specification was announced as 832 Mbit/s (these are called UHS104 speeds however, as with SD and SDHC, it is still a plain block device and thus arbitrary partitioning and other file systems can be used, such as FAT32, NTFS, ext2, UFS, etc.

History

On January 7, 2009, SanDisk and Sony announced the joint development of the XC variant of the competing Memory Stick format, boasting the same 2 TB maximum capacity of SDXC.

On January 8, 2009, Panasonic announced plans for production of 64 GB SDXC cards.

On March 6, 2009, Pretec introduced the world's first SDXC card with a capacity of 32 GB and a read/write speed of 400 Mbit/s. At the introduction, there were no products compatible with the new memory card.

On August 3, 2009, Toshiba announced it will launch the world's first 64 GB SDXC Memory Card with a read speed of 480 Mbit/s. The 64GB card (THNSU064GAA2BC) was planned to be available in the spring of 2010. Toshiba card was available from April 13.

On January 6, 2010, Panasonic announced its first SDXC cards with 64GB and 48GB to be available in February (RP-SDW64GE1K and RP-SDW48GE1K).

On January 6, 2010, Sony announced the launch of Handycam HDR-CX55V with SDXC support.

On February 8, 2010, Canon announced the launch of the new EOS Rebel T2i Digital SLR camera, the first EOS model to support SDXC memory cards.

On February 19, 2010, Panasonic launched in Japan World's first available for consumers SDXC memory cards with 64GB and 48GB (RP-SDW64GE1K and RP-SDW48GE1K) together with USB card readers compatible with SDXC format.

On February 22, 2010, SanDisk launched its 64GB SanDisk Ultra SDXC card.

The first integrated SDXC card readers are available from JMicron and are expected to be used in laptops in 2010.

SDHC and SDXC compatibility issues

In the 3.0 specification, the electronic interface of SDHC and SDXC cards is the same. This means that SDHC hosts which have drivers which recognize the newly used capability bits, and have operating system software which understands the exFAT filesystem, are compatible with SDXC cards. The decision to label cards with a capacity greater than 32GB as SDXC and to use a different filesystem is due solely to the limitations in creating larger filesystems in certain versions of Microsoft Windows. Other operating systems, such as Linux, make no distinction between SDHC and SDXC cards, as long as the card contains a compatible filesystem.

SDHC and SDXC cards and hosts have these compatibility issues: SDHC hosts will only support the SDXC cards which use UHS104 speeds;< SDXC hosts are backward compatible with SD and SDHC memory cards.), Microsoft Windows 7, Windows Vista SP1+, Windows Server 2008 SP1+, Windows Server 2003 SP2 or SP3 with KB955704, Windows CE 6+, and Mac OS X Snow Leopard (Intel-based)

Secure Digital Input Output (SDIO)

An SDIO card is a combination of an SD card and an I/O device. This kind of combination is increasingly found in portable electronics devices.

Hosts that support SDIO (typically PDAs like the Palm Treo, but occasionally laptops or mobile phones) can use small hosts designed for the SD form factor, like GPS receivers, Wi-Fi or Bluetooth adapters, modems, Ethernet adapters, barcode readers, IrDA adapters, FM radio tuners, TV tuners, RFID readers, digital cameras, or other mass storage media such as hard drives.

A number of other devices have been proposed but not yet implemented, including RS-232 serial adapters, fingerprint scanners, SDIO to USB host/slave adapters (which would allow an SDIO-equipped handheld device to use USB peripherals and/or interface to PCs), magnetic strip readers, combination Bluetooth/Wi-Fi/GPS transceivers, cellular modems (PCS, CDPD, GSM, etc.), and APRS/TNC adapters.

SDIO cards are fully compatible with the SD Memory Card host controller (including mechanical, electrical, power, signaling, and software). When an SDIO card is inserted into a non SDIO-aware host, it will cause no physical damage or disruption to device or host controller. SPI bus topology is mandatory for SDIO, unlike SD Memory. Most of the SD Memory commands are supported in SDIO. SDIO cards can contain 8 separate logical cards, although currently, this is at most a memory and IO function. SD slots will take SD cards only. SDIO slots will take SD cards and SDIO cards.

SD cards with extra features

Various manufacturers have tried to make their SD cards stand out from the crowd in different ways SD Plus - A type of SD card made by Sandisk that has an integrated USB connector so it can be plugged directly into a USB port without needing any special card reader. This concept has proven successful and other companies started introducing similar designs branded as duo SD or 3 Way in the case of A-DATA's MicroSDHC to SDHC and USB all-in-one product, which was available in 2008 only. Capacity Display - In 2006, A-DATA announced an SD card with its own digital display that would show how much free space is left on the card. Eye-Fi, Inc. - Produces an SD card with Wi-Fi capability built in for 802.11g, 802.11b, and backwards-compatible 802.11n wireless networks and supporting static WEP 40; 104; and 128, WPA-PSK, and WPA2-PSK security standards. The card works with any digital camera with an SD slot and can transmit captured images over a wireless network. When not in range of a wireless network connection, the card makes use of its 2 GB capacity (EYE-FI-2 GB model) until the images can be transferred. Some models geotag their pictures.

Gruvi - A rare type of microSD card with extra DRM features

Pre-Loaded Content

Towards the end of 2000s many manufacturers saw the need to distinguish their SD cards from one another. One idea was to introduce pre-loaded content onto new SD cards.

SanDisk introduced their SlotMusic which enabled users to buy digital music files already loaded onto their cards.

Market penetration

with a 4 GB SDHC card]]

Secure Digital cards are ubiquitous in consumer electronic devices, and have become the dominant means of storing several gigabytes of data in a small size.

Devices such as netbooks, digital cameras, camcorders, PDAs, mobile phones, video game consoles and digital audio players as well as many others use them.

Smaller devices tend to use MicroSD, or MiniSD rather than full sized SD cards.

SD cards are not generally used in mass produced devices where only a small amount of storage is needed due to economic reasons, or where a very large amount of storage is required.

Digital cameras

SD/MMC cards have replaced Toshiba's SmartMedia as the dominant memory card format used in digital cameras. In 2001, SmartMedia had achieved nearly 50% use, but by 2005 SD/MMC had achieved over 40% of the digital camera market and SmartMedia's share had plummeted, with cards not being easily available in 2007.

At this time all the leading digital camera manufacturers use SD in their consumer product lines, including Canon, Casio, Fujifilm, Kodak, Nikon, Olympus, Panasonic, Pentax, Ricoh, Samsung, and Sony. Previously, Olympus and Fujifilm used xD cards exclusively, while Sony only used Memory Stick. , they have added SD functionality to all models released since then.

Some prosumer and professional camera models continue to offer CompactFlash, either on a second card slot or as the only storage, as it has historically offered a better price/capacity ratio and faster transfer rates.

Embedded systems

Unlike CompactFlash, none of the SD card variants supports ATA signaling, limiting their use as solid state drives unless a separate converter chip is used. Although embedded systems exist that use SD cards as their main storage mechanism, a special SD controller chip is often used. In September 2008, the SD Card Association announced the Embedded SD standard to be released in November.

A homebrew hardware hack has brought SD card support to the popular Linksys WRT54G router by utilizing spare GPIO pins on the router's processor and the Linux kernel's MMC module. Transfer speeds of can be achieved with this setup.

References

External links

Organizations

SD Association, sdcard.org

MultiMedia Card Association, mmca.org

Joint Electronic Devices Engineering Council, jedec.org

Specifications

SD Simplified Specifications, sdcard.org

SD Specifications, Part 1, Physical Layer Simplified Specification, v3.01, 2010, sdcard.org

Microsoft Extensible Firmware Initiative FAT32 File System Specification, 2000, Microsoft

Software

SD Formatter for SD/SDHC/SDXC, sdcard.org

Comparisons

Comparison of practically all Memory cards, hjreggel.net

SDHC Card comparison (german), hardware-infos.com

Interfacing

Interfacing to SD cards, great technical details

Interfacing AVR (Arudino) to SD cards, C source code

Interfacing ARM to SD cards, C source code

Interfacing MSP430 to SD cards, C source code, Michigan State University

Interfacing MAXQ2000 to SD cards, good technical descriptions, C source code, maxim-ic.com

SD card controller, Verilog source code, opencores.org

Category:1999 introductions Category:Computer storage devices Category:Solid-state computer storage media

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Kingston Micro SD Card Reader

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Published: 2010-01-14
Uploaded: 2011-02-28
Author: pimpyouriphone3g

KINGSTON USB 2.0 (Transflash) Micro SD Card Reader : Ebay Item : cgi.ebay.co.uk Price : US $4.25 (Approximately £2.64) Kingston Website : www.kingston.com Multi-Kit One card does fit all devices. This all-in-one media kit combines a single card with an adapter to give mobile users the compatible storage they need for all SD and USB compatible devices, including mobile phones, digital cameras, notebook PCs, media players and more. By offering three adapters with the microSDHC card as the centerpiece, users get the most versatile mobile gear that seamlessly converts to a Secure Digital (SDHC), miniSDHC or USB format with one card that can be used across devices to easily move photos, music, videos or data to your camera, mobile phone or computer. Ultra-portable and multifunctional Use the microSDHC card alone for plenty of removable storage for music, games, ring tones, photos, movies and other applications on mobile phones. Slip the microSDHC card into the miniSD adapter and transform it into a miniSDHC storage card to expand storage on personal media players, smartphones or MP3 players. Capture photos from your digital camera by making the microSDHC a full-size SDHC card with the adapter and then view images with SDHC-enabled readers or USB drives, digital photo frames or on your TVs SD slot. Quickly and easily save files on a notebook computer with a full-size SDHC slot when the SDHC adapter is used with the microSDHC card. The kit is backed by a two-year warranty on the <b>...</b>

Macworld Video: Create a SD card startup disk

Order: Reorder
Duration: 4:03
Published: 2009-06-26
Uploaded: 2011-01-23
Author: macworld

In this video, Macworld senior editor Roman Loyola will show you how to create a SD card startup disk for the 13- and 15-inch MacBook Pros. You'll need a SD card with a capacity of at least 8GB, and the OS installation disc that came with the laptop.

Eye-Fi WiFi SD Card Review - Tech Look

Order: Reorder
Duration: 4:12
Published: 2009-10-15
Uploaded: 2011-03-02
Author: getconnectedtvshow

GC hosts AJ Vickery and Mike Agerbo take a look at the Eye-Fi, a wireless SD card that will help you get rid of using a ton of messy cables. Season 6 - Episode 1 - Segment 1

Eye-Fi Wireless SD Card Review

Order: Reorder
Duration: 15:30
Published: 2007-11-06
Uploaded: 2010-12-25
Author: lockergnome

live.pirillo.com - The new Eye-Fi is an SD card that has 2GB of storage, and is also Wi-Fi available. You can transfer pictures immediately to the Eye-Fi service, and put onto online picture albums.

Unmount SD Card G1

Order: Reorder
Duration: 2:19
Published: 2009-09-04
Uploaded: 2011-02-20
Author: Docextreme1

Unmount SD Card G1 from your G1 device it's very simple to remove your Sd card from the T-mobile G1 this video will so you how to do just that

HTC HD2 Android from Nand, no SD card, no RootFS

Order: Reorder
Duration: 4:12
Published: 2010-10-08
Uploaded: 2011-02-06
Author: rajkosto

Using magldr 1.08 with hotfix and rajko.info android build. No SD card needed during boot, SD-aware froyo applications install without errors. Proper small initrd like on real Android devices, speeds up boot time and frees up 17.5MB of NAND space. Hopefully this first build i've made will be used as a base for many more to come. Build made using mksquashfs from squashfs 4.0 and mkyaffs2image from latest yaffs git + modification at pastebin.com EDIT: updated link to frg81 based cyanogen build with kernel with wifi fix included

How To Play Wii Games Off SD Cards Or USB Drives

Order: Reorder
Duration: 7:09
Published: 2009-05-27
Uploaded: 2011-03-03
Author: NerdHelpDesk

bit.ly - Unlock your wii with the easiest, fastest, and safest solution. ______if you haveing problems look here___ You will need- SD card homebrew channel USB or SD dedicated to games file pack-- download the file pack- www.megaupload.com how to add ISO's from your computer www.youtube.com --NOTE-- If you want to use USB devices in game, put the USB device or hub in the LEFT usb port, while the USB harddrive on the RIGHT! 4.2 problems look here(My NEW Video) www.youtube.com

Eye-Fi Geo SD Card

Order: Reorder
Duration: 13:09
Published: 2009-09-01
Uploaded: 2011-02-17
Author: mocciat

Review of the Eye-Fi Geo Wireless SD Card. Upload your photos wirelessly and have them geotagged even without a GPS enabled camera. www.eye.fi Also check out the BuyMeAniPhone giveaway at: www.buymeaniphone.com Follow us on twitter www.twitter.com Check out our monthly giveaways. Apply to become a guest reviewer. Follow me on Twitter at: www.twitter.com

[Brawl Hacks] Replace Music with SD Card - File Patch Code 3.5.1

Order: Reorder
Duration: 5:09
Published: 2009-07-09
Uploaded: 2011-02-23
Author: josegallardo89

Title says it all. It is now possible to replace Brawl's audio tracks with your very own music from an SD card. Phantom Wings is back with what might be the last revolution in Brawl hacking history (just trying to make it sound like a big deal :P ). He hinted that there might be just one...

Super Smash Brothers Brawl - Custom Music (SD Card + Homebrew Channel + GeckoOS)

Order: Reorder
Duration: 10:09
Published: 2009-07-16
Uploaded: 2011-03-03
Author: MAST3RLINKX

Ever wanted to listen to your own music in Brawl? Without having to use your Ipod or burning a Brawl ISO with your music in it. Well now, thanks to PhantomWings, you can listen to your favorite music with just an SD Card, Homebrew Channel, and GeckoOS! All you have to do is convert your music from whatever format it is to WAV using a program like Audicity, then using the program BRSTM Converter to convert it to the format ".brstm" Then shove your .brstm file into \private\wii\app\RSBE\pf\sound\strm\(Music Number).brstm And you are almost ready! Almost ready? Why Almost, because you obviously need a code and that code can be found in this post below by PhantomWings: board.gscentral.org It's all exciting, I know... But, there are so many songs that you can replace, and it is time consuming if you have a bunch of songs you want to convert, or you don't have anything at all. So here, I present 207 Songs ready for your Brawl Put together by me. You must download both the below to fully obtain the 207 brstms. *Updated September 29th, 2009* Brstms A01 to M08: www.megaupload.com Brstms N01 to Z50: www.megaupload.com *THESE FILES TOGETHER ARE 1.12GB* So make sure you have a 2GB SD Card with enough space. This is one huge start for you, getting a head start with 207 songs, and being able to add and remove songs when you wish to! It also contains a Document I made telling you what song replaces what and the file name, AND EVEN LINKS TO THE ORIGINAL SONG in case you like the songs <b>...</b>

Does the SD Card Brand Matter?

Order: Reorder
Duration: 3:27
Published: 2010-08-10
Uploaded: 2011-02-10
Author: lockergnome

twitter.com - facebook.com - chris.pirillo.com - Over on Lockergnome, BMM2010 asked "Does a class and make (manufacturer) of an SD/micro SD card really make a difference?" The short answer is that yes - it does. I have always believed that you get what you pay for. If you think you're getting an amazing deal, you may end up with junk that will fail on you. Most of the time, you tend to get more bang for your buck. The class of an SD card determines how fast it is. A class 2 card, therefore, should not get the speeds of one that is a class 10... so don't believe the crap advertising telling you otherwise. chris.pirillo.com

EXT2 Android Partitioning Memory / SD-Card for HTC Phones

Order: Reorder
Duration: 9:41
Published: 2010-06-17
Uploaded: 2011-02-28
Author: TheNeoPeek

This video shows how to partition your internal memory (HTC Diamond) or SD-Card (other HTC Phones). After following this video you will know how to create EXT2 partitions. Visit www.neopeek.com for more infos

Will it break? SanDisk SD Card Underwater Test

Order: Reorder
Duration: 4:18
Published: 2010-03-30
Uploaded: 2011-02-24
Author: DigitalRevCom

After an incredible news story about a camera with an SD card was found at the bottom of the sea a year after it was dropped, and the photos were still found to be retrievable, we decided to do our own test to see if they really are that tough. However, we thought we would do away with the camera and throw just the SD card in our very own fish tank. We dropped a SanDisk SDHC card along with a cheaper alternative. Watch the video to find out what happens.

HTC HD2 Android from NAND no sd card

Order: Reorder
Duration: 2:36
Published: 2010-10-06
Uploaded: 2011-01-10
Author: rajkosto

Just to shut up that idiot who said that NAND is read-only and that you still need SD card to run android...which is ENTIRELY FALSE. Also android mass storage mode works perfectly with no data corruption when all the partitions are on NAND, unlike before.

How to Partition Your SDCARD

Order: Reorder
Duration: 5:39
Published: 2010-12-22
Uploaded: 2011-02-21
Author: pocketnowvideo

Not long ago we showed you how to use ROM Manager to download, update, and flash a custom ROM on your Android-powered phone

HTC Desire - Howto Move Apps to SD Card

Order: Reorder
Duration: 2:26
Published: 2010-08-02
Uploaded: 2011-02-28
Author: arminelec

Today is August 1st 2010. In this video I show you how to move your apps from internal memory to SD card. I updated my HTC Desire to Android 2.2 (Froyo) earlier. Your comments are appreciated :) Thanks for watching! :) :: :: Do not text while driving!!! :: --- Phone Specifications: Model: . A8181 CPU Speed: . 1 GHz Platform: . Android 2.2 (Froyo) with HTC Sense Memory: . 512 MB ROM and 576 MB RAM Size and weight: . 119 x 60 x 11.9 mm, 135 grams Display: . 3.7-inch AMOLED touch-sensitive screen Network: . HSPA/WCDMA (900/2100 MHz), GSM/GPRS/EDGE (850/900/1800/1900 MHz) GPS: . Internal GPS antenna Connectivity: . Bluetooth 2.1, A2DP, FTP, OPP, and PBAP . Wi-Fi: IEE 802.11 b/g . 3.5 mm stereo audio jack . Standard Micro-USB Camera: . 5 megapixel Expansion Slot: . microSD card --- Background music: Nightwalk by freeplaymusic freeplaymusic.com --- Me: www.artarmin.com --- DFTBA

Eye-Fi Wireless SD Card with the GoPro HD Hero camera

Order: Reorder
Duration: 10:37
Published: 2010-11-16
Uploaded: 2011-02-26
Author: eyeofmineGoProHDHero

This is the amazing Eye-Fi Pro X2 wireless SD Card that can transmit up to 200 feet with a router network or 90 feet with an ad hoc network. Combine that with an HD Hero GoPro camera and you've got a winning combination. WORKS ON MAC AND PC. For more information or to purchase, go to: www.eyeofmine.com/gopro/hd

Gaza flotilla video mashup: Internet Killed Israeli PR

Order: Reorder
Duration: 4:00
Published: 2010-08-11
Uploaded: 2011-03-02
Author: MinorDemogrphcThreat

Parody of Video Killed the Radio Star (Buggles) by Minor Demographic Threat. Useful links: www.bdsmovement.net & http for BDS & Palestine activism resources & news, www.artistsagainstapartheid.org to learn more about creative resistance to Israeli Apartheid. Please share extensively! Lyrics You had them on your wireless saying, 'Death to Jews' You sliced & diced & circumcised & claimed Fair Use 600 Turks were singing 'Girl U Know It's True' YouTube & Reddit, Twitter, Facebook, bit.ly You spammed them all & then you even posted 3 Casual Encounters on CraigsList NYC IDF spokesmen Who freakin' trained them? Bloggers came & broke your heart Now you tweet your new surveillance video Cyborg Al-Qaida from the future snorting blow set to the theme music from Hawaii Five-O He had a knife and Wait a second: that's Barbra Streisand You couldn't find my SD card You're in a bind says Michael Sfard The Shin Bet mined my SD card & played it back on NPR Born & raised in Arkansas I brought 6 nukes for the Hamas We are the Mavi Marmara You are the sloppy hasbara

Humminbird Software Update to SD Card using Humminbird PC

Order: Reorder
Duration: 7:27
Published: 2010-01-31
Uploaded: 2010-10-09
Author: rgecy

How to Upload a Humminbird Software Update to SD Card using Humminbird PC. This video shows you how to download a software update for your Humminbird Unit and upload it to an SD card with Humminbird PC.

Formatting SD card in windows to use Neopeek builds

Order: Reorder
Duration: 2:39
Published: 2010-08-25
Uploaded: 2011-03-01
Author: CnChenn

Recording program used: Camstudio Partitioning program used: MiniTool Partition Wizard Home Edition Operating system: Windows 7 Visit www.neopeek.com for neopeek Android builds (for supported HTC phones) If you have any comments, concerns, or if I did not do this correctly, please ask. Camstudio and MiniTool Partition Wizard Home Edition is freeware and is available free of charge. Format SD card into Fat32(however big, as long as you have ext2 and liuxswap), Ext2 (512 minimum..) and linuxswap (64mb). Please watch in 720p!

How to Insert a Micro SD Card - Blackberry Curve 8900

Order: Reorder
Duration: 2:24
Published: 2010-01-09
Uploaded: 2011-03-02
Author: donovanx3

Thanks for watching. Please SUBSCRIBE! Thanks!

G1 & MyTouch Tutorial - Partition SdCard w/ Amon Ra 1.3.2 - 1.6.2!

Order: Reorder
Duration: 3:55
Published: 2010-01-21
Uploaded: 2011-02-15
Author: ItsAndroidsWorld

SUBSCRIBE, RATE 5 STARS, AND DONATE TO ME BY CLICKING THIS LINK: www.paypal.com IF YOU LIKE YM VIDEOS, APPRECIATE WHAT I DO FOR THE ANDROID COMMUNITY, OR WANT TO HELP ME GET NEW EQUIPMENT AND ANDROID PHONES!!! FOLLOW ME ON TWITTER AT twitter.com/AndroidsWorld !!! THE BEST WAY TO CONTACT ME, AND WHERE I WILL POST ALL MY UPDATES !!!

WiFi and SD Card Access on JetDroid

Order: Reorder
Duration: 3:06
Published: 2010-12-04
Uploaded: 2011-02-22
Author: squidink14

As the title says, find out more here: www.jetdroid.org

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Kingston Micro SD Card Reader