XD-Picture Card
Encyclopedia
xD-Picture Card is a flash memory card format, used mainly in older digital camera
s. xD stands for Extreme Digital.
xD cards are available in capacities of 16 MiB
up to 2 GiB.
, and introduced into the market in July 2002. Toshiba Corporation
and Samsung Electronics
manufacture the cards for Olympus and Fujifilm. xD cards are sold under other brand
s, including Kodak, SanDisk
, PNY, and Lexar
, but are not branded with the respective companies' logos, except for Kodak.
Before being phased out, xD cards were used in a select number of Olympus and Fujifilm
digital cameras and Olympus digital voice recorders. Fujifilm also made an MP3 player (xD-MP3) that used the cards. While many older Olympus and Fujifilm digital cameras use xD cards exclusively, some can access other memory card formats. In particular, Olympus Four Thirds and Fujifilm S3 Pro
digital SLRs have a slot for CompactFlash
cards in addition to xD. Newer Fujifilm FinePix cameras, including A, Z, S, and F series cameras, no longer use xD cards and only function with SD Cards. Some can accept SD, SDHC, and XD cards.
In March 2008, Olympus introduced an adapter (part number MASD-1) allowing its latest cameras to accept microSD cards in the xD slot. This adapter works only with recent models like Olympus μ9000
that were designed for it because the MASD-1 adapter is purely mechanical containing no electronic components, and thus relies on support for the SD card protocol within the cameras themselves, though this fact is not advertised by Olympus.
Olympus began to earnestly move away from the xD format with the release of the E-P1 camera, which only supports SD memory cards. The E-P1 memory specifications state that the only format supported is SD memory cards. As of Spring 2010, all new Olympus cameras announced at the 2010 Consumer Electronics Show and Photo Marketing Association International Trade Show
can use SD cards. Note that this changeover to the SD card format has never been officially announced by Olympus corporation.
Because of its higher cost and limited usage in products other than digital cameras, xD has lost ground to SD, which is broadly used by PDAs, personal computers, cellular phones, digital audio players and most other digital camera manufacturers. It is perhaps surprising that xD cards cost more than SD cards, since SD cards must contain a controller circuit in addition to the NAND flash memory. However, SD cards are produced in much greater numbers and by more manufacturers, so economies of scale
and increased competition
help explain the significant price disparity. Furthermore, the proprietary nature of xD cards allows Olympus and Fujifilm to charge extra for licensing.
(SD), CompactFlash
(CF), and Sony
's Memory Stick
.
(MLC) architecture to achieve a theoretical storage capacity of up to 8 GiB. , Type M cards are available in sizes from 256 MiB to 2 GiB. However, the Type M suffers slower read-write speeds than the original cards.
The Type H card, first released in November 2005, offers higher data rates than Type M cards (theoretically as much as 3 times faster). As of 2008, Type H cards were only available in 256 MiB, 512 MiB, 1 GiB, and 2 GiB capacities. Both Fuji and Olympus discontinued the production of Type H cards in 2008, citing high production costs.
The Type M+ card, first released in April 2008, offers data rates 1.5 times that of Type M cards. As of 2008, cards are available only in 1 and 2 GiB capacities.
Olympus says that its xD cards support special "picture effects" when used in some Olympus cameras, though these software features are not intrinsically hardware-dependent. Type H and M+ cards however, are required in newer models to capture video at high rate (640×480×30). Due to changes in the cards' storage architecture, newer Type M and H cards may suffer compatibility issues with some older cameras (especially video recording). Compatibility lists are available for Olympus: Olympus America's and Fujifilm's. The newer cards are also incompatible with some card reader
s.
by plugging the camera into the PC via a USB or IEEE 1394 cable, or by removing the card from the camera and inserting it into a card reader
. In both cases, the computer sees the card as a mass storage
device containing image files, although software or firmware can alter this representation. Card readers may be integrated into the PC or attached via cable. Adapters are available to allow an xD picture card to be plugged into other readers (and in some cases cameras), including PC card
, parallel port
, CompactFlash
and SmartMedia.
The memory format used by xD cards is not well documented. It is difficult to study it directly, since most camera devices and most USB card reader
s do not provide direct access to the flash memory. Since the cards are controller-less, cameras and card readers must perform wear leveling
and error detection themselves, and they normally hide the portion of the memory which stores this information (among other things) from higher-level access.
However, a few models of xD card readers based on the Alauda chip do allow direct access (bypassing the above mechanisms) to an xD card's flash memory; these readers have been reverse-engineered and Linux
driver
s have been produced by the Alauda Project, which has also documented the on-chip data structures of the xD card. According to this information, the xD card headers are similar to those used by SmartMedia, and include information on the manufacturer of the chip.
in an unusual package. Comparing the pinout of an xD card to the pinout of a NAND flash chip in a standard TSOP
package, one finds a nearly one-to-one correspondence between the active pins of the two devices. xD cards share this characteristic with the older SmartMedia
cards, which are also basically raw NAND flash chips, albeit in a larger package.
xD cards and SmartMedia cards can be used by hobbyists as a convenient source of NAND flash memory chips for custom projects. For example, the Mattel
Juice Box
PMP
can be booted into Linux using a modified cartridge containing an xD card with the boot image written to it. Additionally, SmartMedia and xD card readers can be used to read the data from NAND flash chips in electronic devices, by soldering leads between the chip and the card reader.
).
However, it appears that the card manufacturer information is simply stored in the flash memory, in the Card Information Structure (described in the Alauda Project's documentation, see above). Thus, it is possible to alter another brand of xD card to present itself as Olympus xD card by accessing the raw flash memory. One way to do this is by using a hacked device driver
for a USB card reader.
Digital camera
A digital camera is a camera that takes video or still photographs, or both, digitally by recording images via an electronic image sensor. It is the main device used in the field of digital photography...
s. xD stands for Extreme Digital.
xD cards are available in capacities of 16 MiB
Mebibyte
The mebibyte is a multiple of the unit byte for digital information. The binary prefix mebi means 220, therefore 1 mebibyte is . The unit symbol for the mebibyte is MiB. The unit was established by the International Electrotechnical Commission in 2000 and has been accepted for use by all major...
up to 2 GiB.
History
The cards were developed by Olympus and FujifilmFujifilm
is a multinational photography and imaging company headquartered in Tokyo, Japan.Fujifilm's principal activities are the development, production, sale and servicing of color photographic film, digital cameras, photofinishing equipment, color paper, photofinishing chemicals, medical imaging...
, and introduced into the market in July 2002. Toshiba Corporation
Toshiba
is a multinational electronics and electrical equipment corporation headquartered in Tokyo, Japan. It is a diversified manufacturer and marketer of electrical products, spanning information & communications equipment and systems, Internet-based solutions and services, electronic components and...
and Samsung Electronics
Samsung Electronics
Samsung Electronics is a South Korean multinational electronics and information technology company headquartered in Samsung Town, Seoul...
manufacture the cards for Olympus and Fujifilm. xD cards are sold under other brand
Brand
The American Marketing Association defines a brand as a "Name, term, design, symbol, or any other feature that identifies one seller's good or service as distinct from those of other sellers."...
s, including Kodak, SanDisk
SanDisk
SanDisk Corporation is an American multinational corporation that designs, develops and manufactures data storage solutions in a range of form factors using the flash memory, controller and firmware technologies. It was founded in 1988 by Dr. Eli Harari and Sanjay Mehrotra, non-volatile memory...
, PNY, and Lexar
Lexar
Lexar Media, Inc. is an American manufacturer of digital media products based in Fremont, CA. Products manufactured by Lexar include SD cards, Memory Sticks, keydrives, CompactFlash cards and card readers. Lexar's Memory Stick Duos also have versions adapted for the PSP which includes a version of...
, but are not branded with the respective companies' logos, except for Kodak.
Before being phased out, xD cards were used in a select number of Olympus and Fujifilm
Fujifilm
is a multinational photography and imaging company headquartered in Tokyo, Japan.Fujifilm's principal activities are the development, production, sale and servicing of color photographic film, digital cameras, photofinishing equipment, color paper, photofinishing chemicals, medical imaging...
digital cameras and Olympus digital voice recorders. Fujifilm also made an MP3 player (xD-MP3) that used the cards. While many older Olympus and Fujifilm digital cameras use xD cards exclusively, some can access other memory card formats. In particular, Olympus Four Thirds and Fujifilm S3 Pro
Finepix S5 Pro
The FinePix S5 Pro is a digital single lens reflex camera introduced by Fujifilm on25 September 2006 and since discontinued. It replaces the previous FinePix S3 Pro and keeps the Nikon F mount compatibility, including DX size lenses. It is based on the Nikon D200 body, and benefits from its...
digital SLRs have a slot for CompactFlash
CompactFlash
CompactFlash is a mass storage device format used in portable electronic devices. Most CompactFlash devices contain flash memory in a standardized enclosure. The format was first specified and produced by SanDisk in 1994...
cards in addition to xD. Newer Fujifilm FinePix cameras, including A, Z, S, and F series cameras, no longer use xD cards and only function with SD Cards. Some can accept SD, SDHC, and XD cards.
In March 2008, Olympus introduced an adapter (part number MASD-1) allowing its latest cameras to accept microSD cards in the xD slot. This adapter works only with recent models like Olympus μ9000
Olympus μ9000
The Olympus µ-9000 is the flagship model of Olympus' µ-Series line of point-and-shoot digital cameras. The µ Series consists of compact cameras characterized by small profiles, relatively great optical zoom function, and a focus on stylish outward appearance.- Specifications :- External links :* *...
that were designed for it because the MASD-1 adapter is purely mechanical containing no electronic components, and thus relies on support for the SD card protocol within the cameras themselves, though this fact is not advertised by Olympus.
Olympus began to earnestly move away from the xD format with the release of the E-P1 camera, which only supports SD memory cards. The E-P1 memory specifications state that the only format supported is SD memory cards. As of Spring 2010, all new Olympus cameras announced at the 2010 Consumer Electronics Show and Photo Marketing Association International Trade Show
Photo Marketing Association Annual Convention and Trade Show
The Photo Marketing Association International International Convention and Trade Show is an annual imaging technology trade show conducted by PMA held in Las Vegas. The PMA International Convention and Trade Show frequently are the occasion for the public introductions of important imaging products...
can use SD cards. Note that this changeover to the SD card format has never been officially announced by Olympus corporation.
Because of its higher cost and limited usage in products other than digital cameras, xD has lost ground to SD, which is broadly used by PDAs, personal computers, cellular phones, digital audio players and most other digital camera manufacturers. It is perhaps surprising that xD cards cost more than SD cards, since SD cards must contain a controller circuit in addition to the NAND flash memory. However, SD cards are produced in much greater numbers and by more manufacturers, so economies of scale
Economies of scale
Economies of scale, in microeconomics, refers to the cost advantages that an enterprise obtains due to expansion. There are factors that cause a producer’s average cost per unit to fall as the scale of output is increased. "Economies of scale" is a long run concept and refers to reductions in unit...
and increased competition
Competition (economics)
Competition in economics is a term that encompasses the notion of individuals and firms striving for a greater share of a market to sell or buy goods and services...
help explain the significant price disparity. Furthermore, the proprietary nature of xD cards allows Olympus and Fujifilm to charge extra for licensing.
Comparison with rival formats
, the xD format is obsolescent. New cards are still manufactured, but cameras supporting xD memory cards exclusively are no longer manufactured. Previously, xD competed primarily with Secure Digital cardSecure Digital card
Secure Digital is a non-volatile memory card format developed by the SD Card Association for use in portable devices. The SD technology is used by more than 400 brands across dozens of product categories and more than 8,000 models, and is considered the de-facto industry standard.Secure Digital...
(SD), CompactFlash
CompactFlash
CompactFlash is a mass storage device format used in portable electronic devices. Most CompactFlash devices contain flash memory in a standardized enclosure. The format was first specified and produced by SanDisk in 1994...
(CF), and Sony
Sony
, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....
's Memory Stick
Memory Stick
Memory Stick is a removable flash memory card format, launched by Sony in October 1998, and is also used in general to describe the whole family of Memory Sticks...
.
Advantages
- As it contains no flash translation layer (designed to emulate the block device structure of a magnetic disk drive), better-designed flash file systemFlash file systemA flash file system is a file system designed for storing files on flash memory devices. These are becoming more prevalent as the number of mobile devices is increasing, the cost per memory size decreases, and the capacity of flash memories increases....
s can directly access the NAND flash hardware. - As XD cards are very similar to a standard NAND chip, modified XD readers can be used to read arbitrary NAND chips.
Disadvantages
- All new Olympus and Fujifilm digital cameras use SD cards. Only the old generations of their digital cameras use xD cards.
- xD cards have a small maximum capacity relative to other memory card formats. First-generation xD cards have a maximum capacity of only 512 MiB; while Type M expands the theoretical maximum capacity to 8 GiB, but , there are no cards available with capacity greater than 2 GiB.
- xD cards have not kept up with the transfer rate, or speed, of other cards, notably Compact Flash and SD but also the later versions of the Memory Stick. The fastest xD card offers less than 10% of the speed of current (2009) Compact Flash cards.
- Although physically smaller than Secure Digital and Memory Stick cards, xD cards are larger than these competitors' reduced-size variants (microSD and Memory Stick Micro).
- xD cards are generally more expensive than other memory card types. , 2 GiB xD cards' retail prices are approximately three times those of same-capacity SD cards.
- xD cards are less widely supported by camera, card reader, and accessory manufacturers than other formats. , SD cards (and variants) are supported by all consumer-level digital cameras from major manufacturers. CompactFlash is the de facto standard for professional and prosumerProsumerProsumer is a portmanteau formed by contracting either the word professional or less often, producer with the word consumer. For example, a prosumer grade digital camera is a "cross" between consumer grade and professional grade...
cameras, accepted by virtually all digital SLR cameras, including those made by Olympus and Fujifilm. SD cards are also supported by many brands of MP3 players, PDAPDAA PDA is most commonly a Personal digital assistant, also known as a Personal data assistant, a mobile electronic device.PDA may also refer to:In science, medicine and technology:...
s, game consoles, and mobile phoneMobile phoneA mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...
s. - Because the xD is directly derived from the Smart Media card and is electrically identical (though not format identical) to that card, the xD card contains no wear levellingWear levellingWear leveling is a technique for prolonging the service life of some kinds of erasable computer storage media, such as Flash memory used in solid-state drives and USB Flash drives...
controller. Thus, the xD card may have a shorter life than comparable cards with FTL wear levelers if the file system used does not take into account wear leveling. - The xD card format is proprietaryProprietary softwareProprietary software is computer software licensed under exclusive legal right of the copyright holder. The licensee is given the right to use the software under certain conditions, while restricted from other uses, such as modification, further distribution, or reverse engineering.Complementary...
to Fujifilm and Olympus, just as the Memory Stick format is to Sony. This means that no public documentation or implementation is available (see below for reverse-engineering results). By comparison, the CompactFlash format is described by completely open and free specifications, and a partial specification for the SD format is freely available.
Type M/M+ and Type H cards
The original xD cards were available in 16 MiB to 512 MiB capacities. The Type M card, released in February 2005, uses multi-level cellMulti-level cell
In electronics, a multi-level cell is a memory element capable of storing more than a single bit of information.MLC NAND flash is a flash memory technology using multiple levels per cell to allow more bits to be stored using the same number of transistors...
(MLC) architecture to achieve a theoretical storage capacity of up to 8 GiB. , Type M cards are available in sizes from 256 MiB to 2 GiB. However, the Type M suffers slower read-write speeds than the original cards.
The Type H card, first released in November 2005, offers higher data rates than Type M cards (theoretically as much as 3 times faster). As of 2008, Type H cards were only available in 256 MiB, 512 MiB, 1 GiB, and 2 GiB capacities. Both Fuji and Olympus discontinued the production of Type H cards in 2008, citing high production costs.
The Type M+ card, first released in April 2008, offers data rates 1.5 times that of Type M cards. As of 2008, cards are available only in 1 and 2 GiB capacities.
Olympus says that its xD cards support special "picture effects" when used in some Olympus cameras, though these software features are not intrinsically hardware-dependent. Type H and M+ cards however, are required in newer models to capture video at high rate (640×480×30). Due to changes in the cards' storage architecture, newer Type M and H cards may suffer compatibility issues with some older cameras (especially video recording). Compatibility lists are available for Olympus: Olympus America's and Fujifilm's. The newer cards are also incompatible with some card reader
Card reader
A card reader is a data input device that reads data from a card-shaped storage medium. Historically, paper or cardboard punched cards were used throughout the first several decades of the computer industry to store information and programs for computer system, and were read by punched card readers...
s.
Theoretical transfer speeds
Pictures may be transferred from a digital camera's xD card to a personal computerPersonal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
by plugging the camera into the PC via a USB or IEEE 1394 cable, or by removing the card from the camera and inserting it into a card reader
Card reader
A card reader is a data input device that reads data from a card-shaped storage medium. Historically, paper or cardboard punched cards were used throughout the first several decades of the computer industry to store information and programs for computer system, and were read by punched card readers...
. In both cases, the computer sees the card as a mass storage
Mass storage
In computing, mass storage refers to the storage of large amounts of data in a persisting and machine-readable fashion. Devices and/or systems that have been described as mass storage include tape libraries, RAID systems, hard disk drives, magnetic tape drives, optical disc drives, magneto-optical...
device containing image files, although software or firmware can alter this representation. Card readers may be integrated into the PC or attached via cable. Adapters are available to allow an xD picture card to be plugged into other readers (and in some cases cameras), including PC card
PC card
In computing, PC Card is the form factor of a peripheral interface designed for laptop computers. The PC Card standard was defined and developed by the Personal Computer Memory Card International Association which itself was created by a number of computer industry companies in the United States...
, parallel port
Parallel port
A parallel port is a type of interface found on computers for connecting various peripherals. In computing, a parallel port is a parallel communication physical interface. It is also known as a printer port or Centronics port...
, CompactFlash
CompactFlash
CompactFlash is a mass storage device format used in portable electronic devices. Most CompactFlash devices contain flash memory in a standardized enclosure. The format was first specified and produced by SanDisk in 1994...
and SmartMedia.
| Type | Write speed (MiB/s) |
Read speed (MiB/s) |
Capacities Available | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 16 MiB | 32 MiB | 64 MiB | 128 MiB | 256 MiB | 512 MiB | 1 GiB | 2 GiB | |||
| Standard | 1.3 | 5 | ||||||||
| 3 | 5 | |||||||||
| M | 2.5 | 4 | ||||||||
| H | 4 | 5 | ||||||||
| M+ | 3.75 | 6 | ||||||||
Detailed specifications
The detailed specification for xD cards is tightly controlled by Olympus and Fujifilm, which charge licensing fees and royalties and require non-disclosure agreements in exchange for the technical information required to produce xD-compatible devices.The memory format used by xD cards is not well documented. It is difficult to study it directly, since most camera devices and most USB card reader
Card reader
A card reader is a data input device that reads data from a card-shaped storage medium. Historically, paper or cardboard punched cards were used throughout the first several decades of the computer industry to store information and programs for computer system, and were read by punched card readers...
s do not provide direct access to the flash memory. Since the cards are controller-less, cameras and card readers must perform wear leveling
Wear leveling
Wear leveling is a technique for prolonging the service life of some kinds of erasable computer storage media, such as Flash memory used in solid-state drives and USB Flash drives...
and error detection themselves, and they normally hide the portion of the memory which stores this information (among other things) from higher-level access.
However, a few models of xD card readers based on the Alauda chip do allow direct access (bypassing the above mechanisms) to an xD card's flash memory; these readers have been reverse-engineered and Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
driver
Device driver
In computing, a device driver or software driver is a computer program allowing higher-level computer programs to interact with a hardware device....
s have been produced by the Alauda Project, which has also documented the on-chip data structures of the xD card. According to this information, the xD card headers are similar to those used by SmartMedia, and include information on the manufacturer of the chip.
Raw hardware
At the raw hardware level, an xD card is simply an ordinary NAND flash integrated circuitIntegrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
in an unusual package. Comparing the pinout of an xD card to the pinout of a NAND flash chip in a standard TSOP
Thin small-outline package
Thin small-outline packages, or TSOPs are a type of surface mount IC package. They are notably very low-profile and have tight lead spacing ....
package, one finds a nearly one-to-one correspondence between the active pins of the two devices. xD cards share this characteristic with the older SmartMedia
SmartMedia
SmartMedia is a flash memory card standard owned by Toshiba, with capacities ranging from 2 MB to 128 MB. SmartMedia memory cards are no longer manufactured.- History :...
cards, which are also basically raw NAND flash chips, albeit in a larger package.
xD cards and SmartMedia cards can be used by hobbyists as a convenient source of NAND flash memory chips for custom projects. For example, the Mattel
Mattel
Mattel, Inc. is the world's largest toy company based on revenue. The products it produces include Fisher Price, Barbie dolls, Hot Wheels and Matchbox toys, Masters of the Universe, American Girl dolls, board games, and, in the early 1980s, video game consoles. The company's name is derived from...
Juice Box
Juice Box
The Juice Box is a low cost multimedia player made by toy manufacturer Mattel. The player features a screen with a native resolution of 240×160 px and runs μClinux, a microcontroller version of the Linux kernel. It has 66MHz ARM7TDMI architecture Samsung processor, 2 MBytes or 8 MBytes of RAM and...
PMP
Portable media player
A portable media player or digital audio player, is a consumer electronics device that is capable of storing and playing digital media such as audio, images, video, documents, etc. the data is typically stored on a hard drive, microdrive, or flash memory. In contrast, analog portable audio...
can be booted into Linux using a modified cartridge containing an xD card with the boot image written to it. Additionally, SmartMedia and xD card readers can be used to read the data from NAND flash chips in electronic devices, by soldering leads between the chip and the card reader.
Panoramic mode
Olympus-branded xD cards are the only ones that support Olympus cameras' panoramic function. Although they store data identically to other manufacturers' cards, Olympus intentionally disables this feature in the hopes that buyers will purchase their cards (a form of vendor lock-inVendor lock-in
In economics, vendor lock-in, also known as proprietary lock-in or customer lock-in, makes a customer dependent on a vendor for products and services, unable to use another vendor without substantial switching costs...
).
However, it appears that the card manufacturer information is simply stored in the flash memory, in the Card Information Structure (described in the Alauda Project's documentation, see above). Thus, it is possible to alter another brand of xD card to present itself as Olympus xD card by accessing the raw flash memory. One way to do this is by using a hacked device driver
Device driver
In computing, a device driver or software driver is a computer program allowing higher-level computer programs to interact with a hardware device....
for a USB card reader.