xD-Picture Card is an obsolete flash memory card format, developed jointly by Olympus and Fujifilm in 2002 as a proprietary alternative to existing formats. It was primarily used in digital cameras produced by Olympus and Fujifilm, and was also adopted by Kodak in some models. xD cards were available in capacities ranging from 16MB[a] to 2GB.[b][1] While their file transfer speeds were good by 2002 standards, by the late 2000s they offered less capacity, were slower, and were more expensive than SD cards. The format was phased out in 2009, when Fujifilm and Olympus transitioned to the more widely supported SD card format.[2]
The cards were developed by Olympus and Fujifilm, and introduced into the market in July 2002. Toshiba Corporation and Samsung Electronics manufactured the cards for Olympus and Fujifilm. xD cards were sold under other brands, including Kodak, SanDisk, PNY, and Lexar, but were not branded with the respective companies' logos, except for Kodak. xD competed primarily with Secure Digital (SD) cards, CompactFlash (CF), and Sony's Memory Stick. Because of its higher cost and limited usage in products other than digital cameras, xD lost ground to SD, which is broadly used by cellular phones, personal computers, digital audio players and many other digital cameras.
Olympus included a bundled adaptor (MASD-1) with their cameras which allowed the use of microSD cards beginning with the FE-360 and FE-370 in August 2008.[3] These adaptors were included with, and are only compatible with, Olympus cameras released between August 2008 and August 2009.[4] Fuji did not release any such adaptor for use with their cameras. The MASD-1 adaptor only physically fits in compatible Olympus cameras. Forcing the adapter into an incompatible camera can damage the XD card slot. Some compatible cameras must have their firmware upgraded to version 1.1 or above in order to use the adaptor. Only SanDisk and Toshiba microSD cards from 256 MB to 8 GB in capacity were officially supported.[5]
Sticker on an Olympus FE-370 box showing the camera is compatible with xD cards and the included microSD adapter. Olympus abandoned this approach, as well as the xD card format, one year later
Olympus began to move away from the xD format with the mid-2009[6] announcement of the E-P1 camera, which supported only Secure Digital memory cards.[7] Higher-end DSLR cameras such as the E-3 and E-5 among others continued to use CompactFlash cards as well. The last Fujifilm camera which accepted xD cards was the Fujifilm FinePix F200EXR which was announced in February 2009. This camera also accepted SD cards.[8] The final Olympus cameras to use xD-Picture Cards were the FE-5020, FE-4010, FE-4000, FE-46 and FE-26, which were all released in August 2009.[9][10] xD cards were discontinued around the same time; AmazonBest Sellers in xD-Picture Cards reports no products offered with a Date First Available since 4 August 2009.[11][12] The abandonment of the xD-Picture Card format and changeover to the SD card format was not officially acknowledged by Olympus or FujiFilm.
Types
Four types of xD cards were produced over the format's lifetime. The first type had no type designation printed on the card but were retrospectively called Standard or Type S cards once other variants entered the market. Type M cards used multi-level cell technology to boost capacity at the expense of speed.[13] Type H (high speed) cards had the fastest write speeds of any xD card but were discontinued in 2008 due to high manufacturing costs.[14] The final type, M+ (which stood for enhanced type M) was introduced one year before Olympus and Fujifilm abandoned the format.[13]
The Type M card could achieve a theoretical storage capacity of up to 8GB. However, the Type M suffers from slower read/write speeds than the original cards. The Type H card offers higher data rates than Type M cards - theoretically as much as 3 times faster. Both Fuji and Olympus discontinued the production of Type H cards in 2008, citing high production costs. The Type M+ card offers data rates 1.5 times that of Type M cards.
Olympus claimed that its xD cards supported 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 later models to capture video at high rate (640×480 @ 30fps).[5] Due to changes in the cards' storage architecture, newer Type M and H cards may have compatibility issues with some older cameras (especially video recording). Compatibility lists are available for Olympus: Olympus America's[18] and Fujifilm's.[19]
Very similar to a standard NAND chip. Modified XD readers can be used to read arbitrary NAND chips.
Disadvantages
Card format is proprietary to Fujifilm and Olympus, just as the Memory Stick format is to Sony. No public documentation was available (see below for reverse-engineering results). In contrast, the CompactFlash format is described by completely open and free specifications.
Has not kept up with the transfer rate, or speed, of other cards, notably CompactFlash and SD, and the later versions of Memory Stick. The fastest xD card offers less than 10% of the speed of 2009-era CompactFlash cards.[citation needed]
Directly derived from the SmartMedia card. Thus, has no wear leveling controller. May have a shorter life span than comparable cards with FTL wear levelers if the file system used does not take into account wear leveling.
Generally more expensive than other memory card types. As of September2009[update], 2GB (2000MB) xD cards' retail prices were approximately three times those of same-capacity SD cards.
Small maximum capacity relative to other memory card formats.
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).
Less widely supported by camera, card reader, and accessory manufacturers than SD cards.
Many newer Olympus and Fujifilm digital cameras accept the more popular SD or CF cards, in addition to or instead of the xD format.
xD cards from the two main manufacturers, between the Olympus MASD-1 xD to microSD adapter card (microSD card below for scale)
Specifications
Detailed specifications are 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.[20]
The memory format used is not well documented. It is difficult to study it directly, since most camera devices and most USBcard readers 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. They normally hide the portion of the memory which stores this information (among other things) from higher level access.[21]
Reverse engineering
The back of an xD card, showing the 18 pinsUSB xD card reader
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 Linuxdrivers have been produced by the Alauda Project,[22] which has documented the on-chip data structures of the xD card.[23] According to this information, xD card headers are similar to those used by SmartMedia, and include chip manufacturer information.
Raw hardware
At the raw hardware level, an xD card is simply an ordinary NAND flashintegrated circuit in an unusual package. Comparing the pinout of a 18-pin to the pinout of a NAND flash chip in a standard TSOP package,[24] one finds a nearly one-to-one correspondence between the active pins of the two devices.xD card[24][25] xD cards share this characteristic with the older SmartMedia cards, which are also basically raw NAND flash chips, albeit in a larger package.
xD and SmartMedia cards can be used by hobbyists as a convenient source of NAND flash memory chips for custom projects. For example, the MattelJuice BoxPMP can be booted into Linux using a modified cartridge containing an xD card with a boot image written on 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.[26][27]
Panoramic mode
Some Olympus cameras offer camera-based panoramic processing. In those cameras that support both xD and CompactFlash cards, panoramic processing only works with images stored on the xD card, if installed. Newer Olympus cameras have neither xD cards nor this restriction.
Unsubtantiated reports claim that some cameras such as the E-450 only support panoramic processing when using Olympus branded xD cards. The model numbers have not been documented. In this case, there appears to be a workaround: it appears that the card manufacturer information is simply stored in the flash memory, in the Card Information Structure.[22][23] Thus, it is possible to alter another brand of xD card to present itself as Olympus xD card by accessing the raw flash memory. This can be done by using a hacked device driver for a USB card reader.[28]
↑ Olympus America Inc. – CCS Department. "Archived Products > E-P1". Olympusamerica.com. Archived from the original on December 22, 2010. Retrieved 2011-07-05. Memory: SD Memory Card(SDHC compatible) [xD cards are not included in entry]
↑ "Olympus Panorama Header". Robert Haus. 2007-12-09. Archived from the original on October 27, 2009. Retrieved 2011-07-05. Restore the panorama feature on Olympus smartmedia, with a hex editor, a Zio USB smartmedia reader, the smprep.exe program that is installed with it, and Windows 98/ME/2000.
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