XD card is known as XD-PICTURE CARD, XD from the "Extreme Digital", is "extreme digital" means. XD card is a relatively new type of flash memory card, compared to other flash memory cards, it has a Numerous advantages over other flash memory cards. Pocket-sized form factor, with dimensions of 20mm x 25mm x 1.7mm and a total volume of only 0.85 cubic centimeters, weighing about 2 grams, it is currently the world's lightest and smallest digital flash memory card. Excellent compatibility, with a variety of card readers, can be easily connected with personal computers. Large storage capacity, the theoretical maximum capacity of the XD card can be up to 8GB, with a lot of room for expansion. XD cards seen in the market today come in different capacity specifications such as 16MB, 32MB, 64MB, 128MB, 256MB, and so on. The xD card is a new type of memory card jointly introduced by Japan's Olympus Corporation and Fuji Limited, and has an extremely compact form factor, only as big as a postage stamp. The external dimensions are only 20 x 25 x 1.7mm, and the weight is only 2 grams. It can be considered the smallest in the field of memory cards. The xD card utilizes a single-sided 18-pin interface, with a theoretical image storage capacity of up to 8GB. In 2004, Fuji and Olympus jointly launched the xD card with a storage capacity of up to 1GB. And its read and write speed is also higher, (read rate of 5MB / S, write rate of 3MB / S or so) can meet the large amount of data written, power consumption is also lower, xD-Picture memory card can not only be used for personal computer adapter and USB card reader at the same time, so that it is very easy to connect with a personal computer, but also with the Compact Flash adapter and allow the use of Compact Flash cards as storage media in digital cameras. Although xD cards are currently a bit expensive, there is room for greater price reductions as the prices of flash memory chips and other memory cards continue to fall. Precautions for the use of xD cards (1) Try not to format the xD card with a card reader, as this may cause the card to be formatted incorrectly, preventing it from storing photographs and resulting in a crash. (2) When transferring images with a card reader, you should use the copying operation, not the cutting operation, and the deletion operation can only be done by the digital camera's own deletion function. Otherwise, it will also cause memory card failure. Currently on the market commonly seen xD card has three categories: standard, M type, H type The size of these three are the same, the difference lies in the technology used and the chip is different, so the speed is also different The earliest introduction of the xD card is the so-called standard, there is no controversy on this point, the standard test out of the value of the approximate read 5M / s, write 3M / s. M type is the use of MLC technology production, so that it can be used for the production of MLC technology, so that it can be used for the production of MLC technology production. The M-type is an xD card produced using MLC technology, which was released in 2005 to lower the price. However, it has encountered incompatibility problems with some older Olympus and Fuji models, and due to its slow speed (the biggest drawback of MLC), it often has problems with video recording, with values of about 4M/sec reading and 2.5M/sec writing in standard tests. D1KeT_t8cSFE-zri_OzWwNjxibxkHJdFFrdEG3taNZNr0SdjUw2xhZvhRstw67LaOpHSZy1aEtPRFxE0OHG6fved_Suk"> H-type, that is, the meaning of the HIGH-SPEED, read and write speeds than the standard type 2 times faster than M In this block, Fuji and Olympus respectively use different technologies to manufacture, Olympus's H-type XD card using the camera master to achieve the speed requirements of the point-and-shoot method, Fuji's H-type xD card with a different digital code in order to achieve the requirements of the increased speed (there are also Fuji's H-type xD card on the market using Olympus technology, presumably directly to the Olympus OEM). (there are also Fuji H-type xD cards on the market that use Olympus technology, presumably directly OEM'd from Olympus). It is important to note that there are limitations on the models that can be used with either the H or M type, so it is best to ask before you buy. A quick comparison Write: 9M JEPG Fine : 1.6 fps 4 sheets 15.0 sec (Sandisk Ultra II CF) ~9.8 sec (512 regular xD) 9.0 sec (1G xD type-H) Write: 9M RAW 1 sheet ~11.9 sec (Sandisk Ultra II CF) ~7.8 sec (512 normal xD) 6 - 6.5s sec (1G xD type-H) It seems that the effect is not as exaggerated as advertised Oh In addition, the xD card in the use of the card must also pay attention to (1) Try not to use a card reader to format the xD card, or may cause the card format error, so that the card can not be stored in the photo, resulting in the phenomenon of crash. (2) When transferring images with the card reader, you should use the copying operation, not the cutting operation, and the deletion operation can only be done through the digital camera's own deletion function. Otherwise, it will also cause the memory card to malfunction. Number of pictures that can be taken with an XD card 3 megapixels 4 megapixels 5 megapixels 6 megapixels 7 megapixels 8 megapixels 16MB 19 14 12 10 10 10 8 32MB 41 30 24 21 20 16 64MB 80 60 48 43 41 32 128MB 160 120 96 86 82 64 256MB 319 239 193 173 164 129 512MB 638 478 386 347 329 259 1GB 1276 956 772 694 658 518