About TF, SD, SDHC common sense
SD Card (Secure Digital Memory Card) MMC card is Toshiba added encryption hardware technology made it easier for the MMC card may allow the user to copy digital music and Toshiba have joined the music industry hope that these technologies peace of mind. Similar technology, including Sony's MagicGate, encryption technology can in theory introduce digital rights management,
With SD card storage technology, the gradual emergence of Mini SD and Micro SD card. MiniSD jointly developed by Matsushita and SanDisk. To facilitate more users can be converted to use different memory card mini SD, SanDisk also introduced the SD adapter specifically, you can now use SD cards with digital cameras, PDA handheld computers and MP3 music players shared use. Mini SD is only 37% of the size of SD card, but have the same SD memory card read and write performance and large capacity, and is fully compatible with standard SD card, SD adapter through the included SD card can also be used as a general .
TF card via SD card converter, when the SD card. SD adapter can be used as a storage medium using the devices. TransFlash primarily for large film camera phone images and video clips to download larger and developed. TransFlash cards can be used to store personal data such as digital photos, MP3, games and applications for mobile phones and personal data, but also in the
SDHC is a "High Capacity SD Memory Card" the acronym for "high-capacity SD memory card." May 2006 SD Association released the latest version of the SD 2.0 specification of the system, in which the provision is in line with the new SDHC standard, and less than or equal capacity greater than 2GB 32GB of SD card. The greatest feature is the SDHC high-capacity (2GB-32GB). In addition, SD Association provides SDHC FAT32 file system must be used, because the SD card before using the FAT16 file system supports a maximum capacity of 2GB, and can not meet the requirements of SDHC.
All SD cards larger than 2G capacity must meet the SDHC specification, the specification that at least meet the Class 2 SDHC speed rating, and must have the SDHC logo on cards and speed rating logo. There are some brands on the market to provide the 4GB or higher capacity SD card does not meet the above criteria, such as the lack of SDHC logo sign or speed rating, the SDHC memory card can not be called card, strictly speaking they are not SD Association recognized, these cards are likely to arise in the use of the device compatibility issues.
As with the SD1.1 SDHC specification using different addressing modes, it is not compatible with SD 2.0 specification stablished the production of some of the older version before SD devices, only the new SD line with SD2.0 specification equipment to use SDHC. If the SDHC into some of the older versions of SD devices, out of the card data protection purposes, will not be
The SD Association, mentioned above, the provisions of the speed rating (Speed Class), the test methods and general performance testing is quite different. Test based on the card were different degrees of fragmentation test read and write rate curve rate curve, not a single large file transfer speed tests. SD Association defines the minimum requirements to meet the level of performance curve, according to test data from the SD Association and to compare the prescribed performance standards, in order to determine the card's performance levels.
SD2.0 specification of performance for the SD card into the following four levels, different grades to meet different application requirements are:
SD Association, is based on the actual application of the various brands of SDHC speed grade products division, and currently on the market to offer 4GB SDHC Class 6 level can be described as very few vendors.