From DailyTech: The Secure Digital eXtended Capacity (SDXC) format was announced almost a year ago at the 2009 International Consumer Electronics Show (CES). It was designed to replace ubiquitous Secure Digital High Capacity (SDHC) flash memory cards in computers, digital cameras, and other portable media devices. SDXC has a maximum theoretical capacity of 2TB using the exFAT file system and could eventually reach speeds as high as 300 MB/s. However, those speeds will only be realized with the Secure Digital Memory Standard 4.0 specification due in the spring. The new spec will add an additional serial pin in order to enable 300MB/s operation, but will still be backwards compatible with SDHC, SD, and MMC cards. The current SD 3.0 specification released in April will serve as a transitionary standard with added support for Ultra-High-Speed 104. UHS104 enables read and write speeds as high as 104MB/s, and is compatible with current SD 2.0 specification SDHC readers. There will be SDXC and SDHC cards using UHS104 during this transition. However, UHS104 SDHC cards will still be limited to 32GB due to the use of the FAT32 file system. Some card reader manufacturers are waiting for SD 4.0 to support SDXC, although JMicron is a notable exception. However, computer OEMs are eager to support SDXC and are already working on designs complying with SD 3.0 and offering support for UHS104. Toshiba has disclosed to DailyTech that its UHS104 SDXC and SDHC cards are already sampling to key OEMs. Its first SDXC offering is a 64GB card (THNSU064GAA2BC) capable of reading data at 60MB/s and writing data at 35MB/s. The company is also sampling 32GB and 16GB SDHC cards with those speeds. Mass production of all three is slated to start in the spring of next year. View: Article @ Source Site |