An anonymous reader writes "SD cards with a theoretical maximum capacity of 2TB are in development by Panasonic and the SD Association, it has been announced. The technology is called 'Secure Digital Extended Capacity', or 'SDXC', and Panasonic has announced it will soon show off a 64GB SDXC card. Using the new technology, read/write speeds are set to hit 300MBps. SanDisk and Sony are using the same standard to develop Extended Capacity cards in Sony's Memory Stick Pro and Memory Stick Micro range. SDXC utilises Microsoft's new exFAT file system — AKA 'FAT 64' — which first appeared in Windows Vista SP1, and has a theoretical file size limit of 16 exbibytes."
Reader xlotlu adds a note about the "proprietary exFAT file system, which is available for licensing under NDA. There are currently no specific patents on exFAT, but its legal status is uncertain since it's based on FAT. The FAT patents have been previously upheld in court."