MCCI Corporation is constantly innovating. Cutting-edge solutions for mobile connectivity products, world-class support, solid standards compliance testing, and more...

USB Seminar in Tokyo

Toyo and MCCI's USB 3.0 seminar was held September 22 in Tokyo, Japan.  The seminar focused on developing and debugging USB 3.0 products. Toyo presented an overview of the USB 3.0 electrical and protocol specifications while MCCI CEO Terry Moore spoke on USB from a software perspective, emphasizing USB Attached SCSI (UAS), the new transport for mass storage devices that allows substantially improved performance over the previous mass storage specifications.

The USB 2.0 mass storage transfer mechanism, BOT (Bulk Only Transfer), doesn't allow overlapped operations and out-of-order completion, and therefore is not optimized for USB 3.0 speed. Not only are new host drivers required to take advantage of USB 3.0 throughput potential, different implementations are needed by different operating systems. The SCSIPORT driver is called by Win 2K and Win XP systems, but the StorPort driver is called by Vista and Win7.  MCCI ExpressDiskâ„¢ BOT and UAS drivers are optimized to exploit these distinctions.

USB 3.0 software development cannot neglect the extraordinary ubiquity of USB 2.0 hosts. They will present a major use case for the next year or two along with the billions of legacy devices in the field. The test matrix is huge.

Moore also discussed the new USB 3.0 host feature "streams." Because there is no official standard for streams, xHCI vendors that write their own software stack will force product makers who use streams to get access to vendors' proprietary APIs in order to test their drivers. A better approach is to use an "abstract API" that can be mapped onto any host stack. MCCI has published an abstract API that is free for anyone to use. Visit the USB 3.0 product page at to download it.