USB Attached SCSI

Use of UAS generally provides faster transfers compared to the older USB Mass Storage Bulk-Only Transport (BOT) drivers.

To support these features, the Bulk Streaming Protocol was added to the USB3 specification, and Streams support was added to the USB host controller interface (Extensible Host Controller Interface).

[4] When used with an SSD, UAS is considerably faster than BOT for random reads and writes given the same USB transfer rate.

A brief hardware roundup in July 2010 by SemiAccurate found that Gigabyte Technology had introduced working UAS drivers for their boards using NEC/Renesas chips.

[1] A comparative performance review by VR-Zone in August 2011, concluded that only the NEC/Renesas chips had UAS working drivers.

[10] Of USB/SATA bridges, "the LucidPort USB300 and USB302, Symwave SW6315, Texas Instruments TUSB9261 and the VLI VL700 controllers all support UASP, while the ASMedia ASM1051 and ASM1051E as well as the Fujitsu MB86C30A doesn't.

[15] UAS drivers and products are certified by Microsoft using the Windows Hardware Certification Kit.

[16] Apple added native support for UAS to OS X 10.8 Mountain Lion; drives using UAS show up in System Information → Software → Extensions as IOUSBAttachedSCSI (or IOUSBMassStorageUASDriver, depending on the version of OS X) "Loaded: Yes".

[17] Drives listed with "Loaded: No" are defaulting to the older, slower Bulk Only Transport (BOT) mode.