USB 1.1 was developed as an inexpensive means for serial data transfer between a host computer and external devices. The device-end physical interface can be very low cost and is often integrated into the device’s microcontroller. (This is seen with some USB mouse and keyboard products). It’s barely tolerable for file transfer, however. USB 2.0 was developed to enable much faster performance during backup of internal drives and large file transfers. USB 2.0 is also backward compatible with USB 1.1 host systems and hubs (at USB 1.1 speeds).
In late 2009 Western Digital released our first USB 3.0 drive. USB 3.0 is significantly faster than USB 2.0. USB 3.0 is backwards compatible with USB 2.0 controllers, switches and hubs(at USB 2.0 speeds).
