Introduction
Nowadays, the number of devices is getting bigger and bigger, and modern operating systems must try to support all types and several of them with every integration, with every release. Maintaining a large number of devices is difficult, expensive and also hard to test, specially for plug-and-play devices, like USB devices.
Therefore, it is necessary to create a mechanism to facilitate the maintenance and testing of old and new USB devices. And this is where USB device emulation comes in. In that way, a complete framework including a big bunch of emulated and validated USB devices will allow easier integration and release. The area of application would be very wide: earlier bug search/detection even during development, automatic tests, continuous integration, etc.
Original article from:
This is place to get going virtual devices on Ouya. Some keywords sofar:
Umockdev mocks hardware devices for creating unit tests for libraries and programs that handle Linux hardware devices.
All can jump in and talk about topic, do you know anything or not is not that inportant.
EDIT:
Interesting video about basic usb device, it is totally OK to not understand any of this. That is how people learn by doing and asking 
