backboardd, or BackBoard, is a daemon introduced in iOS 6 to take some of the workload off of SpringBoard. Its chief purpose is to handle events from the hardware, such as touches, button presses, and accelerometer information. It communicates with SpringBoard through BackBoardServices.framework.
BackBoard also manages the launching, suspension, and termination of application processes.
Hardware Management
BackBoard is responsible for forwarding the following hardware events to the top application:
- Accelerometer input
- Hardware keyboard input
- Orientation events
- Proximity sensor events
- TV/Video out events
The above events are sent to the destination process via the GSEvent framework.
Going in the opposite direction, backboardd also allows processes (such as Preferences.app and SpringBoard) to change the brightness level.