In computing, the ( ) is the central component of most computer operating system, it is a bridge between applicasions and actual data processing done at the hardware level. The ( )'s responsibilities include managing the system's resources(the communuication between hardware andn software components). Usually as basic component of an operating system, a ( ) can provide the lowest-level abstraction layer for the resources(especially processors and I/O devices) that application software must control to perform its function. It typically makes these facilities availavle to application processes throught inter-process communucation mechanisms and system calls.