A-level Computing 2009/CIE/Operating Systems

Basic process flow: __________________________________________________________________________________________________________ | | Yes | Yes | Yes V | | | Start - Fetch - Decode - Execute - Check for interrupt - No - Check for more instructions - No - Return to previous instruction? - No - End Operating system is made out of 4 components: User interface - provides an interface for the user to communicate with the hardware Kernel - translates the inputs from the U.I. in Machine Code for the hardware ( device drivers and utilities ) to understand Device drivers - The set of instructions that the hardware can understand ( a user manual of the device for the kernel , basically ) Utilities - Power management, Managing Fragmentation, System Security etc. The Scheduler The Scheduler is a part of the OS that manages how much time each process spends using the processor. References