Chapter Three- Operating System Structure

Operating-System Structures!
• Operating System Services!
• System Calls!
• System Programs!
• System Structure !
• Virtual Machines!
• System Design and Implementation!
• System Generation!

Operating System Services!
• Program execution – system capability to load a program into memory and to run it.!
• I/O operations – since user programs cannot execute I/O operations directly, the operating system must provide some means to perform I/O.!
• File-system manipulation – program capability to read, write, create, and delete files.!
• Communications – exchange of information between processes executing either on the same computer or on different systems tied together by a network. Implemented via shared memory or message passing.!
• Error detection – ensure correct computing by detecting errors inthe CPU and memory hardware, in I/O devices, or in user programs.!


Additional Operating System Functions!
Additional functions exist not for helping the user, but rather for ensuring efficient system operations.!
• Resource allocation – allocating resources to multiple users or multiple jobs running at the same time.!
• Accounting – keep track of and record which users use how much and what kinds of computer resources for account billing or for accumulating usage statistics.!
• Protection – ensuring that all access to system resources is controlled.!