And the code and data of the program appear to be the

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Unformatted text preview: between Unix version are gradually disappearing. End Aside. 1.7. THE OPERATING SYSTEM MANAGES THE HARDWARE 13 1.7.1 Processes When a program such as hello runs on a modern system, the operating system provides the illusion that the program is the only one running on the system. The program appears to have exclusive use of both the processor, main memory, and I/O devices. The processor appears to execute the instructions in the program, one after the other, without interruption. And the code and data of the program appear to be the only objects in the system’s memory. These illusions are provided by the notion of a process, one of the most important and successful ideas in computer science. A process is the operating system’s abstraction for a running program. Multiple processes can run concurrently on the same system, and each process appears to have exclusive use of the hardware. By concurrently, we mean that the instructions of one process are interleaved with the instructions of another process. The operating system performs this interleaving with a mechanism known as context switching. The operating system keeps track of all the state information that the process needs in order to...
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This note was uploaded on 09/02/2010 for the course ELECTRICAL 360 taught by Professor Schultz during the Spring '10 term at BYU.

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