For virtual memory to work a sophisticated

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Unformatted text preview: tual address space. execution of the program. In particular, each time we call a function, the stack grows. Each time we return from a function, it contracts. We will learn how the compiler uses the stack in Chapter 3. ¯ Kernel virtual memory. The kernel is the part of the operating system that is always resident in memory. The top 1/4 of the address space is reserved for the kernel. Application programs are not allowed to read or write the contents of this area or to directly call functions defined in the kernel code. For virtual memory to work, a sophisticated interaction is required between the hardware and the operating system software, including a hardware translation of every address generated by the processor. The basic idea is to store the contents of a process’s virtual memory on disk, and then use the main memory as a cache for the disk. Chapter 10 explains how this works and why it is so important to the operation of modern systems. 1.7.4 Files A Unix file is a sequence of bytes, nothing more and nothing less. Every I/O device, including di...
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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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