20090917 - Introduction to NACHOS NACHOS is a real...

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Introduction to NACHOS NACHOS is a real operating system that supports the execution of programs on a simulated computer. The NACHOS kernel is written in Java and it runs under a native JVM on the host processor/operating system. ( e.g. Intel x86/Windows). The NACHOS kernel is compiled with the standard JDK Java compiler, which produces code for the JVM. NACHOS kernel memory is managed by the JVM. Most of the programming you will do is for the NACHOS kernel.
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NACHOS user applications are written in C and they run on a simulated MIPS R2/3000. NACHOS applications are compiled with a cross-compiler running on Intel x86/Windows but producing code for MIPS/NACHOS. MIPS memory is managed by the NACHOS kernel (you have to write support for this).
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NACHOS Organization
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NOTES: NACHOS itself consists of a collection of Java classes. The NACHOS operating system is “booted” by starting the JVM and loading Nachos.class . NACHOS applications must be run using special command- line arguments to NACHOS: run -x halt NACHOS applications are in a special NACHOS executable format (“NOFF”) which is like historical versions of the traditional unix a.out format. It does not make any sense to ask the host OS to execute NACHOS applications directly – they must be executed by NACHOS.
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Processes vs. Threads The term process usually refers to a single thread of control that executes in its own private address space, separate from the address spaces of other processes. Processes are the unit of multiprogramming traditionally supported by older operating systems. Context switches between processes require changing the entire address space, and thus are fairly expensive. Communication between processes requires additional
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This note was uploaded on 12/19/2009 for the course CSE 306 taught by Professor Kifer,m during the Spring '08 term at SUNY Stony Brook.

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20090917 - Introduction to NACHOS NACHOS is a real...

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