NACHOS Source Code

Most of what you learn in this class you will learn by reading and modifying NACHOS source code. You need to become very familiar with the structure of that code, as early as possible. Here are some important points.

• The Makefiles are designed to help organize the projects. They work with gmake, rather than make. Use these Makefiles all the time: don't even think of issuing your own compiler commands.
• In order for the Makefiles to work properly, you need to use exactly the directory structure in which the source is now stored. You may also get at the source files directly through UNIX on the CS system, outside of any WWW browser, at the path /condor/cscfclt/jmontgo2/cs546/nachos-3.4.tar.gz/code.
• The code directories are organized, not according to the structure of the operating system, but according to the projects. Since these projects correspond fairly well to natural modules of the OS, that's not too bad for readability. But, some of the basic files are in the threads directory, not because they deal especially with threads/processes, but because the first project is concerned with threads.
• To complete your project work, you are allowed to change OS code, but not MIPS simulator code. All of the latter is in the directory code/machine. Do not change any file in code/machine. code/threads/switch.s and code/threads/swtch.s contain machine-dependent code for context-switching. For your own peace of mind, don't change these either.

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