Nachos Overview 2011 级 OS 课程设计 2013 秋

to get your hands dirty Read and analyze Build observe

the only way to teach operating systems concepts and their design and implementation effectively is to have students read and experiment with an operating system at the source code level.

Nachos The Nachos operating system is a small working operating system on MIPS architecture written by Prof. Tom Anderson from the University of California at Berkeley and used widely for teaching operating systems throughout the world The only difference between Nachos and a ``real'' operating system is that Nachos runs as a single Unix process, whereas real operating systems run on bare machines.

How to study Our goal is to give you guidance not only to study the concepts in the text, but also to read and understand the source code of the Nachos operating system we use the Nachos source code to illustrate the concepts. This is probably the only way to enable you to have a sound grasp of the concepts described in the text.

How to study the first round of reading. As a matter of fact, you will need to go back and forth between the text and the relevant Nachos source code many times before you can really grasp the concepts in this module Understanding and experimenting

Contents Introduction Installation Nachos directory structure

1. Introduction Nachos has an excellent balance between simplicity and realism – Nachos is a UNIX process – Nachos was originally developed for use on DEC MIPS systems (DEC was acquired by Compaq years ago, which was acquired in turn by HP recently) and user programs are in binary format, making Nachos real enough avoiding the sense of a toy. side- by- side – The program nachos implements both the machine simulation and the operating system

1.1 The architecture of Nachos

1.2 MIPS simulator Timer Disk Network Console – a display and a keyboard MIPS instruction processor

1.3 MIPS/intel user- level code – Run at MIPS – gcc cross- compile Nachos – Run at intel

2 Installation 2.1 Cross compiler 2.2 Nachos

3. Nachos directory structure code – contains all source code and configuration files for Nachos – bin. COFF for unix; NOFF for Nachos – machine The machine simulation – threads Thread support main() routine of the nachos program, in main.cc the best place to start reading the Nachos code

3. Nachos directory structure cont. code – userprog the creation of address spaces loading of user (test) programs, and execution of test programs on the simulated machine – filesys The ”real” file system uses A“stub” file system – Network support for networking – test User test programs to run on the simulated machine

4 Assumption of UNIX skills basic UNIX commands and file systems make utility and Makefiles gdb debugger tool

5. What This Course Is About It concentrates on the concepts and techniques in design and implementation of operating systems This course covers the design and implementa- tion of three principle components of operating systems – Process Management – Memory Management – File Systems Management

6. Teaching Material Textbook – Operating System Concepts" Nachos Source Code – about 9,500 lines of C++ code with extensive comments Study book

Laboratoris Laboratory 1: Installation of Nachos System Laboratory 2: Makefiles of Nachos Laboratory 3: Synchronization Using Semaphores Laboratory 4:Nachos File system Laboratory 5: Extendable Files Laboratory 6: User Programs and System Calls Laboratory 7: Extension of AddrSpace Laboratory 8: System Calls Exec() and Exit()

Assignments Assignment 1: Overview and process Assignment 2: Synchronization and monitors Assignment 3: File System Interface and Implementation

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