Transcript CS 342302 Operating Systems

CS 342302 OPERATING
SYSTEMS
Nachos Project 1
Start-up and System call
MOTIVATION
System calls are the interfaces that user
programs can ask services from kernel.
 How to add a new system call is very essential.

OBJECTIVE
Be familiar with the Nachos environment.
 Design and implement new system calls in this
project.

PLATFORM
Use Linux on our server.
 You could also build up your Linux environment
by yourself.

LOGIN
Download pietty (http://ntu.csie.org/~piaip/pietty/)
 Server IP : 140.114.71.238 PORT : 35568


需更改
LOGIN
如出現以下畫面
 選 “是(Y)”

LOGIN

Both the account name and the default password
are “os”+your student number. (ex. os9862518)
After you login, you must change your password.
(use passwd command)
 $passwd

BASIC COMMAND

NOTE : Some basic commands you have to know:
for example :
$cd <directory> : enter directory
$cd ..
: go back to upper directory
$cd ~
: enter home directory
$ctrl + c
: process termination
good place :
鳥哥的 Linux 私房菜 (http://linux.vbird.org/)
COMPLETE YOUR NACHOS
ENVIRONMENT
Enter your home directory
$ cd ~
 We have already prepared for you


nachos-java.tar.gz , nachos-java.tar.gz
Decompress it!
$ tar zxvf nachos-java.tar.gz
$ tar zxvf mips-x86.linux-xgcc.tgz
 Enter the nachos/test directory and execute make.
If there is no errors, your MIPS cross compiler
environment is set correctly.
$ cd nachos/test
$ make

MAKE RESULT

Note: If there are errors when you make, contact TA
please. Otherwise, you couldn’t complete this project
EXECUTE NACHOS

Go back and enter the proj1 directory and
execute make. It will create the directory named
nachos. Finally, execute nachos to run Nachos,
you will see some lines of messages when
running.
$ cd ..
$ cd proj1
$ make
$ nachos
RUNNING RESULT

If there is no error so far, your Nachos environment
is set successfully.
HOW TO MODIFY


Use vim on the server (suggested)
Reference : http://www.study-area.org/tips/vim/
http://linux.vbird.org/linux_basic/0310vi.php
Or you can use the FTP software (ex. FileZilla)
with SSH (port:22) to download and upload the
file which have to be modify, then you can use
your own editor in your operating system.
BASIC REQUIREMENT
IMPLEMENT & ADD THE FOLLOWING
SYSTEM CALL:
int add(int op1, int op2);
int pow(int op1, int op2);
void print(char *msg);
void print2(char *msg, int value);
You only need to parse the parameter %d.
void exit(int status);
In order to terminate user programs properly.
RELATED CODE FOR USER
PROCESSES
~/nachos/test/start.S
Startup assembly code for every user program of
Nachos.
 ~/nachos/test/syscall.h
Definitions of the system call prototypes
 ~/nachos/userprog/UserProcess.java
Encapsulates the state of a user process,
including the handler for system calls and other
exceptions.

ADD YOUR SYSTEM CAL

Declare a new system call in test/syscall.h
- Define a new system call ID
E.g., #define syscallAdd 13
- Declare the interface for Nachos system calls, which will
be called by the user program.
E.g., int add(int op1, int op2);

Add the low level operation to support the new
declared system call in test/start.S
E.g., SYSCALLSTUB(add, syscallAdd)
ADD YOUR SYSTEM CALL

handleSyscall in userprog/UserProcess.java
1. Define system call ID which you’ve defined in UserProcess.java
private static final int
syscallHalt = 0,
…..
2. Write your system call in the switch case
public int handleSyscall (int syscall, int a0, int a1, int a2, int a3)
{
switch (syscall) {
case syscallAdd:
return a0+a1;
…..
ADD YOUR PROGRAM

You have to run the following test program on
your Nachos.
ADD YOUR PROGRAM(CONT.)
If you call the test file “proj1.c”.
 First, put the file under /test, and modify the file
“Makefile”.

TARGETS = halt sh matmult sort echo cat cp mv rm #chat chatserver

TARGETS = halt sh matmult sort echo cat cp mv rm proj1 #chat chatserver

then “make” again under the /test directory.

If appear “make: Nothing to be done for `all'.”
$ make clean
 $ make

RUN YOUR PROGRAM
In file ~/nachos/proj2
 Then modify the line 12 of /proj2/nachos.conf

Kernel.shellProgram = halt.coff #sh.coff

Kernel.shellProgram = proj1.coff #sh.coff
“make” under /proj2.
 Enter “nachos” to run it.

RESULT
HINT

In system call “print” and “print2” may use the
functions below:
readVirtualMemoryString();
System.out.println();
try to know how to use it
SUBMISSION & GRADING POLICY
Code correctness 65%
 Every system call is 13%
 Readability 5%
 Report 30%
 Bonus 10%

BONUS

Anything different from Basic Requirement

Build your own nachos' environment
For example :
 Using Vmware, install Ubuntu, nachos, mips …etc.


Another system call
For example :
 Create, open, write, read …etc.

REPORT REQUIREMENT

Free but basically
 What
problem have you met and how to solve it
 What
have you learned from this project
 Your
bonus part (if have, Explain it in detail)
 報告越詳細分數越高
DEADLINE

2009 / 10 / 21 ( 23:59 pm)
OFFICE HOUR

:
週一 (Mon) : 7:00pm~10:00pm 綜二 751
REFERENCES

鳥哥的 Linux 私房菜

Linux 基本操作