NachOS 4.0

Now Compatible with 64-bit Linux Machines

This is a modified version of NachOS (Original NachOS available at https://homes.cs.washington.edu/~tom/nachos/) which has undergone various patches to make it compatible with modern Linux machines.

The original readme file has been relocated to README.Original.md

In this project, only the Halt() system call from the original NachOS and our sample PrintInt() system call have been implemented. Attempting to use other unimplemented system calls will result in a core dump.

As of now, this project has been tested and confirmed to work on the latest LTS version of Ubuntu Linux (22.04)

Please note that the non-LTS versions of Ubuntu (or Debian-based) have not been tested but are expected to work. However, we do not provide support for non Ubuntu LTS versions.

Table of Contents

• Prerequisite
  • For 64-bit Ubuntu Linux
  • For 32-bit Ubuntu Linux
  • Download Project
  • Install Cross-Compiler for NachOS
• Building NachOS
• Testing NachOS
• Make Usage
• NachOS Usage
• Debug Flag
• Adding User Program
• References

Prerequisite

For 64-bit Ubuntu Linux

Enable i386 architecture first

$ sudo dpkg --add-architecture i386 

Preform system upgrade

$ sudo apt update; sudo apt dist-upgrade

Install the dependency (csh/git/compiler)

$ sudo apt install csh ed git build-essential gcc-multilib g++-multilib gdb gdb-multiarch

For 32-bit Ubuntu Linux

Preform system upgrade

$ sudo apt update; sudo apt dist-upgrade

Install the dependency (csh/git/compiler)

$ sudo apt install csh ed git build-essential gdb

Download Project

Clone the project repository

$ git clone https://github.com/wynn1212/NachOS

Install Cross-Compiler for NachOS

Navigate to the NachOS directory, then copy the cross-compiler to the system directory

$ cd NachOS
NachOS$ sudo cp -r usr /

Building NachOS

Navigate to the code directory in NachOS, then run make to build NachOS

NachOS$ cd code
NachOS/code$ make

Note 1: Whenever you make modifications to the source code, it is essential to rebuild the entire NachOS system.

Note 2: If your modifications are limited to the test directory, you can simply execute make within the test directory to build your program. However, if you have made changes to system calls or other core components, it is still necessary to rebuild the complete NachOS system.

Testing NachOS

After a successful build, you should find the nachos executable in the NachOS/code/userprog/ directory and your test1 program in the NachOS/code/test/ directory.

To run test1 in NachOS, execute the following command:

NachOS/code$ ./userprog/nachos -e ./test/test1

Please note that you should be inside the NachOS/code directory. Otherwise, you should specify the actual location accordingly.

If you see this output, it indicates that you have successfully run test1 in NachOS.

NachOS/code$ ./userprog/nachos -e ./test/test1
Total threads number is 1
Thread ./test/test1 is executing.
Print integer:9
Print integer:8
Print integer:7
Print integer:6
return value:0
No threads ready or runnable, and no pending interrupts.
Assuming the program completed.
Machine halting!

Ticks: total 200, idle 66, system 40, user 94
Disk I/O: reads 0, writes 0
Console I/O: reads 0, writes 0
Paging: faults 0
Network I/O: packets received 0, sent 0
NachOS/code$

Make Usage

See documents/Make_Usage.md

NachOS Usage

See documents/NachOS_Usage.md

Debug Flag

See documents/Debug_Flag.md

Adding User Program

See documents/Adding_User_Program.md

References

• https://homes.cs.washington.edu/~tom/nachos/ - Original NachOS 4.0 source code and documents.
• GitHub - connlabtw/NachOS2020 - This repository originated as a fork and includes the PrintInt() system call implementation.
• https://blog.csdn.net/Aloneingchild/article/details/115339992 - A guide that provides a solution for building NachOS on 64-bit Linux systems.
• GitHub - Yan-Hau/NachOS - Another solution for building NachOS on 64-bit Linux systems. This repository includes information about the required dependency packages for NachOS.
  • If you want to run NachOS on Docker or WSL2, you can follow the provided guide.
  • If you're interested in learning how to use gdb (GNU Debugger) with Visual Studio Code for NachOS development, there's also a guide available.
  • Please be aware that this repository uses NachOS 4.1, which has a different source code structure compared to our NachOS 4.0. Additionally, it does not have the PrintInt() system call implemented, which means you'll need to implement the PrintInt() system call yourself if you choose to use this version.