The following schedule is tentative and subject to change without notice.

Credit: Most of slides for this lecture are based on materials provided by the authors of the textbook and references.

For project submission and automatic grading, we are running a dedicated server at https://sys.snu.ac.kr. If you want to access the sys server outside of the SNU campus, please send a request via a Google Form whose URL is posted in the eTL.

Project #5: FullFS: A File System with Full-Path Indexing

Full-path indexing is a file system technique where directories store the complete path and associated inode information for each file or subdirectory. The goal of this project is to explore the implementation of a full-path indexing mechanism in the xv6 file system, focusing on its impact on directory structure management and pathname resolution efficiency.

• Project specification available here
• Due date: 11:59PM, December 22 (Sunday).

Project #4: Xswap: Compressed Swap for xv6

The xv6 kernel currently lacks support for swapping. This project introduces Xswap, a compressed memory cache for swap pages inspired by Linux’s Zswap feature. By storing swap pages in a compressed format within RAM, Xswap reduces disk I/O and improves overall performance under memory pressure. The goal of this project is to understand the virtual memory subsystem in xv6 and explore the challenges and design considerations involved in adding swapping functionality.

• Project specification available here
• Due date: 11:59PM, November 24 (Sunday).

Project #3: SNULE: A Simplified Nerdy ULE Scheduler

Currently, the CPU scheduler of xv6 uses a simple round-robin policy. The goal of this project is to understand the scheduling subsystem of xv6 by implementing the simplified version of FreeBSD’s ULE scheduler.

• Project specification available here
• Due date: 11:59PM, October 27 (Sunday).

Project #2: System calls

System calls are interfaces that allow user applications to request various services from the operating system kernel. This project aims to explore and understand how system calls are implemented in the xv6 operating system.

• Project specification available here
• Due date: 11:59 PM, October 6 (Sunday).

Project #1: Hello world, xv6

xv6 is an instructional operating system developed by MIT based on Ken Thompson and Dennis Ritchie’s Unix version 6 (v6). In this course, we will use xv6-riscv, a version recently ported to a multi-core RISC-V machine. The goal of this project is to set up your development environment on Linux or macOS and familiarize yourself with our project submission server.

• Project specification available here
• Due date: 11:59 PM, September 19 (Thursday).

xv6 Resources

• xv6 source code: https://github.com/snu-csl/xv6-riscv-snu (our customized version)
• xv6: a simple, Unix-like teaching operating system (Rev. 4)
• The RISC-V Reader: An Open Architecture Atlas
• RISC-V Instruction Set Manual Volume I: Unprivileged Architecture, Version 20240411
• RISC-V Instruction Set Manual Volume II: Privileged Architecture, Version 20240411