What is an operating system?

• e.g., macOS, Windows, Linux, FreeBSD, Android, iOS, etc.

What is an operating system?

• e.g., macOS, Windows, Linux, FreeBSD, Android, iOS, etc.
• What does an OS do for you?
  • Abstract the hardware for convenience and portability
  • Multiplex the hardware among multiple applications (or virtualization)
  • Isolate applications to contain bugs
  • Allow sharing among applications

View 1: layered organization

• User: applications (e.g., vi and gcc)
• Kernel: file system, process, etc. (← often considered as an OS)
• Hardware: CPU, mem, disk, etc.

→ OS is an Interface b/w two layers, user and hardware

View 2: consisting of core services

• Core/system services:
  • Processes (not CPU)
  • Virtual memory (not physical DRAM)
  • File and directory (not storage like HDD or SSD)
  • Many others: users, IPC, network, time, terminals, security, etc.

→ OS provides Abstraction to applications

Example: system calls

• Interface: applications talk to an OS via system calls
• Abstraction: process and file descriptor

  fd = open("out", 1);      // opening a file
  write(fd, "hello\n", 6);  // reading the file's content
  pid = fork();             // creating a new process

Why is designing OS challenging?

• Conflicting design goals and trade-offs:
  • Performant yet portable
  • Isolated yet sharable
  • Extensible yet secure
  • Compatible yet efficient

→ Open problems: sandboxing for security, scalability on manycore, etc.

Who should take CS3210?

• Anyone wants to work on the above problems
• Anyone cares about what’s going on under the hood
• Anyone has to build high-performance systems (e.g., Cloud, Trading)
• Anyone wants to build embedded/IoT firmware (e.g., Robot)
• Anyone needs to diagnose bugs or security problems

Also, you (have to) have lots of free time …

CS3210: Design Operating Systems

• Designing an Embedded Operating System with Rust
  • Embedded OS: 32-bit x86 → 64-bit AArch64 (ARMv8)
  • Real hardware: x86 laptop → Raspberry Pi 3
  • Modern language: asm/C → Rust!

→ Experimental course, lots of bumps expected :)

Cool kids speak Rust!

• Q. How many people heard about Rust?
• Q. How many people tried learning Rust?
• Q. How many people thought of learning Rust at some point?

→ Check out https://www.rust-lang.org/

Course goals and objectives

• Not just about OS, but more about “how-to” learn:
  1. Learn by coding
  2. Learn by guidance
  3. Learn from peers

→ So you can continue to learn OS even after graduation!

Prerequisite

• C programming (strict)
• CS 2200: Systems and Networks (strict)
• CS 2110: Computer Organization and Programming (recommended)
• CS 3220: Processor Design (recommended)

I’m doing a (free) operating system (just a hobby, won’t be big and professional like gnu) for 386(486) AT clones. – Linus Torvalds

General information

• Web: https://tc.gts3.org/cs3210/2020/spring
• Piazza: https://piazza.com/class/k4iwq4owaka7pc
• Text: freely available online
  • The Rust Book
  • Rust by Example
  • (optional) Operating Systems: Three Easy Pieces
  • (optional) Linux Kernel Development

General information

• Team: send us an email for an appointment (3210-staff@cc.gatech.edu)
• Office hours: will be announced on Thursday

Grading policy

• Preparation (10%)
• Quiz (30%: 10%/20%)
• Lab (40%)
• Final project (20%)
  • Proposal presentation (5%)
  • Demo & presentation (15%)
  • Write-up (5%)

Grading policy

• Negotiating your grade after Quiz 1 (Feb 25):
  • Based on what you’ve done until Quiz 1, we provide a tentative grade
  • You offer us what you will do to get whichever grade you want
  • We accept or offer an alternative path!

→ Our goal is to make sure you don’t give up, and actually sit and do the coding!

Class structure

• Schedule for Lab assignment/Lectures/Preparation

About preparation questions

• Submit your answers and questions (DUE: by 10pm the day before),

About quiz, project

• Two quiz (in-class, about lec/lab)
• About final project
  • Topics: https://tc.gts3.org/cs3210/2020/spring/proj.html
  • Mark the Team Proposal (Mar 05) and Demo Days (Apr 09/14)!

About lab assignments

• RustOS: a toy operating system written w/ Rust
  • Lab 0: Rustlings
  • Lab 1: Bootstrapping Raspberry Pi
  • Lab 2: Shell and Bootloader
  • Lab 3: FAT32 Filesystem
  • Lab 4: Multitasking and Locking
  • Lab 5: Scalable TCP/IP

About lab 0

• “Lab 0: Rustlings” is out (Due: Jan 20)
• Kicking-off on the Rust programming language

Class policy

• Late day
  • A week (i.e., 7 days) of a grace period (in total for all labs)
  • Don’t have to inform us (e.g., job interview, sick)
• No cheating
  • Cheating vs. collaboration
  • Write the name(s) of your sources/collaborators

See, https://tc.gts3.org/cs3210/2020/spring/info.html

Today’s agenda

• Hardware trends
• What challenges are in developing an operating system?
• Why a programming language matters?

Hardware trend: CPU

• by David A. Patterson and John L. Hennessy (2013)

Hardware trend: Memory

• by John C. McCallum (2015)

Comparing computer performance

• by Thomas E. Anderson (2015)

Hardware: IBM System/360 30/75 (1964)

• Ref. Computer History Museum
  • CPU: 0.034/1 MIPS, 64K/8M (8-bit), $133,000+/$2.2m+
  • Tape Operating System (TOS), Basic Operating System (BOS/360) (ASM)

Hardware: Raspberry Pi Zero (2015)

• Ref. Raspberry.org
  • CPU: 1k MIPS (1 Gz, Single-core), 512 MB (32-bit), $5
  • Linux (C)

Challenges in operating systems

OS (software) seamlessly adopts to slow/fast, small/large hardware!

• Portability
• Performance
• Reliability
• Usability
• Security

About “compatibility”

• https://lkml.org/lkml/2012/3/8/495

Seriously. Binary compatibility is so important that I do not want to have anything to do with kernel developers who don’t understand that importance. If you continue to pooh-pooh the issue, you only show yourself to be unreliable. Don’t do it. – Linus

Future operating systems (xkcd)

• Large scale: lots of cores, bigger memory, huge storage
• Small scale: dust?
• Heterogeneity

Programming languages for OS development

What language is used for all commodity OSes (e.g., Linux, Windows)?

• 1964: PL/I for Multics
• 1969: C for Unix
• 1995: javaOS by Sun
• 2014: Swift for macOS (in part)

Ref. Wikipedia

Why using C for OS development?

• Portability
• No runtime
• Direct hardware/memory access
• (decent) Usability

→ Why not A, B, and C (e.g., Python, JavaScript, C++, etc)?

Comparing system programming languages

Ref. A Case for Oxidation: The Rust Programming Language

Hello, Rust!

Hardware for CS3210: Raspberry Pi 3

• Raspberry Pi 3 Model B+ (e.g., Starter Kit from Amazon, $84.99)
• Online/offline shops from the official site

Other purchasing options

Next lecture

• Next: introducing Rust!
• Visit our course website: https://tc.gts3.org/cs3210/2020/spring
• Don’t forget to submit “preparation question” (DUE: 10pm, Jan 8)
• “Lab 0: Rustlings” is out (DUE: Jan 20 in 2 weeks!)
• Perpetration: Rpi 3 + sdcard + reader (in two weeks, from Lab 1)