Lecture: intro

Overview

• prereq: CSE 451 or equivalent
• grading
  • 30% participation + 30% assigments + 40% projects (in groups of 2–3)
  • no late days
• class structure
  • read systems papers: key ideas, limitations, etc.
  • describe your own ideas
  • engineering vs. research
• paper discussion lead
  • sign up for two slots before the end of this week
  • schedule a meeting with staff at least one week before your presentation
  • post paper questions to the discussion board
• non-lead
  • post your answers to questions to the discussion board 11pm before lecture
  • post additional questions you want to discuss

Today’s plan

• Perspectives on OS Foundations

A system is a set of interconnected components that has an expected behavior observed at the interface with its environment.

– Principles of Computer System Design, Saltzer & Kaashoek

• goals: correctness, performance
• how to cope with complexity
  • modularity, abstraction
  • challenges: unclear spec, cost
• example: the write(fd, buf, size) syscall
  • modularity: user / kernel
  • abstraction: file descriptor
  • what’s the expected behavior?
    • the x86_64 ABI?
    • does it guarantee the data will reach disk?
  • journaling-of-journal problem: LevelDB on ext4 on an SSD? what about a replciated key-value store?
• The case for application-specific operating systems