News

• [Dec 21] Grades posted.
• [Dec 16] Exam 3 info
• [Dec 5] Filesystem note
• [Nov 25] Exam 2 scores posted. Solution and scoring/cutoffs
• [Nov 20] Project 5
• [Oct 11] Exam 2 info
• [Oct 11] Updated multi-threading note with awaits and readers-writers (sections 11 and 12)
• [Oct 24] Improving your 412 performance
• [Oct 22] Project 4 (new write up; just cosmetic changes)
• [Oct 20] Project 4 (old write up)
• [Oct 18] Exam 1 scores posted. Solution and scoring/cutoffs
• [Oct 11] Exam 1 info
• [Oct 11] Class notes on multi-threaded programs
• [Oct 4] Project 3.
• [Sep 27] topics (covered and soon to be covered).
• [Sep 24b] Project 2.
• [Sep 24a] Schedule for exams and remaining projects:
  • Project 2: due Mon Oct 5
  • Exam 1: Mon Oct 15 ??
  • Project 3: due Fri Oct 19
  • Project 4a: due Wed Oct 31
  • Project 4b: due Fri Nov 16
  • Exam 2: Mon Nov 19 ??
  • Project 5: ...
  • Project 6: ...
  • Last day of class: Dec 11
  • Final exam: Mon Dec 17 1:30pm-3:30pm
• [Sep 14] GeekOS overview (updated).
• [Sep 10] GeekOS overview (under construction).
• [Sep 07] Project 1 (due: Friday Sept 14 see Piazza).
• [Sep 01] Project 0 (due Monday Sept 10).
• [Aug 29] We will be using Piazza. Sign up with your name: https://piazza.com/umd/fall2012/cmsc412

Overview

This course is a hands-on introduction to operating systems, including topics in: multiprogramming, communication and synchronization, memory management, IO subsystems, and resource scheduling polices. The objective is an in-depth understanding of how an operating system manages resources in a computer and provides programmers with a machine and device independent interface. The classes emphasize concepts.

There is a significant programming project (GeekOS). You are provided with the source code (about 3000 lines of C and some assembly) of a "Unix-style" skeleton operating system for a PC-like x86 platform. You have to understand a large part of this code and augment it with various OS functionality: interprocess signals, semaphores, cpu scheduling, memory paging, file system, etc. The programming environment is Gnu/Linux. The x86 platform is simulated by QEMU. You can use the linuxlab cluster, but you will probably want to run the environment on your own machine. Overall it is very intensive and time consuming.

Topics covered (in order approximately):

• Introduction to operating systems
• Overview of GeekOS
• Processes/threads: implementation, protection, scheduling
• Concurrent processes: reasoning, synchronization, communication.
• Deadlocks: prevention, avoidance, detection.
• Memory management
• File systems: interface, implementation
• I/O systems (disks, etc.)
• Other topics (e.g, security, networking, etc.)

Required text:

Operating System Concepts, 6th edition or later, Siberschatz, Galvin and Gagne, Wiley.

• Note 1: Some Basic Concepts about Processes
• Note 2: Toy OS
• Note 3: Toy OS with Asynchronous IO
• Note 4: Basic Concepts about Concurrent Processes
• Note 5: N-Process Mutual Exclusion Problem
• Note 6: Peterson's Solution for 2-Process Mutual Exclusion
• Note 7: Bakery Algorithm
• Note 8: Low-level ready-modify-write atomicty
• Note 9: Semaphores
• Note 10x: Binary Semaphores
• Note 11: No Busy Waiting
• Note 12: Bounded-buffer Producer-Consumer Problem
• Note 13: Readers-Writers Problem
• Note 14: Dining Philosophers Problem
• Note 15: East-West Bridge Problem
• Solutions to selected problems in OSC text (ed 5).
• Note 16: Introduction to Queueing (ps, pdf)

Programming projects

• Project 0 (due Monday Sept 10).

Grading

• Midterm 1: approx 15% (Date: TBD)
• Midterm 2: approx 15% (Date: TBD)
• Final        : approx 25% (Mon Dec 17 1:30pm-3:30pm)
• Project: approx 45%
• Class participation: approx 5%

Missed exams or submission deadlines

• Each project has a regular deadline and one or two late deadlines, which will be fixed soon after the project is assigned. No submissions after the last late deadline.
• If you miss an exam or project deadline due to medical or family emergency, please see me. If it's due to illness, please bring documentation signed by a health care professional.
• If you miss a midterm exam, the weight of the exam will be moved to the next exam.

Regrades

Any regrade request (for exams, homeworks, projects) must be submitted within a week of the grade being posted.

Academic Integrity

Projects are to be done individually. Do not show others your source code. Do not look at another's source code. You can discuss your program with others. You can jointly examine the unmodified GeekOS distribution source code.

Academic dishonesty.