News

• [May 13] Exam 3 info:
  • About 50% from material after exam 2 (ie, topics 7--9, projects 4--5).
  • sample exam problems
  • Topics 1--9 from topics in detail (updated May 13)
  • Projects 0--5
• [Apr 22] Exam 2 info:
  • About 50% short text answers and 50% analytical
  • sample exam problems
  • Topics 5, 6, and part of 7 (slides 1-25) from topics in detail
  • Topics 1-4: no questions directly on these, but you will need them as background
  • Projects 3, 4
• [Apr 19] Project 5 posted
• [Apr 14] Updated demand-paging section in os-memory-slides (same link as before).
• [Mar 30] Exam 1 scores posted. I'll give back exams and go over the exam and grading in class tomorrow.
  Cutoffs (if I had to give grades based only on this exam)
  ≥ 60 A-
  ≥ 50 B-
  ≥ 37 C-
  ≥ 30 D
  < 30 F
  I think it's unrealistic to expect to pass the class if you have an F here
• [Mar 29] Project 4a and Project 4b posted
• [Mar 11] Exam 1 info:
  • sample exam problems
  • Topics 1, 2, 3, 4 and part of 5 (slides 1-16) from topics in detail
• [Mar 8] Project 3 posted
• [Feb 27]
  Updated and shortened OS Process slides (same link as before).
  Added "Implementing Locks, Conditions, Semaphores" slides.
• [Feb 25] GeekOS overview updated. The filesystem sections are unchanged.
• [Feb 23] Project 2 posted
• [Feb 8] Project 1 posted
• [Feb 5] We are done with topic 1 in topics in detail. Please read the relevant text material.
• [Jan 30] Updated "GeekOS overview". Current: geekos-overview-s2015. Previous: geekos-overview-2013.
• [Jan 28] Schedule of projects and exams posted. Tell me soon if an exam date is problematic.
• [Jan 27] Project 0 posted
• [Jan 25c] There will be a discussion session on Monday Jan 26.
• [Jan 25b] VM link: http://www.cs.umd.edu/~hollings/cs412/s14/412studentVM.ova
• [Jan 25a] Piazza signup (with your name): https://piazza.com/umd/spring2015/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.

There is a significant and time-consuming 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 x86 platform is simulated by QEMU. The programming environment is Gnu/Linux.

• Download the Linux VM from http://www.cs.umd.edu/~hollings/cs412/s14/412studentVM.ova
• Download a virtualizer (e.g., VirtualBox, VMWare) to run the VM

Schedule

Schedule of projects (P0-P5) and exams (E1-E3)

Topics in general

• 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.)

Topics in detail

Notes/text

• Book 1: Operating System Concepts, 6th edition or later, Siberschatz, Galvin and Gagne, Wiley. (required)
  Gentle and fluffy ... No need for very recent version. Editions 6 and some later ones are inexpensive (perhaps free).
• Book 2: Operating Systems: Principles and Practice, Thomas Anderson, Michael Dahlin. (recommended)
  Concrete and detailed. Much more precise than book 1 but not as gentle. Recent book, so no inexpensive old editions.
• Course overview slides
• ToyOS slides
• GeekOS overview
• OS Process slides
• Implementing Locks, Conditions, Semaphores slides
• Memory management slides
• Filesystem slides
• Deadlocks slides
• Queueing slides
  • For more on queueing, see here (not required)
• On concurrent programming

Grading

• Your letter grade is based non-linearly on exams and projects
  • Exam 1: approx 15% (date: TBD)
  • Exam 2: approx 15% (date: TBD)
  • Exam 3: approx 20% (date: official final exam)
  • Projects: approx 50%
• "Approx" means +/− 5%
• You will get a letter grade (D, F, C-) for the projects and a letter grade (D, F, C-) for the exams.
• If you get D or F in either, then that is your course grade.
• If you get C- or higher in both, your course grade will be based on both and will be C- or higher.
• I'll consider class participation (by at most 4%) if you are close to a cutoff.

Missed exams and submissions

• 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 (barring medical/family emergency).
• 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 an exam, I'll give you a makeup or move its weight to a later exam (my choice).

Regrades

Any regrade request must be submitted within a week of the project grade being posted or the exam being returned.

Academic Integrity

Projects are to be done individually. Do not expose your source code to others. Do not leave it potentially accessible to others (e.g., unlocked unattended laptop). 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.

UMD Student Honor Council.