office hours: MW 9:30-10:30am and by appointment (LWSN 1211)
email@example.com, M 11-noon, T 3:30-4:30pm (LWSN B116)
firstname.lastname@example.org, W 10:30-11:30am, R 12:30-1:20pm (LWSN B116)
email@example.com, MF 2-3pm (LWSN B116)
firstname.lastname@example.org, WF 9:30-10:30am (HAAS G056)
PSOs: (HAAS 257)
F 11:30-1:20pm, 3:30-5:20pm
Operating System Design – The Xinu Approach, Douglas Comer, latest edition (required)
Operating Systems Concepts by Silberschatz, Galvin and Gagne; latest edition (recommended)
The final is scheduled on Dec. 18 (Fri), 2015: 8-10am, MTHW 210,
closed note/book. Scope: Comprehensive but focus on the material after
Sample exams: 2014 spring (sol) | 2013 spring (sol).
- lab4 has been graded. Please follow the same procedure as before to access your scores.
- lab3 has been graded. Please follow the same procedure as before to access your scores.
- The midterm has been graded. Please use the same method as lab scores to access mid.rpt. A copy of the midterm and solution. The solutions are expanded for clarity. Your answers can be more compact while receiving full credit.
- lab2 has been graded. Please follow the same procedure as before.
- lab1 has been graded. Follow the same procedure as in lab0 to access the scores (lab1.rpt). If you have any questions, please send an email to all four TAs.
The midterm is scheduled on Oct. 19 (Mon), 2015: in-class,
Sample exams: 2014 spring (sol) | 2013 spring (sol).
- lab0/hw0 has been graded. Please follow instructions in the TA notes to access the scores. If you have any questions, please send an email to all four TAs.
- Please consult the TA notes for further instructions and comments on the labs.
- No PSOs in week 1 of class. Although not required, it is strongly recommended that students attend the PSOs where lab assignments are discussed and TA assistance is provided.
Please follow instructions given in class for accessing lecture slides. The topics listed below include material not covered in the pdf lecture slides. They should be referenced from class notes.
- What is CS 354 about? (pdf)
- Operating system concepts and background (pp. 1-66, 91-123 from lecture slides)
- Systems programming and architecture review, CPU instruction set, registers, RAM memory, programs, compilers, assembly and machine code
- Memory layout produced by C compilers, run-time stack and CDECL caller/callee convention
- Programs, functions, and processes
- System calls: user mode/kernel mode, user space/kernel space
- Evolution of early computing systems and their operating systems: need for fault-tolerance/reliability to achieve high CPU utilization
- Isolation/protection: hardware support (privileged/non-privileged instructions, kernel/user mode, memory protection), software support (per-process kernel stack)
- x86-specific implementation of isolation/protection using protected mode: ring 0-3, segments and descriptor privilege levels (DPLs), CPL, IOPL, system call trap (e.g., int 0x80)
- Kernel configuration in Linux/UNIX/Windows vs. XINU: no isolation/protection; although XINU runs in protected mode, x86 hardware support for isolation/protection is not utilized
- How kernel scheduler (e.g., resched() in XINU) is invoked: top-down -- blocking system calls handled by upper half of kernel, bottom up -- interrupts handled by lower half kernel
- Time-share (TS) process scheduling: fairness, CPU- vs. I/O-bound process classification
- Solaris UNIX dispatch table example: TS [dispadmin -c TS -g]
- Constant overhead scheduling (O(1) time complexity) using a multilevel feedback queue
- Asynchronous IPC/IO with callback function, implementation issues to preserve isolation/protection
- External and internal fragmentation, indirection as a solution for handling external fragmentation
- Hardware support for virtual memory management: virtual addresses, locality of reference, caching (L1, TLB, L2, RAM, disk, SSD)
- Cache (L1, L2, TLB, RAM) misses: boundary of kernel vs. hardware responbility
- Virtual memory and increase of context switch overhead
- Paging and virtual to physical address translation: multilevel (e.g., 2-level) page tables
- Page replacement policies: optimal (offline Belady), LRU, global clock, and their relationship
- Memory thrashing: what is it, symptoms, and solutions
- Linux example (pdf)
- Kernel architecture: upper half and lower half, shared kernel buffer and input/output synchronization
- Lower half architecture: top half and bottom half design, trade-offs
- Necessity of DMA support for multimedia streaming
- Kernel, interrupt and DMA coordination
- Webcam video streaming implementation in Linux/Windows (pdf)
- Three types of hardware clocks based on function and features: system timer, high resolution counter, time of day clock
CS 250, 251, 252. Ability to understand and write complex programs in C. Familiarity with system development tools.
The grade will be determined by a midterm, final, and lab assignments. Their relative weights are:
Labs and Policies:
We will use the XINU operating system for the lab assignments. The XINU lab is located in the HAAS Building Room 257. The lab houses dedicated backend machines used for implementation, testing, and performance evaluation. They include Intel x86-compatible Galileo boards equipped with Quark X1000 processors and Linksys E2100L boxes. We will use x86 backends and frontends as our implementation platform.
Getting your CS account.
Students registered in the course should have an account automatically set up. Please check by going to HAAS 257 and logging in to one of the frontend machines (Linux PCs). If you have registered up but don't have an account, please contact email@example.com.
To help manage unexpected scheduling demands, you are given a budget of 3 late days in total that may be used for late submissions of lab/homework assignments. For example, you may submit 1 day late on three lab assignments, or 3 days late on one lab assignment. Any combination is valid as long as the total days delayed does not exceed 3. There will be a total of 6 lab assignments. Late days not utilized at the end of the semester will be converted to 25 bonus point each (maximum of 75).Due to the low-level systems nature of the lab assignments, coding and evaluating parts of an operating system running on hardware is time intensive. To encourage proactive handling of assignments, all submissions turned in 2 days prior to its deadline will be given a 10% bonus credit (as a fraction of the points received).
We wish to foster an open and collegial class environment. At the same time, we are vigorously opposed to academic dishonesty because it seriously detracts from the education of honest students. Because of this, we have the following standard policy on academic honesty, consistent with Purdue University's official policy.
It is permissible to discuss a general method of solution with other students, or to make use of reference materials in the library or online. If you do this, you will be expected to clearly disclose with whom you discussed the method of solution, or to cite the references used. Failure to do so will be considered cheating or plagiarism. The use of "method of solution" means a general discussion of technique or algorithm, such as one would reasonably expect to occur standing in front of a whiteboard, and precludes the detailed discussion of code. Specifically, looking at another student's code on his/her computer monitor is NOT allowed.
Unless otherwise explicitly specified, all code that is submitted is to be entirely each student’s own work. Using any code or copying any assignment from others is strictly prohibited without advance prior permission from the instructor. This includes the use of code others have submitted in the past.
All students work is their own. Students who do share their work with others are as responsible for academic dishonesty as the student receiving the material. Students are not to show work to other students, in the class or not. Students are responsible for the security of their work and should ensure that printed copies are not left in accessible places, and that file/directory permissions are set to be unreadable to others (e.g. use "chmod -R 700 *" from your home directory). If you need assistance protecting your work, please contact the TAs or the instructor.
Students who encourage others to cheat or plagiarize, or students who are aware of plagiarism or cheating and do not report it are also participating in academically dishonest behavior.
Be aware that we will use a software tool called MOSS to check for copying among submitted assignments. Additionally, the instructor and TA will be inspecting all submitted material to ensure honesty.
Any case of academic dishonesty will be dealt with by a severe grade penalty in the overall class grade and referral to the office of the Dean of Students.
In the event of a major campus emergency, course requirements, deadlines, and grading percentages are subject to changes that may be necessitated by a revised semester calendar. If such unusual circumstances arise, students may determine any such changes by contacting their instructors via email or phone, and checking the course web page for updates.
Emergencies and campus closings will be announced on local media and on the main Purdue University WWW site http://www.purdue.edu. Individuals may subscribe to an SMS text announcement service. Other details are on the Purdue emergency preparedness site.
This is an undergraduate introductory course to operating systems that investigates how modern operating systems are architected and implemented. Extensive implementation experience is gained by coding, testing, and benchmarking key components of the XINU operating system on dedicated backend hardware. Our main implementation platform will be x86-compatible backend machines and Intel x86 frontend PCs where code is developed. Most coding is done in C, with some hardware dependent components utilizing assembly language.
The topics covered in the course include: evolution of computing systems and their operating systems, process management, inter-process communication, memory manangement, virtual memory, I/O subsystems and device management, file systems, virtualization and security, and mobile operating systems. In addition to implementing key OS features in XINU, we will examine case studies in Linux, UNIX (Solaris and BSD), and Windows that differ from XINU and each other in significant ways. One important example is how I/O subsystems are architected to handle a range of heterogenous devices and their interrupts, including high-speed USB and wired/wireless network interfaces, that characterize many of today's computing systems. Kernel dependence on changing hardware features and support is an important theme throughout the course that will help familiarize with recent developments such as non-traditional file systems for flash memory prevalent in mobile systems. We will touch upon mobile OS (e.g., iOS, Android) with emphasis on differences with desktop/server operating systems.