Jerry S Rawls Hall 1086
office hours: MW 10:45-11:45am and by appointment (LWSN 1211)
Vineeth Thomas Alex
email@example.com, M 1-3pm (HAAS G50, 494-5946)
firstname.lastname@example.org, Tue 1:30-3:30pm (HAAS 254)
email@example.com, Thu 11-1pm (HAAS 256, 494-7837)
PSOs: (HAAS 257)
T 3:30-5:20pm (Rajas)
W 11:30-1:20pm (Rajas)
W 1:30-3:20pm (Raine)
W 3:30-5:20pm (Raine)
F 11:30-1:20pm (Vineeth)
F 1:30-3:20pm (Vineeth)
Operating System Design – The Xinu Approach, Douglas Comer, latest edition (required)
Operating Systems Concepts by Silberschatz, Galvin and Gagne; latest edition (recommended)
- Lab6 has been graded. Please follow the same procedure as before to access your score (lab6.rpt) and follow up.
The final exam is scheduled on May 2, 2017, 8-10am; STEW 183, closed book/note.
Exam duration is 1 hour.
The scope is comprehensive, however, prioritize material covered after
the second midterm.
Sample exam and solution.
- Lab5 has been graded. Please follow the same procedure as before to access your score (lab5.rpt) and follow up.
- Everyone will receive one extra late day to use as they see fit. This is equivalent to having a total of four late days. Intermittent system availability that affected CS on 4/4/2017 is not a valid reason for extending deadlines.
- Midterm 2 scores have been posted. Please follow the same procedure as before to access your score (mid2.rpt). Please pick up the midterms during my office hours.
- Lab4 has been graded. Please follow the same procedure as before to access your score (lab4.rpt) and follow up.
- Midterm 2 is scheduled on Mar. 27, 2017; in-class, closed book/note. The scope is comprehensive but focus on the material following the first midterm.
- Midterm 1 scores have been posted. Please follow the same procedure as the labs to access your score (mid1.rpt). Please pick up the midterms during my office hours.
- Lab3 has been graded. Please follow the same procedure as before to access your score (lab3.rpt) and follow up. The midterm 1 score will be posted on Wednesday.
- Lab2 has been graded. Please follow the same procedure as lab1 to access your score (lab2.rpt) and follow up.
Midterm 1 is scheduled on Feb. 24, 2017; in-class, closed book/note.
The scope includes material covered until Feb. 22, 2017.
Sample exam and solution.
Lab1 has been graded. The scores have been posted at
in file lab1.rpt where username is your login name. lab1.rpt is a plain ASCII text file. As noted in class, outside of the TAs and the instructor, only the person with the specified username can read the files in the directory. If you have any questions, please send an email to rkarandi, vthomasa, yeh10 (to all three).
- No PSOs in weeks 1 and 2 of class. Although not required, it is strongly recommended that students attend the PSOs where lab assignments are discussed and TA assistance is provided.
- Lab6 (html)
- Lab5 (html)
- Lab4 (html)
- Lab3 (html)
- Lab2 (html)
- Lab1 (html)
- TA Notes (html)
- XINU set-up: how to configure, compile, load and run XINU (html)
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
- Systems programming and architecture review, CPU instruction set, registers, RAM memory, programs, compilers, assembly and machine code
- Programs, functions, and processes
- Memory layout produced by C compilers, run-time stack and CDECL caller/callee convention (pdf)
- Memory layout of XINU and implications
- Isolation/protection: motivation and general architecture (hardware and software support), x86 specific implementation features
- Upper half and lower half organization of modern kernels, the kernel viewed as a reactive system comprised of function call code/libraries
- Processes and threads, invoking the scheduler from upper and lower halves, role of context switching and its mechanics in x86
- Time-share (TS) process scheduling: fairness, CPU- versus I/O-bound process classification
- Fair scheduling, implementation issues, and scheduling overhead
- Solaris UNIX Dispatch Table example: TS [dispadmin -c TS -g]
- Multi-level feedback queue and constant scheduling overhead
- Hardware/software support for process synchronization: issues, solutions, their pros/cons
- Meaning of blocking/non-blocking and synchronous/asynchronous IPC system calls (extends to general I/O system calls)
- Deadlock detection/prevention, overhead and kernel role
- Why kernel mechanisms for IPC extend to device I/O
- Basic memory management without special hardware support, external and internal fragmentation
- Conceptual solution to external fragmentation, why hardware support is required, three main benefits enabled by virtual memory support
- Components of modern memory management hardware support, memory hierarchy, caching, locality of reference and performance
- Boundary of virtual vs. physical addressing in memory hierarchy, trade-offs between hardware and kernel management of page faults and TLB misses
- Virtual memory and increase of context switch overhead
- Page replacement policies: optimal (offline Belady), LRU, global clock, and their relationship
- Motivation for multi-level page tables and memory savings: few elephants | many mice
- Paging and virtual to physical address translation: multilevel (e.g., 2-level) page tables to reduce page table size
- Memory thrashing: what it is, symptoms (page fault rate, CPU utilization), and solutions
- Linux example (pdf)
- Organization of lower half into top and bottom halves: motivation and their roles
- Two approaches for implementing the bottom half and their pros/cons
- Role of DMA (e.g., isochronous video streaming) and its integration in the lower half
- Three types of hardware clocks and their function
- Tickful vs. tickless kernels, their pros/cons
- Real-world file sizes (mice and elephants) and its impact on file system design
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:
|Midterms||30% (15% + 15%)|
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 firstname.lastname@example.org.
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 points 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 5% 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.