CS 213: Introduction to Computer SystemsRandal E. Bryant(*) and David R. O’Hallaron(**)(*) School of Computer Science(**) School of Computer Science and Dept of Electrical and Computer EngineeringCarnegie Mellon UniversityFall 20001 OrganizationInstructors:Randal E. Bryant David R. O’HallaronWeH 4220 WeH 8125x8-8821 [email protected] [email protected] 10:00–11:00am Tue 10:30–11:30amTAs:Jason Crawford Blake Scholl Bianca Schroeder Tiankai TuWean Cluster Wean Cluster WeH 5123 WeH 5119x8-5728 [email protected] [email protected] [email protected] [email protected] 3:30–4:30 Wed 4:30–5:30 Tue 1:30–2:30 Tue 4:00–5:00Class Assistant:Rosemary BattenfelderWeH [email protected]:Tue Thu 9:00–10:20, Wean Hall 75001Recitations:A Mon 10:30–11:20 OSC (Old Student Center) 200 SchollB Mon 11:30–12:20 OSC (Old Student Center) 200 TuC Mon 12:30–1:20 OSC (Old Student Center) 200 CrawfordD Mon 1:30–2:20 OSC (Old Student Center) 200 SchroederE Mon 2:30–3:20 OSC (Old Student Center) 200 SchroederWeb page: www.cs.cmu.edu/afs/cs/academic/class/15213-f00/www/Newsgroup: cmu.cs.class.cs2132 ObjectivesOur aim in CS 213 is to help you becomea betterprogrammer by teaching you the basic concepts underlyingall computer systems. We want you to learn what really happens when your programs run, so that whenthings go wrong (as they always do) you will have the intellectual tools to solve the problem.Why do you need to understand computer systems if you do all of your programming in high level lan-guages? In most of computer science, we’re pushed to make abstractions and stay within their frameworks.But, any abstraction ignores effects that can become critical. As an analogy, Newtonian mechanics ignoresrelativisticeffects. The Newtonian abstraction is completely appropriate for bodies moving at less than 0.1c,but higher speeds require working at a greater level of detail.Oversimplifying matters somewhat, our 21sequence works as follows: 211 is based on a simplified modelof program execution. 212 builds further layers of abstraction. 213 introduces greater detail about systembehavior and operation. This greater detail is needed for optimizing program performance, for workingwithin the finite memory and word size constraints of computers, and for systems-level programming.The following “realities” are some of the major areas where the abstractions we teach in 211/212 breakdown:1. Int’s are not integers, Float’s are not reals. Our finite representations of numbers have significantlimitations, and because of these limitations we sometimes have to think in terms of bit-level repre-sentations.2. You’ve got to knowassembly language. Evenif you never write programsin assembly, The behavior ofa program cannot be understood sometimes purely based on the abstraction of a high-level language.Further, understanding the effects of bugs requires familiarity with the machine-level model.3. Memory matters. Computer memory is not unbounded. It must be allocated and managed. Memoryreferencing errors are especially pernicious. An erroneous updating of one object can cause a changein some logically unrelated object. Also, the combination of caching and virtual memory provides thefunctionality of a uniform unbounded address space, but not the performance.4. There is more to performance than asymptotic complexity. Constant factors also matter. There aresystematic ways to evaluate and improve program performance25. Computers do more than execute instructions. They also need to get data in and out and they interactwith other systems over networks.By the end of the course you will understand these “realities” in some detail. As a result, you will beprepared to take any of the upper level systems classes at Carnegie Mellon. Even more important, you willhave learned skills and knowledge that will help you throughout your career.3 TextbookCS 213 is a unique course for which no complete textbook exists. In fact, your instructors are currentlytrying their best to write a textbook based on this course. You’ll be getting previews, in the form of classnotes. We’ll hand out the notes to you as we write them up. We’d really appreciate your comments andcriticisms.In addition, we require you to have a reference book on the C programming language:Brian W. Kernighan and Dennis M. Ritchie, The C Programming Language, Second Edition,Prentice Hall, 1988.This the classic K & R book, the standard against which all reference manuals are compared. Although itonly provides partial coverage of the course material, it is an essential part of every computer scientist’slibrary.4 Course OrganizationYour participation in the course will involve five forms of activity:1. Attending the lectures.2. Participating in the recitations.3. Homework and laboratory assignments.4. Reading the text and supplementary handouts.5. ExamsAttendance will not be taken at the lectures or recitation sections. You will be considered responsible forall material presented at the lectures and recitations. Lectures will cover higher-level concepts. Recitationswill be more applied, covering important “how-to’s”, especially in using tools that will help you do the labs.In addition, the recitations will help clarify lecture topics and describe exam coverage.There will be two types of assignments in this class. Lab assignments will be multi-week efforts (in groupsof up to 2) providing in-depth understanding of some aspect of computer systems. Labs will involve some3combination of C and assembly programming, and some will involveperformance measurements. Labs willalways be handed out in class on Thursday and due a couple of weeks later on a Wednesday.Homework assignments will be 1-week efforts (that you work on individually) that involve solving a seriesof smaller problems. The solution to many of these will involve writing small C programs. Homeworks aredesigned to be drills to help you get practice for exam problems. Homeworks will always be handed out atclass on Tuesday and due the following Monday.5 Getting helpFor urgent communication with the teaching staff, it is best to send electronic mail (preferred) or to phone.If you want to talk to a staff member in person, remember that our posted office hours are merely timeswhen we guarantee that we will be in our offices. You are always welcome to visit us outside of office hoursif you need help or want to talk about the course. However, we
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