Introduction to Computer Science GRE
Presented by Petar Petrov
pip010@gmail.com
GRE Computer Science Subject
www.ets.org To help admission committees and faculty to distinguish among prospective graduate students.
Employed mainly in North America, US and Canada.
Presentation Outline
• • • • • • • • • Brief overview of CS GRE test When and how to register How important is the CS subject test Scoring on the test Content by subject field Detailed content Preparation about taking the test Test taking strategies Sample test questions
Brief Overview
• • • • A paper based test Consisting of about 70 multiple-choice questions You will have 170 minutes total. Cover most of a decent CS Undergraduate Program curriculum • Questions are based on diagrams, graphs, and program fragments. • Distribution of questions is according to a content categories. See content outline following.
When and How to register
• • Registration fee 150$ The test is offered three times a year
ETS Regular Registration September 30 Approx. Score Report Mailing Dates December 22, 2005
GRE® Subject Test Dates November 12, 2005
December 10, 2005
April 1, 2006
October 28
February 17
January 13, 2006
May 5, 2006
• •
There are two test centers in Bulgaria
– – Sofia : SS Cyril & Methodius Int code:10655 Blagoevgrad: AUBG code:10051
You can register online www.ets.org using Credit Card or in cash at a test center.
How important is CS GRE
• Few if any CS department will require you to submit subject scores • In case of PhD degree you are expected to reach the 90% percentile boundary • Consider any alternative,
e.g. Mathematics, Physics subject tests, scale better and might have better impact.
• Contact each institution of interest and find out what impact the CS GRE will have on your application.
Scoring
The score is calculated based on the following formula:
•Then you have a Scaled Score based on the final number of correct answers •Involving a scaling table (see bulletin for more information) . •Also slight difference in question difficulty and questions count. (In recent years the number is fixed to 70) •Further you might have a number of experimental questions not included in the final scaled score, usually 3 to 5 ones.
Content by subject fields
I. SOFTWARE SYSTEMS AND METHODOLOGY 40% II. COMPUTER ORGANIZATION AND ARCHITECTURE15%
III. THEORY AND MATHEMATICAL BACKGROUND 40%
IV. OTHER TOPICS 5%
SOFTWARE SYSTEMS AND METHODOLOGY 40%
– Data organization (data types, data structures, file organization) – Program control (iteration and recursion, functions, synchronization) – Programming languages and notation (scope, binding, parameter passing) – Software Engineering (compilers and interpreters, OS fundamentals, networking, distributed systems)
COMPUTER ORGANIZATION AND ARCHITECTURE15%
– Digital Logic design (digital circuit, functional properties) – Processors and control units (instruction sets, registers, data paths) – Memories and their hierarchies (speed, capacity, cost, cache, secondary storage) – Networking and Communication (bus, switch, protocols, I/O, synchronization) – High-performance architectures (pipelining, parallel programming, distributed computing)
THEORY AND MATHEMATICAL BACKGROUND - 40%
– Automata and language theory (finite automata, parsers, decidability, formal languages) – Algorithms and complexity (asymptotic analysis, complexity, NP-completeness, design) – Discrete structures (mathematical logic, combinatorics and probability, counting, graph theory, recurrence, number theory)
OTHER TOPICS 5%
– Topics including modeling and simulation, information retrieval, artificial intelligence, computer graphics, data communications, databases, web programming, logic programming.
Preparation Books
• There are two official CS GRE books
by Benjamin Wells ISBN: 087891434X
by Jack Rudman ISBN: 0837352215
• Outdated and not comprehensive. • In 2003 ETS changed the entire question pool.
Best sources of preparation
• Internet places of interest, forums and discussion groups might prove very useful. Study Guides are even better sources.
http://www.ets.org/Media/Tests/GRE/pdf/CompSci.pdf http://www.urch.com/forums/gre-computer-science/
http://www.hunterthinks.com/studyguide/
http://www.geocities.com/titaniumbits http://groups.yahoo.com/group/grecs/
• Make use of any lecture notes, tests, books for all the COS classes you have passed at AUBG.
Test taking strategies
• Do not target every question. Each one is of equal value. • Timing is a key to high scoring. • Get familiar with the notation used in the test.
(both sample and real tests have it in the fist pages)
• Do not leave the last minutes for recording you answers. • Read questions carefully. If you do not understand the topic no point in guessing. • You should consider a balance between questions to skip and questions to guess.
SAMPLE QUESTIONS
A certain architecture supports indirect, direct, and register addressing modes for use in identifying operands for arithmetic instructions. Which of the following cannot be achieved with a single instruction? A. Specifying a register number in the instruction such that the register contains the value of an operand that will be used by the operation. B. Specifying a register number in the instruction such that the register will serve as the destination for the operation’s output. C. Specifying an operand value in the instruction such that the value will be used by the operation. D. Specifying a memory location in the instruction such that the memory location contains the value of an operand that will be used by the operation. E. Specifying a memory location in the instruction such that the value at that location specifies yet another memory location which in turn contains the value of an operand that will be used by the instruction.
SAMPLE QUESTIONS
The designers of a cache system need to reduce the number of cache misses that occur in a certain group of programs. Which of the following statements is/are true? I. If compulsory misses are most common, then the designers should consider increasing the cache line size to take better advantage of locality.
II. If capacity misses are most common, then the designers should consider increasing the total cache size so it can contain more lines. III. If conflict misses are most common, then the designers should consider increasing the cache’s associativity, in order to provide more flexibility when a collision occurs. A. III only B. I and II only C. II and III only D. I, II, and III E. None of the above
Best sources of preparation
(AUBG faculty lectures, Prof. Galetlly)
Address Translation in a combined Segmentation / Paging System
Best sources of preparation
(AUBG faculty lectures, Prof. Galetlly)
Lines in cache, each with a unique tag.
Blocks in memory comprising 4 words each
Tag: only so many blocks can fit in cache. Need to identify which one is which.
Extra Info
• SS Cyril & Methodius Sofia
Site:http://edcenter.elsys.bg/infocenter/bg/registration.html Registration is accepted only on the dates specified between 9 and 13 o’clock. Address: Sofia, “Vassil Aprilov” N3 Street Tel: 02 8464131 Test Date November 12, 2005 December 10, 2005 April 1, 2006 Registration Date September 17, 2005 October 15, 2005 February 4, 2006
Questions