News Department of Computer Science Reading This Week - PowerPoint PPT Presentation

University of British Columbia News Department of Computer Science Reading This Week Undergraduate Events CPSC 111, Intro to Computation Events this week Drop-In Resume Edition Session 2009W2: Jan-Apr 2010 ■ reminder: no class next time: this Friday Jan 8! ■ Ch 1.1 - 1.2: Computer Anatomy How to Prepare for the Tech Date: Mon. Jan 11 Career Fair Time: 11 am – 2 pm Date: Wed. Jan 6 Tamara Munzner Location: Rm 255, ICICS/CS Bldg Time: 5 – 6:30 pm ■ UBC CS news Location: DMP 110 Industry Panel Speakers: Managers from Google, Resume Writing Workshop (for IBM, Microsoft, TELUS, etc. non-coop students) Date: Tues. Jan 12 Date: Thurs. Jan 7 Hardware, Memory, Languages Time: Panel: 5:15 – 6:15 pm; Time: 12:30 – 2 pm Networking: 6:15 – 7:15 pm Location: DMP 201 Location: Panel: DMP 110; CSSS Movie Night Networking: X-wing Undergrad Lecture 2, Wed Jan 6 2010 Lounge Date: Thurs. Jan 7 Time: 6 – 10 pm Tech Career Fair Location: DMP 310 borrowing from slides by Kurt Eiselt, Wolfgang Heidrich, Date: Wed. Jan 13 Movies: “Up” & “The Hangover” (Free Popcorn & Time: 10 am – 4 pm Alan Hu Pop) Location: SUB Ballroom http://www.cs.ubc.ca/~tmm/courses/111-10 1 2 3 4 Recap: Procedures and Algorithms Why Being Precise/Stupid Isn’t Easy Correction / Recap: Prerequisites Recap: Processes, Procedures, and Programs ■ Mathematics 12 is the prerequisite ■ process: what happens when a computer follows a ■ human languages are very different from computer Here’s why we get frustrated when we start to learn languages: they’re ambiguous ■ or any math course at UBC procedure - it’s a procedure in execution to write programs to make computers do stuff: ■ humans bring huge amounts of knowledge to understanding ■ if you have not taken it you will be dropped from the course meaning of sentence ■ see CS advisors if you need prerequisite waived because of ■ procedure: collection of instructions in some An algorithm is ■ we apply it automatically and unconsciously equivalent work meaningful order that results in useful behavior on ■ many meanings per word ■ current stuff • a finite procedure ■ sentence structure behalf of the device that executes the instructions ■ you cannot get credit for both 111 and new 110 course • written in a fixed symbolic vocabulary ■ context of conversation ■ you cannot get credit for 101 if you take it after or concurrently • governed by precise instructions ■ how the world workd with 111 ■ program: when instructions are written in symbolic • moving in discrete steps, 1, 2, 3, ... ■ how language is used ■ you CAN get credit for 111 if you take it after 101! • whose execution requires no insight, cleverness, language that can be executed by a computer ■ you count on listener to disambiguate without even noticing intuition, intelligence, or perspicuity ■ we can get away with relatively short and imprecise sentences • and that sooner or later comes to an end We don’t have a lot of practice at being stupid! 5 6 7 8 Why Being Precise/Stupid Isn’t Easy Physical Hardware Computer Design Introduction to Computer Hardware ■ imagine a world where there is no ambiguity ■ “Computer science is how to harness the physical ■ it’s hard to figure out how to make things do ■ Objectives: world to help us think. ” - Alan Hu ■ that’s computer programming! computation ■ to identify and explain the purpose of core hardware components ■ all digital computers for over 50 years have had: ■ everyone starts out imprecise ■ to understand the way data is represented in ■ harnessing the physical world to help us think ■ same basic organization ■ everyone gets frustrated while learning this stuff memory ■ binary representation of data ■ how to get things that have computational behavior? ■ you are not alone ■ numerically addressed memory ■ technology dependent: ■ you can succeed at this ■ Understanding the hardware that runs our programs ■ sticks, gears, relays, vacuum tubes, transistors, ■ fetch-decode-execute operation cycle can help us understand the programs' behavior, DNA, ... especially when they misbehave. ■ how to control that behavior to do interesting things ■ we’ll only have a brief glance here 9 10 11 12 Computer Hardware Overview Computer Hardware Overview Binary Data Representation Memory ■ All programs and data on a computer are ■ Some of computer programming is resource management represented using only symbols 0 and 1 ■ As beginning programmers, the resource that you’ll be ■ This simple binary system is encoded in all of our concerned with most is memory digital hardware devices: ■ Most programming languages do a lot of the work for you ■ Magnetic disks: magnetic material can be polarized ■ More on this soon to one of two extremes (north or south) to represent a 0 or a 1. ■ Memory: each byte consists of 8 bits; each bit is a kind of electronic switch that is either off or on representing a 0 or a 1. 13 14 15 16

Memory Memory Units of Memory Storage What Can Be Represented By A Byte? ■ Memory consists of a series of locations, each having a ■ 256 different characters from your keyboard unique address, that are used to store programs and data. ■ Java actually uses 2 bytes to represent a character We measure units of memory in terms of bytes: ■ how many characters is that? ■ When data is stored in a memory location, the data that was ■ 256 different shades of gray in a black and white image previously stored there is overwritten and destroyed. ■ Each memory location stores one byte (or 8 bits) of data. ■ 256 colors or shades of color in a color image Unit Symbol # of bytes ■ Each bit is a 0 or a 1 ■ More on this soon byte (8 bits) 2 0 = 1 ■ 256 frequencies or tones to be played through a speaker kilobyte KB 2 10 = 1024 Data values are 5802 stored in memory ■ 256 of anything that can be represented as discrete entities 5803 10110101 10110101 megabyte MB 2 20 = 1024 2 locations – more 5804 than one location gigabyte GB 2 30 = 1024 3 5805 may be used if the ■ part of an instruction for a computer 5806 data is large. terabyte TB 2 40 = 1024 4 5807 Address 17 18 19 20 Memory Mass storage/long-term memory Central processing unit Central processing unit ■ CPU executes instructions in a continuous cycle ■ known as the “fetch-decode-execute” cycle ■ CPU has dedicated memory locations known as registers ■ One register, the program counter , stores the address in memory of the next instruction to be executed fetch Macintosh SE in 1987 MacBook Pro in 2008 1 megabyte (MB) of memory 2 gigabytes (GB) of memory execute decode 1000 times more memory capacity in 20 years A disk drive without its protective case 1000 times greater processing speed Approximately the same price 21 22 23 24 Central processing unit Central processing unit Instructions Programming Languages ■ Implication of the fetch-decode-execute cycle ■ Objectives ■ we control the computer to make it do what we want Understand what is meant by computer ■ by giving it a sequence of little steps for it to do programming. ■ these steps are the instructions in a programming Understand the difference between ■ language machine/assembly language and a high-level computer language. Understand what compilers and interpreters are, ■ and why we use them. Write, compile, and run a simple Java program. ■ 25 26 27 28 What is Computer Programming? What is a Computer? What is a Computer? Computer Programming How is a computer different from a video game How is a computer different from a video game console? Or a DVD player? Or a telephone? Or a console? Or a DVD player? Or a telephone? Or a Input Devices Output Devices bank machine? bank machine? Central Processing Unit The computer is general . It can be all of the other Computer devices. Program Memory Making the computer do what we want is called Mass Storage Devices programming the computer. 29 30 31 32