机械式(转轮)11526.pptx

《机械式(转轮)11526.pptx》由会员分享，可在线阅读，更多相关《机械式(转轮)11526.pptx（82页珍藏版）》请在得力文库 - 分享文档赚钱的网站上搜索。

1、IntroductionIntroductionChapter 0:Introduction Computer science is the discipline that seeks to build a scientific foundation for such topics as computer design computer programming information processing etc.Computer science provides the underpinnings for todays computer applications as well as the

2、 foundations for tomorrows applications.Algorithms:Definitions Algorithm a set of steps that defines how a task is performed.Program a representation of an algorithm.Programming the process of developing a program.Software programs+algorithms.Hardware machinery:whatever isnt software.Computer Histor

3、yComputer HistoryWhat is computer?An AbacusOrigins of Computing Machines Early computing devices Abacus:positions of beads represent numbers0 1600s-1800s 機械式(轉輪)積體電路 積體電路可以分為以下幾類：小規模積體電路(SSI 英文全名為 Small-Scale Integration,幾十個邏輯閘以內)。中規模積體電路(MSI 英文全名為 Medium-Scale Integration,幾百個邏輯閘）。大規模積體電路(LSI 英文全名為

4、Large-Scale Integration,幾萬個邏輯閘）。超大規模積體電路(VLSI 英文全名為 Very-large-scale integration,幾十萬個邏輯閘以上）。甚大規模積體電路(ULSI 英文全名為 Ultra-Large Scale Integration,百萬個邏輯閘以上）。Early computing devices Gear-based machines(1600s-1800s)Positions of gears represent numbers Blaise Pascal,Wilhelm Leibniz,Charles Babbage(progressi

5、on of flexibility)Blaise Pascal 1623-1662,France Pascal Machine Addition algorithm Charles Babbages Machine(1792-1871)Print output values on paper Programmable His assistant Augusta Ada Byron is often identified today as the worlds first programmer.Punched Card Idea from Jacquard Loom in 1801The Lon

6、don Science Museums replica Assembled after his deathby Babbages son,using parts found in his laboratory.Punched Cards Early data storage:punched cards First used in Jacquard Loom(1801)to store patterns for weaving cloth Stored programs in Babbages Analytical Engine Popular through the 1970sJacquard

7、 LoomJacquard LoomPunched CardsEarly computers Based on mechanical relays(繼電器)1940:Model K:Stibitz at Bell Laboratories 1944:Mark I:Howard Aiken and IBM at Harvard Based on vacuum tubes(真空管)1937-1941:Atanasoff-Berry Computer(ABC)at Iowa State The first“computer”,NO CPU,DRAM 1940s:Colossus:secret Ger

8、man code-breaker Decode German messages during the latter part of World War II 1940s:ENIAC:Mauchly&Eckert at U.of Penn.Mark I,ASCC Howard Aiken,IBM at Harvard,1944 ASCC 是由開關、繼電器、轉軸以及離合器所構成。它使用了765,000 個元件 組裝大小為16 公尺長，2.4 公尺高，2 呎深。重達4500 公斤。其基本計算單元使用同步式機械，所以它有一跟長15 公尺的傳動軸，並由一顆4 千瓦的馬達所驅動。馬可一號可以儲存72 組數

9、據，每組數據有23 位十進位數字。每秒可執行3 次加法或是減法。一個乘法則須6 秒，一個除法須15.3 秒，計算一個對數或是一個三角函數需花費超過一分鐘。打卡紙讀取、執行每一道指令。The Mark I computer電腦的演進 1642 巴斯卡加法器 1804 法國織布工人查卡得發明能用不同打孔卡片自動來編織圖案的織布機 1822 英國劍橋大學的巴貝奇發明差分機，可做簡單的四則運算 1833 巴貝奇建造分析機失敗，但分析機構想已具有今日電腦的基本結構，巴貝奇因而有電腦之父的尊稱。1886 美國何樂里設計出以打孔卡片來儲存資料的計算機器 1906 美國費樂斯(Forest)發明了真空管電腦之

10、父 巴貝奇(babbage)巴貝奇的差分機 范紐曼(Von Neumann)電腦的演進 1939 美國愛荷華州立大學製造出第一部電腦ABC 1946 美國賓州大學和軍方合作製造出ENIAC 電腦，范紐曼提出內儲程式的觀念，被譽為電子電腦之父 1947 美國貝爾實驗室發明了電晶體 1949 英國劍橋大學完成第一部大型內儲程式電腦EDSAC 1951 美國Sperry Rand 公司生產UNIVAC-1，第一部大量製造的商業電腦 電腦的演進(cont.)1954 美國貝爾實驗室製出第一台以電晶體為主要元件的電腦(TRADIC)1958 美國德州儀器公司發明了積體電路(IC Integrated C

11、ircuit 1964 美國國際商業機器公司(IBM)用IC 為主元件開發出System360 電腦 1970 開始有電腦使用超大型積体電腦(VLSI)電腦的演進(cont.)1971 美國Intel 公司發表第一個微處理機4004 1977 美國Apple 公司推出APPLE II 電腦：採封閉性硬体系統架構。1981 美國IBM 公司推出個人電腦，稱為IBM PC：採開放性硬体系統架構，造成IBM 相容型電腦的大量生產。1993,PentiumEDSAC 1949 劍橋大學 真空管為元件的電腦 APPLE II IBM computer 1981Chapter 1Data StorageC

12、hapter 1:Data Storagen 1.1 Bits and Their Storagen 1.2 Main Memoryn 1.3 Mass Storagen 1.4 Representing Information as Bit Patternsn 1.5 The Binary Systemn 1.6 Storing IntegersChapter 1:Data Storage(continued)n 1.7 Storing Fractionsn 1.8 Data Compressionn 1.9 Communications ErrorsBits and their meani

13、ngn Bit=Binary Digit=a symbol whose meaning depends on the application at hand.n Some possible meanings for a single bitn Numeric value(1 or 0)n Boolean value(true or false)n Voltage(high or low)Bit patternsn All data stored in a computer are represented by patterns of bits:n Numbersn Text character

14、sn Imagesn Soundn Anything elseBoolean operationsn Boolean operation=any operation that manipulates one or more true/false valuesn Can be used to operate on bitsn Specific operationsn ANDn ORn XORn NOTFigure 1.1 The Boolean operations AND,OR,and XOR(exclusive or)Gatesn Gates=devices that produce the

15、 outputs of Boolean operations when given the operations input valuesn Often implemented as electronic circuitsn Provide the building blocks from which computers are constructedFigure 1.2 A pictorial representation of AND,OR,XOR,and NOT gates as well as their input and output valuesFlip-flopsn Flip-

16、flop=a circuit built from gates that can store one bit of data.n Has an input line which sets its stored value to 1n Has an input line which sets its stored value to 0n While both input lines are 0,the most recently stored value is preservedFigure 1.3 A simple flip-flop circuitFigure 1.4 Setting the

17、 output of a flip-flop to 1Figure 1.4 Setting the output of a flip-flop to 1(contd)Figure 1.4 Setting the output of a flip-flop to 1(contd)Figure 1.5 Another way of constructing a flip-flopOther storage techniquesn Dynamic memory must be replenished periodically Example:capacitorsn Volatile memory h

18、olds its value until the power is turned off Example:flip-flopsn Non-volatile memory holds its value after the power is off Example:magnetic storagen Read-only memory(ROM)never changes Examples:flash memory,compact disksHexadecimal notationn Hexadecimal notation=a shorthand notation for streams of b

19、its.n Stream=a long string of bits.n Long bit streams are difficult to make sense of.n The lengths of most bit streams used in a machine are multiples of four.n Hexadecimal notation is more compact.n Less error-prone to manually read,copy,or writeFigure 1.6 The hexadecimal coding systemMain memory:c

20、ellsn Cells=manageable units(typically 8 bits)into which a computers main memory is arranged.n Byte=a string of 8 bits.n High-order end=the left end of the conceptual row in which the contents of a cell are laid out.n Low-order end=the right end of the conceptual row in which the contents of a cell

21、are laid out.n Least significant bit=the last bit at the low-order end.Figure 1.7 The organization of a byte-size memory cellMain memory addressesn Address=a“name”to uniquely identify one cell in the computers main memoryn The names for cells in a computer are consecutive numbers,usually starting at

22、 zeron Cells have an order:“previous cell”and“next cell”have reasonable meaningsn Random Access Memory=memory where any cell can be accessed independentlyFigure 1.8 Memory cells arranged by addressMeasuring memory capacity:Not quite like the metric systemn“Kilo-”normally means 1,000;Kilobyte=210=102

23、4n“Mega-”normally means 1,000,000;Megabyte=220=1,048,576n“Giga-”normally means 1,000,000,000;Megabyte=230=1,073,741,824Mass Storage Systemsn Non-volatile;data remains when computer is offn Usually much bigger than main memoryn Usually rotating disksn Hard disk,floppy disk,CD-ROMn Much slower than ma

24、in memoryn Data access must wait for seek time(head positioning)n Data access must wait for rotational latencyFigure 1.9 A disk storage systemFigure 1.10 CD storage formatFigure 1.11 A magnetic tape storage mechanismFilesn File=the unit of data stored on a mass storage system.n Logical record and Fi

25、eld=natural groups of data within a filen Physical record=a block of data conforming to the physical characteristics of the storage device.n Buffer=main memory area sometimes set aside for assembling logical records or fields of a fileFigure 1.12 Logical records versus physical records on a diskFigu

26、re 1.13 The message“Hello.”in ASCIIRepresenting textn Each printable character(letter,punctuation,etc.)is assigned a unique bit pattern.n ASCII=7-bit values for most symbols used in written English textn Unicode=16-bit values for most symbols used in most world languages todayn ISO proposed standard

27、=32-bit valuesRepresenting numeric valuesn Binary notation uses bits to represent a number in base twon Limitations of computer representations of numeric valuesn Overflow happens when a number is too big to be representedn Truncation happens when a number is between two representable numbersFigure

28、1.14 The sound wave represented by the sequence 0,1.5,2.0,1.5,2.0,3.0,4.0,3.0,0Figure 1.15 The base ten and binary systemsFigure 1.16 Decoding the binary representation 100101Figure 1.17 An algorithm for finding the binary representation of a positive integerFigure 1.18 Applying the algorithm in Fig

29、ure 1.15 to obtain the binary representation of thirteenFigure 1.19 The binary addition factsFigure 1.20 Decoding the binary representation 101.101Representing Integersn Unsigned integers can be represented in base twon Signed integers=numbers that can be positive or negativen Twos complement notati

30、on=the most popular representationn Excess notation=another less popular representationFigure 1.21 Twos complement notation systemsFigure 1.22 Coding the value-6 in twos complement notation using four bitsFigure 1.23 Addition problems converted to twos complement notationFigure 1.24 An excess eight

31、conversion tableFigure 1.25 An excess notation system using bit patterns of length threeFigure 1.26 Floating-point notation componentsFigure 1.27 Coding the value 258Figure 1.29 The ASCII codes for the letters A and F adjusted for odd parityFigure 1.30 An error-correcting codeFigure 1.31 Decoding the pattern 010100 using the code in Figure 1.30谢谢观看/欢迎下载BY FAITH I MEAN A VISION OF GOOD ONE CHERISHES AND THE ENTHUSIASM THAT PUSHES ONE TO SEEK ITS FULFILLMENT REGARDLESS OF OBSTACLES.BY FAITH I BY FAITH