1、“Introduction to Computer Science”計算機文化基礎USTB Computer Department“Introduction to Computer Science” Class : Total 30 hours Lecture 16 hours, Lab 14 hours Grading: Final exam 70% Others 30% Website: http:/Username: S 學號Password: 123456 Instructor : Taohong Zhang Contact: Contents Chapter 1: Computers

2、 and Digital Chapter 1: Computers and Digital BasicsBasics Chapter 2: Computer HardwareChapter 2: Computer Hardware Chapter 3: Computer SoftwareChapter 3: Computer Software Chapter 4: OSChapter 4: OS Chapter 5: NetworkChapter 5: Network Chapter 6: CompressChapter 6: CompressChapter 1 Computers and d

3、igital basics When you have completed this chapter you should be able to: Define the term “computer”, “microcomputer” know the digital revolution know the history of computer development know the type of computer and function of computer Differentiate between data and information, analog and digital

4、Describe how digital devices represent numbers, text, images, and soundmaster number and code. storage form of information number system and conversion of number Section A all things digitalThe DIGITAL REVOLUTIONWhat is the digital revolution?What is the digital revolution?The digital revolution is

5、an ongoing process of social, The digital revolution is an ongoing process of social, political, and economic change brought by digital political, and economic change brought by digital technology.technology.What technologies are fueling the digital What technologies are fueling the digital revoluti

6、on?revolution?Digital electronics, computers, communications, networks, Digital electronics, computers, communications, networks, the Web, and digitizationthe Web, and digitizationWhat caused the sudden upswing in computer What caused the sudden upswing in computer ownership?ownership?The network an

7、d the WebThe network and the WebDigitizationDigitization is the process of converting text, numbers, sound, is the process of converting text, numbers, sound, photos and video into data that can be processed by digital photos and video into data that can be processed by digital devices.devices. A co

8、mputerA computer network network is a group of computers is a group of computers linked by wired or wireless technology to linked by wired or wireless technology to share data and resources.share data and resources. The The InternetInternet is a global computer network is a global computer network T

9、he The WebWeb (short for World Wide Web) is a (short for World Wide Web) is a collection of linked documents, graphics, and collection of linked documents, graphics, and sounds that can be accessed over the Internet.sounds that can be accessed over the Internet.Section A all things digitalConcepts:C

10、ONVERGENCE What is convergence? (P.8 of E) How does convergence affect the typical consumer? QualitySection A all things digitalDIGITAL SOCIETYWhat is a computer? (Von Neumanns definition)A computer is a multipurpose device that accepts input, process data, stores data, and produces output, all acco

11、rding to a series of stored instructions (P14.) Adopt binary system Store InformationSection B Digital DevicesA computer accepts input “Input” : The words and symbols in a document, numbers for a calculation, pictures, temperatures from a thermostat, audio signals from a microphone, and instructions

12、 for completing a process; An input device gathers and translates input into a form that the computer can process. Keyboard is the main( standard ) input deviceSection B Digital DevicesA computer produce output “output” : results produced by a computer Reports Documents Graphs Music The main output

13、device: monitor printerSection B Digital DevicesA computer processes data data refers to the symbols that represent facts, objects, and ideas “process data” : Performing calculations Modifying documents and pictures Sorting lists of words or numbers (p15 F.1-13) Drawing graphs, A computer processes

14、data in a device called the central processing unit (CPU)Section B Digital DevicesA computer stores data “Store data” : perform automatically Memory - data waiting to be used Storage - data left on a permanent basis while it is not needed for process File - is a named collection of data that exists

15、on a storage mediumSection B Digital Devices computer program -The series of instructions that tells computer how to carry out processing tasks. Software- programs What kind of software do computer run? System software (P. 16) Application software (P. 16)Section B Digital DevicesWhats so significant

16、 to store instructions The Evolution of Computer History1.The First Generation- 1.The First Generation- Vacuum TubesVacuum Tubes (1946- (1946-1956)1956)（電子管（電子管）1946 ENIAC (Electronic numerical integrator and calculator) General-purpose electronic digital computer Wartime needs Decimal Programmed ma

17、nually1952 EDVAC (The Von Neumann Machine) (Electronic discrete variable automatic computer) Stored-program concept Had general structure and function The Evolution of Computer Weight:30t Storage:80 byte Speed:5000/s 1950s The birth of Computer Industry Commercial Computers IBM：Series of 700/70002.

18、The Second Generation: Transistors（1957-1964）（晶體管）（晶體管） 1947 Bell Labs invented transistor The late 1950s NCR, RCA Deliver the new technology IBM 7094 IBM 7094 Size of memory grew from 2K to 32K. Memory cycle time (the time to access one word of memory )fell from 30s to 1.4 s.Note: 1K = 210 =1024 Th

19、e Evolution of Computer 3. The Third Generation: Integrated Circuits (1965-1971)4. 4. Later Generations (1972-至今) Large-scale integration (LSI): 1000 components Very-large-scale integration (VLSI):100,000 components Microprocessors: -microcomputer(pc) All of the components of a CPU on a single chip

20、the difference of computer and microcomputer: 1) microprocessor; 2) bus structure The Evolution of Computer 代次代次起止年份起止年份所用電子元所用電子元器件器件數據處理方數據處理方式式運算速度運算速度應用領域應用領域第一代第一代19461957電子管電子管匯編語言、匯編語言、代碼程序代碼程序幾 千幾 千 幾幾萬次萬次/秒秒國 防 及 高國 防 及 高科技科技第二代第二代19581964晶體管晶體管高級程序設高級程序設計語言計語言幾 萬幾 萬 幾幾十 萬 次十 萬 次 /秒秒工程設計、工程

21、設計、數據處理數據處理第三代第三代19651970中、小規模中、小規模集成電路集成電路結構化、模結構化、模塊化程序設塊化程序設計、實時處計、實時處理理幾 十 萬幾 十 萬 幾百萬次幾百萬次/秒秒工業控制、工業控制、數據處理數據處理第四代第四代1970今今大規模、超大規模、超大規模集成大規模集成電路電路分時、實時分時、實時數據處理、數據處理、計算機網絡計算機網絡幾 百 萬幾 百 萬 上億條指上億條指令令/秒秒工 業 、 生工 業 、 生活 等 各 方活 等 各 方面面計算機發展的四個階段計算機發展的四個階段Chinese “神威神威” computer 384 CPU384 CPU 384,00

22、0,000,000/s384,000,000,000/s Memory size 48 GBMemory size 48 GB Harddisk size 2.5TB Harddisk size 2.5TB The Functions of Computer Functions:Functions: Science computation Information disposal Process control Computer aided engineer (CAE) Artificial intelligence (AI)The Category of ComputerCategory (

23、usage, cost, size, capability)Category (usage, cost, size, capability)commonly used computer categoriescommonly used computer categories Microcomputer (personal computer) servers Mainframes1) Supercomputers Personal computer Microprocessor-based computing device for an individualWorkstation: Two mea

24、nings 1. an ordinary personal computer connected to a network 2. powerful desktop computers for high-performance tasks (such as CAD)Section B Digital Devices2. Server Serve computers on a network supplying dataClient: requests data from a server is referred to as a client Section B Digital Devices3.

25、 Mainframe Large, fast, expensive;Business, government;Provide centralized storage, processing and management for large amount of data;simultaneously handle thousands of users.Section B Digital Devices4. Supercomputer - the fastest computers in the world Fastest, most expensive;Designed for “compute

26、r-intensive” task, such as molecular calculations, atmospheric modeling or simulating nuclear explosionsSection B Digital Devices計算機的分類數 字 計 算 機數 字 計 算 機模 擬 計 算 機模 擬 計 算 機數模混合計算機數模混合計算機按處理對象按處理對象按使用范圍按使用范圍通 用 計 算 機通 用 計 算 機專 用 計 算 機專 用 計 算 機按規模按規模 巨 型 計 算 機巨 型 計 算 機大大/ /中型計算機中型計算機小 型 計 算 機小 型 計 算 機微

27、 型 計 算 機微 型 計 算 機工作站或服務器工作站或服務器Data representation basic:what is data?data refers to the symbols that represent people, events, things, and ideas. data can be a name, a number, the colors in a photo, or the note in a musical composition.The difference of Data and informationdata is used by machine,

28、such as computer; information is used by humans.Section C. Digital Data RepresentationDigital Data Representation Data representationthe form data is stored, processed, and transmitted Analog and digital the difference between analog and digital Digital data is text, number that converted into discr

29、ete digits such as 0s and 1s. Analog data is represented using an infinite scale of values.Section C Digital Data Representation1. Representing number Numeric Data Numbers used in arithmetic operations Binary number system0 and 1Section C Digital Data Representation Computer store, process and trans

30、mit data with binary form A computer uses a bit as the building block for more complex messages, which are constructed with a series of bits. 1 bit can convey two units of information.Section C Digital Data Representation1. Representing numberunits of binary system 1 bit 1 byte = 8 bit 1 word = 2 by

31、te 1kB (byte) = 210 B 1MB (MegaByte)= 210 KB 1GB (GigaByte)= 210 MB 1TB (Tricro) = 210 GBNumber(數制數制)Some Notation:Some Notation:Base/ radix （基數） Digits （數字符號）Weight （位權）數數制制 基基數數 數數字字符符號號 十十進進制制 10 0，1，2，3，4，5，6，7，8，9 二二進進制制 2 0，1 八八進進制制 8 0，1，2，3，4，5，6，7 十十六六進進制制 16 0，1，2，3，4，5，6，7，8，9，A，B，C，D，E，F

32、 Section C Digital Data RepresentationMultinomial unwrapped from the number according to the weight:1) The Decimal System：(4723.75)10= 4103710221013100 710-1510-22) The Binary System： (11101. 01)2 =124123122021120 02-112-2Section C Digital Data Representation1. Representing number3) The hexadecimal

33、system Base, or radix of 16, digits (0,1,2,3,4,5,6,7,8,9, A, B, C, D, E, F) S = . . . s2 s1 s0.s-1 s-2 s-3 . . S=Sn116 n1+Sn216n2+S116 1+S0160 +S1161+Sm16m F1.3=15*161+1*160+3*16-1Section C Digital Data Representation1. Representing number4) The octal system Base, or radix of 8 , digits (0,1,2,3,4,5

34、,6,7) S = . . . s2 s1 s0.s-1 s-2 s-3 . . S=Sn18n1+Sn28n2+S181+S080 +S181+Sm8m 23.3=2*81+7*80+3*8-183= ?Section C Digital Data Representation1) Conversion between Binary 1) Conversion between Binary and Decimaland Decimal To convert from decimal to binary, the integer and fractional parts are handled

35、 separately.Number Conversiona) Convert decimal integer N into binary form: N =(1 2k) + (Rk 2k-1) + . . + (R3 22) + (R2 21) + (R1 20) Repeated divisionEx. Decimal 11 Quotient Remainder11/2 = 5 15/2 = 2 12/2 = 1 01/2 = 0 1Number Conversion1011(11)10= (1011)2 b) b) FractionalFractional part involved r

36、epeated part involved repeated multiplication.multiplication. F = (a-1 1/2)+( a-2 1/22)+( a-3 1/23)+. This process is not necessarily exact. Ex. Decimal 0.81 Ex. Decimal 0.81 Product Integral Part .1 1 0 0 1 10.81 2 = 1.6210.62 2 = 1.2410.24 2 = 0.4800.48 2 = 0.9600.96 2 = 1.9210.92 2 = 1.841 (0.81)

37、10= (0.110011)2, (approximate) Ex. Decimal 0.25Ex. Decimal 0.25 Product Integral part 0.252 = 0.5 0 0.502 = 1.0 1 0.2510 = 0.01 (exact)0 1 2) Conversion between Hexadecimal and 2) Conversion between Hexadecimal and DecimalDecimalBase 16 (0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F)0000=0 1000=80001=1 1001=90010

38、=2 1010=A0011=3 1011=B0100=4 1100=C0101=5 1101=D0110=6 1110=E0111=7 1111=FHexadecimal DecimalHexadecimal DecimalEx.1A16 = (116 161)+( A16 160) = (110 161)+( 1010 160) = 26 Binary Hexadecimal 1101 1110 0001 = DE116 D E 1 3) Conversion between Octal and Decimal3) Conversion between Octal and DecimalBa

39、se 8 (0,1,2,3,4,5,6,7)000=0 001=1 010=2 011=3 100=4 101=5 110=6 111=7 Octal DecimalOctal DecimalEx. 178 = (18 81)+( 78 80) = (8)+ (7) = 15 Binary OctalBinary Octal 101 111 001 = 5718 5 7 1整型數的存儲機器數：將一個數在機器中的存儲形式（即編碼）稱為機器數。 帶符號數的最高位用來表示數的符號，一般用“0”表示“+”，用“1”表示“-”。-816-0 2550 65,535 Arithmetic and Logi

40、c Rule Arithmetic加 0+0=0 1+0=0+1=1 1+1=10減 0-0=0 1-0=1 1-1=0 0-1=1乘 0*0=0 0*1=1*0=0 1*1=1除 0/1=0 1/1=1Logic與 00=0 01=0 10=0 11=1或 00=0 01=1 10=1 11=1非 非0為1 非1為0Example of Arithmetic and Logic ex3ex3：a = 1100a = 1100，b = 0110b = 0110 abab、abab、a a 1100 1100 1100 0110 0110 0110 0110 邏輯非為：邏輯非為： 1110 01

41、00 00111110 0100 0011 ex1ex1： 101. 01101. 01 +110. 01+110. 01 1011. 10 1011. 10ex2ex2： 101. 111101. 111 + 11. 011 + 11. 011 1001. 010 1001. 010 2. Representing symbols How to denote character? a) ASCII coding （ American Standard Code American Standard Code for Information Interchangefor Information

42、Interchange）uses 7 bits to represent 27 Symbols (128 symbols), including uppercase and lowercase letters, special control codes, numerals, and punctuation symbols. Section C Digital Data RepresentationASCII Rule One byte (8 bits binary codeOne byte (8 bits binary code) ) represents one characterrepr

43、esents one character0The top of byte is “0”The others(7 bits) can have 128 binary codes. Ex ：0000 0000-0111 1111Represent 128 characters.Section C Digital Data Representation ASCII RuleA為（為（0100 0001）2 = 65記住：記住：0字符的字符的ASCII碼是碼是48A字符的字符的ASCII碼是碼是65a字符的字符的ASCII碼是碼是97a與與A 的的ASCII碼之差是碼之差是32b) Chinese c

44、ode: GB-2312信息交換用漢字編碼字符集信息交換用漢字編碼字符集基本集基本集/ / GB2312-80GB2312-80 74457445 Chinese and graph symbolChinese and graph symbol： commoncommon：202202； sequencesequence：6060； numbernumber：2222； EnglishEnglish：5252；JapanJapan：169169； GreekGreek：4848; ; RussiaRussia：6666 ChineseChinese：67636763；( (37553755；3

45、0083008) ) Two bytesTwo bytes represent each Chinese or symbol. represent each Chinese or symbol.Section C Digital Data Representation高八位高八位低八位低八位 漢字的編碼各種代碼之間的關系：各種代碼之間的關系：漢字輸入漢字輸入輸入碼輸入碼（外碼）（外碼）國標碼國標碼機機內內碼碼輸出碼輸出碼（字形碼）（字形碼）漢字輸出漢字輸出高位置高位置“1”包括：信息交換碼（國標碼）、機內碼、輸入碼和輸包括：信息交換碼（國標碼）、機內碼、輸入碼和輸出碼出碼機內碼（亦稱內碼）：漢

46、字（符號）在計算機內部的二進制代碼。 輸入碼（外碼） 輸入碼：漢字輸入時使用的編碼。 輸出碼（字模、字型碼）16x16點陣漢字及編碼24x24點陣漢字32x32點陣漢字Difference:1. Image quality;2. The amount required to store the image;3. The amount of time required to transmit the image4. How easy to modify the image and so on3. Representing ImagesSection C Digital Data Represen

47、tation Bitmap graphic method of a black-and-white image monochrome graphic1 pixel can be represented by 1 bit.Grayscale graphicsGrayscale graphic: display a bitmap image using shades of gray or “gray classes” (black and white photos)256-grayscale graphic u1 pixel can be represented by 8 bits.uA full

48、 screen 256-grayscale graphic at 640 * 480 resolution requires 307,200 bytes. Color graphics Color graphic: display a bitmap image using coloru 16 color : 1 pixel can have 16 color, need 4 bits u256 color:1 pixel can have 256 color, need 8 bits u16.7 million colors (24-bit or true-color graphic) col

49、or: need 3 bytes to present : Red Green Bluewidth：271height：300color：2size：9.9 KBwidth：271height：300color：4size：19.8 KBExample of graphSection C Digital Data Representationwidth：271height：300color：256size：79.4 KBwidth：271height：300color：true colorsize：238.2 KBExample of graphSection C Digital Data R

50、epresentationComputation for storage To store a true color image To store a true color image resolution 352288 Color byte 3B storage= 352288 3=297KB If enhance image resolutionIf enhance image resolution storage= 7681024 3=2.25MBDecrease the graphic storage and transmission time Approximator: Making

51、 an image physically smaller by shrinking it or cropping it will decrease the number of pixels required to represent the graphic. Compression: Size of graphic file can be reduced by technique known as compression Dithering: reduce the number of colors in a graphic.Vector graphic and Digital Video Ve

52、ctor graphicDifference between vector graphic and bitmap graphic?vector graphic: consist of a set of instructions that recreates a picture.You can use vector graphics software to draw a picture, CIRCLE 40 Y200 150 means: create a circle with 40 pixels radius, color it yellow, and place the center of

53、 the circle 200 pixels from the left of the screen and 150 pixels from the top of the screen Digital videoComposed of a series of frames. Each frame is a still picture. A video display 30 frames per second. Waveform audio: a digital representation of sound.To record sound, samples of the sound are c

54、ollected at periodic intervals and stored as numeric data.Sampling rate : the number of times per second that the sound is measured during the recording process. Expressed in hertz(Hz)4. Representing Audio Example of Audio encode 采樣點t1t2t3t4t5t6t7. 幅值0011010101111001101111011110.Analog signals techn

55、ique parameterSampling rate Sampling rate ( Hz ex:( Hz ex:11.02511.025kHz/kHz/22.0522.05kHz)kHz)Sampling precision Sampling precision (bit(bit ex:8 bits/16 bitsex:8 bits/16 bits) )Track number Track number (single(single、doubledouble) )采樣頻率采樣頻率11KHz 8位量化位量化 采樣頻率采樣頻率22KHz 16位量化位量化Circuits and chips W

56、hatWhats a computer chip?s a computer chip?the terms computer chip, microchip, and the terms computer chip, microchip, and chip originated as technical jargon for chip originated as technical jargon for integrated egrated circuit.Section C Digital Data Representation integrated circuit is

57、 an super-thin slice of semiconducting material packed with microscopic circuit elements, such as wires, transistors, capacitors, logic gates, and resistors.(p27 f1-30)Section D. Digital processingPrograms and instruction sets: How do digital devices process data? The data is manipulated under the c

58、ontrol of a computer program. The human-readable version of a program is called source code.How does source code get converted?The procedure for translating source code into 0s and 1s can be accomplished by a compiler or an interpreter. A compiler converts all the statements in a program in a single batch, and the resulting collection of instructions, called object code, is placed in a new file.(p30 f1-34)Digital processingS