计算机基础全英文版的课件

1、“introduction to computer science”计算机文化基础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 学号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)（电子管（电子管）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）（晶体管）（晶体管） 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电子元所用电子元器件器件数据处理方数据处理方式式运算速度运算速度应用领域应用领域第一代第一代19461957电子管电子管汇编语言、汇编语言、代码程序代码程序几 千几 千 几几万次万次/秒秒国 防 及 高国 防 及 高科技科技第二代第二代19581964晶体管晶体管高级程序设高级程序设计语言计语言几 万几 万 几几十 万 次十 万 次 /秒秒工程设计、工程

21、设计、数据处理数据处理第三代第三代19651970中、小规模中、小规模集成电路集成电路结构化、模结构化、模块化程序设块化程序设计、实时处计、实时处理理几 十 万几 十 万 几百万次几百万次/秒秒工业控制、工业控制、数据处理数据处理第四代第四代1970今今大规模、超大规模、超大规模集成大规模集成电路电路分时、实时分时、实时数据处理、数据处理、计算机网络计算机网络几 百 万几 百 万 上亿条指上亿条指令令/秒秒工 业 、 生工 业 、 生活 等 各 方活 等 各 方面面计算机发展的四个阶段计算机发展的四个阶段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计算机的分类数 字 计 算 机数 字 计 算 机模 拟 计 算 机模 拟 计 算 机数模混合计算机数模混合计算机按处理对象按处理对象按使用范围按使用范围通 用 计 算 机通 用 计 算 机专 用 计 算 机专 用 计 算 机按规模按规模 巨 型 计 算 机巨 型 计 算 机大大/ /中型计算机中型计算机小 型 计 算 机小 型 计 算 机微

27、 型 计 算 机微 型 计 算 机工作站或服务器工作站或服务器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(数制数制)some notation:some notation:base/ radix （基数） digits （数字符号）weight （位权）数数制制 基基数数 数数字字符符号号 十十进进制制 10 0，1，2，3，4，5，6，7，8，9 二二进进制制 2 0，1 八八进进制制 8 0，1，2，3，4，5，6，7 十十六六进进制制 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整型数的存储机器数：将一个数在机器中的存储形式（即编码）称为机器数。 带符号数的最高位用来表示数的符号，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减 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与 00=0 01=0 10=0 11=1或 00=0 01=1 10=1 11=1非 非0为1 非1为0example of arithmetic and logic ex3ex3：a = 1100a = 1100，b = 0110b = 0110 abab、abab、a a 1100 1100 1100 0110 0110 0110 0110 逻辑非为：逻辑非为： 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为（为（0100 0001）2 = 65记住：记住：0字符的字符的ascii码是码是48a字符的字符的ascii码是码是65a字符的字符的ascii码是码是97a与与a 的的ascii码之差是码之差是32b) chinese c

44、ode: gb-2312信息交换用汉字编码字符集信息交换用汉字编码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 汉字的编码各种代码之间的关系：各种代码之间的关系：汉字输入汉字输入输入码输入码（外码）（外码）国标码国标码机机内内码码输出码输出码（字形码）（字形码）汉字输出汉字输出高位置高位置“1”包括：信息交换码（国标码）、机内码、输入码和输包括：信息交换码（国标码）、机内码、输入码和输出码出码机内码（亦称内码）：汉

46、字（符号）在计算机内部的二进制代码。 输入码（外码） 输入码：汉字输入时使用的编码。 输出码（字模、字型码）16x16点阵汉字及编码24x24点阵汉字32x32点阵汉字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 采样点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) )采样频率采样频率11khz 8位量化位量化 采样频率采样频率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