计算机英语关于学生的简短笔记.doc

Computer English Teaching Plan Chapter 1: Computer and Computer Science I. COMPUTER Commonly Operating Machine Particularly Used for Trade, Education & Research1.A computer is a machine that manipulates data according to a list of instructions. 2.Computer can access & process data millions of times faster than humans can. 3.A computer can store data & information in its memory, process them & produce the desired results. 4. Computer can do a lot of different tasks such as playing games, railway reservation etc. II. STRENTGHS & WEAKNESSES OF A COMPUTER1.SPEED: Computers are much faster as compared to human beings. 2.HIGH STORAGE CAPACITY: Computers can store a large amount of information in very small space. 3.ACCURACY: Computers can perform all the calculation & comparisons accurately provided the hardware does not malfunction. 4. VERSATILITY: Computers can perform repetitive jobs efficiently. III. TYPES OF COMPUTERThe computers have been classified into three categories.Digital Computers- The digital computer work upon discontinuous data. They convert the data into digits & all operations are carried out on these digits at extremely fast rates. Digital Computers are much faster than analog computers. Computers used for business & scientific applications are digital computers. Analog Computers - In analog computers continuous quantities are used. The main advantage of analog computer is that all calculations take place in parallel & hence these are faster. Analog computers are mostly used in engineering & scientific applications. Hybrid Computers - In these computers some calculations take place in analog manner & rest of them take place in digital manner. Hybrid computers are used in hospitals where analog part is responsible for measurement of heart beat. They are also used in weather forecasting. IV.LIMITATIONS OF A COMPUTER1. Lack of decision making power: Computer cant decide on their own. They do not possess this power which is a great assert of human brings. 2. IQ Zero: Computers are dumb machines with zero IQ. They need to be told each & every step, however minute it may be. V. FEATURES OF COMPUTERFIRST GENERATION 1. Use of vacuum tubes2. Big & Clumsy3. High Electricity Consumption4. Programming in Mechanical Language5. Larger AC were needed6. Lot of electricity failure occurredSECOND GENERATION1. Transistors were used2. Core Memory was developed3. Faster than First Generation computers4. First Operating System was developed5. Programming was in Machine Language & Assembly Language6. Magnetic tapes & discs were used7. Computers became smaller in size than the First Generation computers8. Computers consumed less heat & consumed less electricityTHIRD GENERATION 1. Integrated circuits developed2. Power consumption was low3. SSI & MSI Technology was used4. High level languages were usedFOURTH GENERATION 1. LSI & VLSI Technology used2. Development of Portable Computers3. RAID Technology of data storage4. Used in virtual reality, multimedia, simulation5. Computers started in use for Data Communication6. Different types of memories with very high accessing speed & storage capacityFIFTH GENERATION COMPUTERS1. Used in parallel processing2. Used superconductors3. Used in speech recognition4. Used in intelligent robots5. Used in artificial intelligenceS.NoParametersFirst GenerationSecond GenerationThird GenerationFourth GenerationFifth Generation1.Year195019601965197519822.Electronic ComponentVacuum Tubes.Transistors and Diodes.Integrated CircuitsMicro ProcessorsArtificial Intelligence3.Programming SystemNo operating SystemNo Operating SystemOperating System UsedImproved Operating SystemHighly Sophisticated4.Language Used (Software)Machine (Binary) Language.Assembly Language, mnemonicsHigh Level Language, BASIC, FORTRAN, PASCAL, COBOL.4GL, Object Oriented Language Such as SQL. (For Data Base Access)Artificial Intelligence.5.SizeMuch heed Generated -Need AC.Heed Generated Need AC.Low Heed- Needless ACNo Heed - no A/CNothing else.6.Speed (Time for one shift operation)1000 ms(Milliseconds)30ns (Nanoseconds)5 ns (Nanoseconds)1 ns (Nanoseconds)0.03 nsVI. DEFINITION AND MEANINGS 1. CPU - The CPU is the control center for a computer. It guides, directs & governs its performance. It is the brain of the computer.2. Output Device- The devices which are used to display the data to the user either in the form of hard copy or soft copy are called output devices.3. Input Device- The input unit is formed by the input devices attached to the computer4. Memory- The working place in computer where all data is stored is called memory. There are small cells called bit. In these cell data is stored in the form of 0 & 1. Its unit is bytes. A memory cell may be defined as a device which can store a symbol selected from a set of symbols.5. Operating System- An operating system is required to manage the computer and enable it to communicate with peripherals such as monitor, keyboard, mouse, or printer; and to control the flow of commands and data to and from programs or applications.Chapter: 1 Computer & Computer Science Introduction:Computer science or computing science (abbreviated CS or CompSci) is the scientific and practical approach to computation and its applications. A computer scientist specializes in the theory of computation and the design of computational systems.II. Major Branches Of Computer Science:1. Software Development: 1. Software development(also known asapplication development,software design, designing software,software application development,enterprise application development, orplatform development)is the development of asoftwareproduct.2. Software development may include research, new development, prototyping, modification, reuse, re-engineering, maintenance, or any other activities that result in software products.3. Software can be developed for a variety of purposes, the three most common being to meet specific needs of a specific client/business (the case withcustom software), to meet a perceived need of some set of potentialusers(the case withcommercialandopen source software), or for personal use (e.g. a scientist may write software to automate a mundane task).Embedded software development, that is, the development of embedded softwaresuch as used for controlling consumer products, requires the development process to be integrated with the development of the controlled physical product.2. Computer Architecture1. Computer Architecture is the science and art of selecting and interconnecting hardware components to create computers that meet functional, performance and cost goals. Computer architecture is not about using computers to design buildings.2. Computer architects use computers to design new computers.3. Emulationsoftware can run programs written in a proposed instruction set. While the design is very easy to change at this stage,compilerdesigers often collaborate with the architects, suggesting improvements in the instruction set. 4. Modern emulators may measure time in clock cycles, estimate energy consumption in joules, and give realistic estimates of code size in bytes.5. These affect the convenience of the user, the life of a battery, and the size and expense of the computers largest physical part: its memory. That is, they help to estimate the value of a computer design.3. Artificial Intelligence1. It is the science and engineering of making intelligent machines, especially intelligent computer programs. It is related to the similar task of using computers to understand human intelligence, but AI does not have to confine itself to methods that are biologically observable.2. The branch ofcomputer scienceconcerned with makingcomputersbehave like humans. The term was coined in 1956 by John McCarthy at the Massachusetts Institute of Technology. Artificial intelligence includes games playing:programmingcomputers to play games such as chess and checkers expert systems:programming computers to make decisions in real-life situations (for example, some expert systems help doctors diagnose diseases based on symptoms)natural language:programming computers to understand natural humanlanguagesneural networks:Systemsthat simulate intelligence by attempting to reproduce the types of physical connections that occur in animal brains4. Robotics1. A reprogrammable, multifunctional manipulator designed to move material, parts, tools, or specialized devices through various programmed motions for the performance of a variety of tasks2. Robot was coined by Czech playwright Karl Capek in his play R.U.R (Rossums Universal Robots), which opened in Prague in 1921. Robota is the Czech word for forced labor.3. The term robotics was introduced by writer Isaac Asimov. In his science fiction bookI, Robot,published in 1950, he presented three laws of robotics:1. A robot may not injure a human being, or, through inaction, allow a human being to come to harm.2. A robot must obey the orders given it by human beings except where such orders would conflict with the First Law.3. A robot must protect its own existence as long as such protection does not conflict with the First or Second Law.5. Human-Computer Interaction1. Humancomputer Interaction (HCI) involves the study, planning, and design of the interaction between people (users) and computers2. It is often regarded as the intersection of computer science, behavioral sciences, design and several other fields of study.3. humancomputer interaction studies a human and a machine in conjunction, it draws from supporting knowledge on both the machine and the human side. 4. On the machine side, techniques in computer graphics, operating systems, programming languages, and development environments are relevant. 5. On the human side, communication theory, graphic and industrial design disciplines, linguistics, social sciences, cognitive psychology, and human factors such as computer user satisfaction are relevant.UNIT : 2 Computer Architecture Section A : Computer Hardware 1. Representing Information.(a) A Bit: the unit of information in a computer. Computers process electric currents (electrical events). The current is either on (=1) or off (=0) in a particular circuit at a particular time. This gives rise to thebinary systemfor storing information. Each transistor in a computers memory can hold onebitofinformation(either a 0 or a 1). (b) Basic Measures for Information Capacity The information capacity of a storage deviced is measured in multiples of bits. Bit: 0 or 1. Byte: 8 bits. Can store 28 = 256 numbers. Kilobyte: Kilo (thousand) + byte: 210 bytes = 1,024 bytes. Megabyte: Mega (million) + byte: 220 bytes = roughly a million bytes. Gigabyte: Giga (billion) + byte: 230 bytes = roughly a billion bytes. Terabyte: Tera (trillion) + byte: 240 bytes = roughly a trillion bytes. Petabyte: Peta (quadrillion) + byte: 250 bytes = roughly a quadrillion bytes = 1,000,000,000,000,000 bytes. (c) Information Information as we think of it is data withmeaning: text, pictures, sounds. Information as the computer knows it isbit strings: strings of bits (e.g. 10011101010). Information as we know it isencodedin a computer using bit strings. Anencodingis an agreed-upon standard that dictates the specifics of how the information is represented using 0s and 1s. Example: ASCII is a widely-used text encoding standard. Under this encoding, each letter & digit & punctuation mark is assigned an 8-bit code which represents it. (How many possible such codes are there?) Example codes in table below.LetterCorresponding Bit StringNumberCorresponding Bit StringPunctuation MarkCorresponding Bit StringA10000001001100000!01000001B1000001010110000101000010C10000011201000010#01000011 What bit string does the text A111 correspond to? Newer (more comprehensive) standard for text encoding: UNICODE.2. Inside the Case(a) The Motherboard Exercise: look inside your computer case and locate the motherboard. Make sure you are grounded when you do this (e.g. touch a metal chair leg), since static electricity can disrupt your computer. Removable componentsmean your system isupgradeable Empty expansion slotsmean your system isexpandable The most fundamental component on the motherboard is the CPU (the processor). This is the brain of the computer. Computer chips (semiconductors) are cut from silicon dies. Chips are the building blocks of computer functionality. Chips are packed with very small transistors. The circuitry within the chip is printed on a silicon wafer usingphotolithography. Moores Lawstates that the number of transistors that can be packed onto a chip doubles every 18 months while the price stayes the same. The following table illustrates this trend.YearNumber of Transistors on chip19614 (previously: vacuum tubes were used!)19712,300197930,00019977.5 x 1062000109(b) Memory, Buses and Cardso Memory located in the system unit: RAM (in RAM slots on motherboard), disk drives (connect to motherboard via thick grey cables = the system bus).o Expansion slots for various cards: video cards, sound cards, network cards, etc.3.The Computer Processor (CPU)(a) Processor Typeso Intel (and Clones) 90% share of processor market. Windows oriented (OS = Hardware-Software interface) AMD, Cyrix, DEC manufacture compatible CPUs. Examples: Intel Pentium 4, AMD Athlon K6 Thunderbirdo Motorola Apple Macintosh Example: Motorola 68000 family of processors More recent: PowerPC (joint Motorola/IBM venture) (b) Processor Speedso Every processor has asystem clock(a pulsing quartz crystal).o The clocks speed (incycles per second= Hz) determines how fast the microprocessor can process data and execute program instructions.o MHz = mega-hertz = million cycles/sec (e.g. 100 MHz, 700 MHz)o GHz = billions