Unit 1 Introduction IOCS.pdf

Introduction to Computer & its Architecture 1  Definition of a Computer a general purpose, programmable, information processor with input and output 2  Definition of a Computer A comput...

Introduction to Computer & its Architecture 1  Definition of a Computer a general purpose, programmable, information processor with input and output 2  Definition of a Computer A computer is an electronic device that performs mathematical and non-mathematical operations with the help of instructions to process the information in order to achieve desired results. 3  Characteristics of Computer 1. Speed 2. Accuracy 3. Reliability 4. Diligence 5. Versatility 6. Storage Capability 7. No I.Q 8. No Feelings 4...Characteristics of Computer... Speed... Process data at an extremely fast rate Work done as enormous speed as compare to human beings Speed of Computer is calculated in MHz(MegaHertz) i.e. one million instructions per second. 5...Characteristics of Computer... Accuracy... Work with the highest Accuracy Accuracy depends upon the "Design of Computer“ i.e. instructions and the type of machine being used Human Errors are like wrong command, inaccurate data input etc GIGO → Garbage In Garbage Out Error Detecting Techniques 6...Characteristics of Computer... Reliability… Measurement of performance of Computer Perform operation without any failure At hardware level, it does not require any human intervention between its processing operations. 7...Characteristics of Computer... Diligence... Free from "Tiredness" Free from Lack of "Concentration" 8...Characteristics of Computer... Versatility... Can perform all kind of job simultaneously Can do diverse nature of works like calculations, graphics work, searching etc at the same time 9...Characteristics of Computer... Storage Capability... Unlike human being Computer can store huge amount of data Loss or Deletion of data is done by User The computer memory is small and it can hold only a certain amount of information, therefore the data is stored on storage devices such as magnetic tape or disk. 10...Characteristics of Computer... No IQ... Not a thinking machine Not Intelligent Never does a task by it’s own Follow Human Instructions Only perform what it is programmed to do : nothing more & nothing less 11...Characteristics of Computer... No Feeling... No taste No emotions No knowledge 12 Generation of Computer 13  Generations of Computer ❖ ‘Generation’ : stage of technological development or innovation. ❖According to the kind of ‘processor’ installed in a machine, there are five generations of computer The First generation The Second Generation The Third Generation The Fourth Generation The Fifth Generation 14  The First Generation Magnetic drums 1940-1956 memory Vacuum Tube Input – Heat – Punched cards – Burnout Output Machine language (0/1) – Printout Characteristics of 1st Generation Computers ▪ Computers big and clumsy ▪ Electricity consumption is high ▪ Hardware failure occurred regularly - computers not very reliable ▪ Large air conditioners was necessary because the computers generated heat ▪ non-portable, lacked in versatility & speed ▪ Batch processing (one problem at a time) 15  vacuum tube ENIAC - first generation computer 1940-1956 16  The Second Generation  1956-1963  Storage › Magnetic cores – primary  Transistor memory › Smaller › Magnetic disks – secondary › Less heat memory › Faster  Programming languages › More reliable › Assembly language (mnemonics) › FORTRAN (1954) › COBOL(1959) › Input: Punched card › Output: Printout Used primarily by business, university, government 17  The Second Generation Computers became smaller Generate less heat Electricity consumption lower More reliable - less prone to hardware failure Better portability Assembly language used to program computers – programming became more time efficient 18  transistor second generation computer 1956-1963 19 1 = 40 20  The Third Generation  1964- Early 1970  Integrated Circuit › Electronic circuit on 1. Computers smaller, small silicon chip faster and more › Transistors and reliable resistors fabricated on 2. Power consumption it lower › Reliability › Compactness 3. High-level › Low cost languages appeared › Inexpensive – mass- produced 21  integrated circuit third generation computer 1964-1970 22  The Third Generation Easily portable and more reliable Instead of punched cards and printout, for interaction with computer keyboard and monitors were used Size of computer was smaller compared to previous generation Commercial production become easier and cheaper 23  The Fourth Generation Early 1970s – Till Date Integrated circuits, smaller and Microprocessor faster › General-purpose Micro computer series such as processor on a chip IBM and APPLE developed › All the components of Portable computers developed a computer are on a Great development in data chip communication Explosive growth Different types of secondary › Digital watches memory with high storage › Pocket calculators capacity and fast access › Personal computers developed › Cars › Copy machines › Television sets 24  The Fourth Generation Large Scale Integration (LSI): thousand of transistors are constructed on small chip Very Large Scale Integration (VLSI): hundreds of thousands of components on single chip Ultra – Large Scale Integration (ULSI): millions of components on single chip 25  1 1000 26  The Fourth Generation Powerful, compact, reliable and affordable – personal computer (PC) Faster random access main memory Hard disk became economical, smaller and bigger in capacity Cheapest among all the other generation Hardware failure is negligible, so minimum maintenance required Generate negligible amount of heat, hence do not required air conditioning Interconnection with computer leads to better resource sharing and communication, also developed pointing devices Disadvantage: Required complex and sophisticated technology for manufacturing of CPU and the other components. 27  The Fifth Generation Still in development stage Use Super Large Scale Integrated (SLSI) chips Artificial Intelligence Knowledge based problem solving techniques Input and Output: Graphical image and natural language Perform multiple simultaneous instructions 28 Classification of Computers 29 I. ACCORDING TO FUNCTION OR PURPOSE 1. SPECIAL PURPOSE COMPUTER is a computer that is designed to operate on a restricted class of problems. It is dedicated to one function only. Examples: ATM Machine, Washing Machine, Cash Registers etc. 2. GENERAL PURPOSE COMPUTER is a computer that can be programmed to do many different kinds of tasks, rather than one that is limited by design to a specific task. Most computers are general purpose, and can have software installed for many different uses. Lack in speed and efficiency http://t0.gstatic.com/images?q=tbn:SVq8wDzMz9MHhM:http://talkinstuff.files.wordpress.com/2009/05/laptop.jpg Examples: Desktop computer, Laptop Computer 30 II. ACCORDING TO THE TYPE OF DATA HANDLED 1. ANALOG COMPUTERS were the first type to be produced. They measure continuous variable, physical quantities such as electrical potential, fluid pressure, mechanical motion etc. Do not deal with numbers. Measure continuous physical magnitudes.(temperature, pressure) Give approximate results, very fast and less accurate Examples: Speedometer of a Car, Gasoline Pump 31 2. DIGITAL COMPUTERS. Handle information that can be counted. Uses digital circuits and are designed to operate on two states, namely bits 0 and 1. These bits can be combined to denote information such as numbers, letters, graphics, images and program instructions. Digital computers are suitable for complex computation and have higher processing speeds. They are programmable. Very accurate Examples: Desktop Computers, Laptop, smart phones, etc.. 32 3. HYBRID COMPUTERS It is a combination of both analog and digital computer. Can handle both analog and digital data. A hybrid computer combines the best characteristics of both the analog and digital computer. It can accept data in both analog and digital form Application areas such as manufacturing, transportation, power systems and others 33  III. ACCORDING TO SIZE & PROCESSING POWERS 1. MICROCOMPUTERS A microcomputer is a small, low cost computer with a microprocessor as its central processing unit. They are physically small compared to mainframe and minicomputers. Many microcomputers (when equipped with a keyboard and screen for input and output) are also personal computers (in the generic sense). Classification within this category includes: ▪ Desktop ▪ Workstations ▪ Laptop ▪ Handheld ▪ Embedded computers 34 ❑ DESKTOP COMPUTERS are the most common type of personal computer and are designed to fit conveniently on the surface of a desk or workspace. Desktop computers have separate display screens, keyboards, internal hard disk storage and other peripheral devices. ❑ Workstation is simply a desktop computer that has a more powerful processor, additional memory and enhanced capabilities for performing a special group of task, such as 3D Graphics or game development. 35 ❑ LAPTOP COMPUTER also called a notebook, is a personal computer for mobile use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device (touchpad or trackpad) and speakers into a single unit. Powered via an AC adapter, and can be used away from an outlet using a rechargeable battery. Classification: ✓ Desktop replacements ✓ Subnotebook ✓ Notebook ✓ Rugged ✓ Tablet PC 36 ❑ Handheld Computer is a small, hand-held computing device, typically having a display screen with touch input and/or a small keyboard. Typical handhelds: Information appliance Smart phone/Mobile Phone Personal digital assistant (PDA) Personal Communicator 37 ❑ EMBEDDED COMPUTERS ✓ “Computers on a chip”. A microprocessor or a microcontroller, which is programmed to perform a small number of tasks. ✓ are the “brains” behind many everyday mechanisms, such as wireless devices, cars, climate control systems, traffic signals, and washing machines, ticket machines at the subway, cameras, airplanes, cars, sewing machines, clocks, etc. ✓ The software written for many embedded systems is called firmware. Firmware is software that is embedded in hardware devices, e.g. in one or more ROM or Flash memory IC chips. 38 2. MINI COMPUTERS. Minicomputers are mid-range computers whose size, speed and capabilities lie somewhere, between those of a mainframe and a microcomputer. A minicomputer is a class of multi-user computers that lies in the middle range of the computing spectrum, in between the largest multi-user systems (mainframe computers) and the smallest single- user systems (microcomputers or personal computers). It is capable of supporting 4 to 200 users simultaneously. 39 3. MAINFRAME COMPUTERS ▪ Powerful computers used mainly by large organizations for critical applications, typically bulk data processing such as online transaction processing system, extensive data storage and retrieval. ▪ Most of the mainframe computers have the capacities to host multiple operating systems and can handle hundreds of users (can serve up to 50,000 users simultaneously) 40 4. SUPER COMPUTERS ▪ Fastest, costliest and most powerful. Generally operate at 4 to 10 times faster than the mainframe. ▪ designed to work on a single problem at a time. ▪ Supercomputers are used for highly calculation-intensive tasks such as problems including quantum physics, weather forecasting, climate research, molecular modeling , physical simulations, aircraft and spacecraft designing, encrypting & decoding sensitive intelligence information Deep Blue computer play a chess game against Garry Kasparov in 1997, it is an IBM supercomputer that uses scalable parallel processing to solve complex problems. Deep Blue uses 256 processors working together to calculate between 50 and 100 billion chess moves in under three minutes. 41 Applications of COMPUTER 42  Uses of computer in e - commerce ❖ electronic mail ❖ video conferencing ❖ electronic shopping ❖ electronic banking 43  Education o Better study moods o most understandable and easier o internet facility provides a lot of information from any corner of the world 44  Medicine & Health care ❑Patient monitoring ❑ patient records ❑ diagnosis ❑ hospital administration ❑ medical history records ❑ life support system 45 Entertainment 46 Engineering/Architecture/Manufacture 47  Computer System Central Processing Unit ALU Control Unit Input Output Registers CPU: This unit performs processing of instructions and data inside the computer Input Unit: accepts instructions and data Output Unit: communicates the results to the user  Central Processing Unit The CPU or microprocessor is referred as the ‘brain’ of a computer system. It is a silicon chip that contains millions of tiny electrical components. CPU controls all external and internal devices and performs arithmetic and logic operations. It interprets, coordinates the operations and supervises the instructions. Basic functions of CPU are: 1. Carrying out arithmetic and logic functions and sends the result to the output unit. 2. Controlling the use of memory to store data and instructions. 3. Controlling the sequence of operations. 4. Controlling all parts of the computer system.  Central Processing Unit How do computers represent data? CPU works with only binary data. Recognize only two discrete states: on or off Use a binary system to recognize two state. Use Number system with two unique digits: 0 and 1, called bits (short for binary digits) 8 Interaction between functional blocks CPU: Processor Interprets and carries Registers out basic instructions that operate a computer Control Control Unit Arithmetic Arithmetic Unit Logic Unit Logic (ALU) Unit Also called the processor (ALU) Instructions Data Control unit directs and Information coordinates operations in computer Input Output Devices Data Memory Information Devices Arithmetic logic unit Instructions (ALU) performs Data arithmetic, comparison, Information and logical operations Storage Devices Interaction between functional blocks The set of wires used for interconnection is known as system bus. System bus is used to transmit data from one unit to another. System bus is collection of wires through which data is transmitted from one unit to another (CPU, Memory and I/O devices) System bus has certain size or width called data path which is measured in bits. Interaction between functional blocks System bus is further divided into three logical units: address bus, data bus and control bus Data Bus: It transfers actual data or instructions between the processor, memory and I/O devices. Address Bus: It informs the CPU about the location of the data residing in the memory. Before data or instructions can be written into or read from memory by cpu or I/O sections, address must be transmitted to memory over the address bus. Control Bus: It is responsible for making CPU, memory and I/O devices work together as a functional system, carrying signals to instruct other units. Status ready/ not ready for read/write of other device Interaction between functional blocks Processor and memory units holds a bidirectional relationship with the control and data bus. In case of address bus, the communications with processors and memory is unidirectional. The processor provides location of data (stored in memory), to be fetched from memory, to the address bus and data bus carries the required data to processor. What is a register? Temporary high-speed storage area that holds data and instructions They hold the information that the CPU is currently working on so they also known as CPU’s working memory. Stores location from where instruction was Stores fetched Stores data instruction while it while ALU is being decoded computes it Stores results of calculation  Registers Register Name Function Program Counter (PC) A Program counter keeps track of next instructions to be executed. Instruction Register (IR) An IR holds the instructions to be decoded by the control unit. Memory Address Register (MAR) MAR holds address of the next location in memory to be accessed. Memory Buffer Register (MBR) MBR is used for storing data either coming to the CPU or data being transferred by the CPU. Accumulator (ACC) An accumulator is general purpose register Used for storing temporary results and results produced by arithmetic logic unit. Data Register (DR) A Data register is used for storing the operands and other data.  Arithmetic / Logic Unit ALU Performs arithmetic operations Performs logical operations Arithmetic Operations + Addition Subtraction - Multiplication Division / *  Logical Operations Evaluates conditions NOT Makes comparisons Can compare AND – Numbers OR – Letters – Special characters = > < >=