Computer Introduction CS102 PDF

‫مقدمة فى الحاسبات‬ Computer Introduction CS102 Dr Ibrahim Selim FCAI University of Sadat City The main objective of this course is to provide students with a general introduction to the basics of computer sciences and its different fields. The course may cover topics like: D...

‫مقدمة فى الحاسبات‬ Computer Introduction CS102 Dr Ibrahim Selim FCAI University of Sadat City The main objective of this course is to provide students with a general introduction to the basics of computer sciences and its different fields. The course may cover topics like: Digital revolution, digital devices, personal computers, servers, mainframes, super computers, microcontrollers, representing numbers, text, and pictures, quantifying bits and bytes, programs and instruction sets, microprocessor basics, RAM, ROM, EEPROM, magnetic disk and tape storage, CD and DVD storage, solid state storage, storage wrap-up, display devices, printers, system software, application software, utilities and device drivers, popular applications, software copyrights and licenses, software updates, operating system activities, network classifications, network devices, clients, servers, and peers, wired networks, wireless networks, Internet services, fixed, portable, and mobile Internet access, Internet infrastructure, Internet protocols, addresses, and domains, hardware security, software security, Internet security, number systems. What Is A Computer? A computer is an electronic device, operating under the control of instructions stored in its own memory that can accept data (input), process the data according to specified rules, produce information (output), and store the information for future use A computer is an electronic device that manipulates information, or data. It has the ability to store, retrieve, and process data. You may already know that you can use a computer to type documents, send email, play games, and browse the Web. You can also use it to edit or create spreadsheets, presentations, and even videos  Definition of a computer  By definition, a computer is an electronic device that inputs data, processes data(converting it into information that is useful to people) outputs and stores information.  Computers are controlled by programmed instructions that transform the data into meaningful information.  Generally a Computer is a device that accepts input, processes it, stores data, and produces output. 4 The word computer is derived from the word compute. Compute means to calculate. The computer was originally defined as a super fast calculator. It had the capacity to solve complex arithmetic and scientific problems at very high speed. But nowadays in addition to handling complex arithmetic computations, computers perform many other tasks like accepting, sorting, selecting, moving, comparing various types of information. They also perform arithmetic and logical operations on alphabetic, numeric, and other types of information. This information provided by the user to the computer is data. The information in one form which is presented to the computer is the input information or input data. Information in another form is presented by the computer after performing a process on it. This information is the output information or output data. AS WE SAY THE COMPUTER WOR UNDER CONTROL Computers are controlled by programmed instructions that transform the data into meaningful information operating under the control of instructions stored in its own memory that can accept data (input), process the data according to specified rules The set of instructions given to the computer to perform various operations is called as the computer program. The process of converting the input data into the required output form with the help of the computer program is called as data processing. The computers are therefore also referred to as data processors. Therefore, a computer can now be defined as a fast and accurate data processing system that accepts data, performs various operations on the data, has the capability to store the data and produce the results based on detailed step by step instructions given to it. Types of Computers Types of Computers Types of Computer There are two bases on which we can define the types of computers. We will discuss the type of computers on the basis of size and data handling capabilities. We will discuss each type of computer in detail. Let’s see first what are the types of computers. Types of Computers 1. Analog computers: In analog computers, data is recognized as a continuous measurement of a physical property like voltage, speed, pressure etc. Readings on a dial or graphs are obtained as the output, ex. Voltage, temperature; pressure can be measured in this way. 2. Digital Computers: These are high speed electronic devices. These devices are programmable. They process data by way of mathematical calculations, comparison, sorting etc. They accept input and produce output as discrete signals representing high (on) or low (off) voltage state of electricity. Numbers, alphabets, symbols are all represented as a series of 1s and 0s.  Types of Computers On the basis of Computing Power & Size: Laptop / Palmtop Micro Computer / Desktop Mini Computer / Mainframe Super Computer Types of Computers Super Computer Mainframe computer Mini Computer Workstation Computer Personal Computer (PC) Server Computer Types of Computers Analog Computer Digital Computer Hybrid Computer Tablets and Smartphone  Types of Computers  Small Computers:  Microcomputers: are generally referred to as Personal Computers (PCs). They have Smallest memory and less power. They are widely used in day-to-day applications like office automation, and professional applications, ex. PC- AT, Pentium etc.  Notebook and Laptop Computers: These are portable in nature and are battery operated. Storage devices like CDs, floppies etc. and output devices like printers can be connected to these computers. Notebook computers are smaller in physical size than lap top computers. However, both have powerful processors, support graphics, and can accept mouse driven input. Microcomputer Notebook or Laptop Handheld Computer  Types of Computers  Handheld Computers: These types of computers are mainly used in applications like collection of field data. They are even smaller than the notebook computers.  Hybrid Computers: Hybrid Computers are a combination of Analog and Digital computers. They combine the speed of analog computers and accuracy of digital computers. They are mostly used in specialized applications where the input data is in an analog form i.e., measurement. This is converted into digital form for further processing. The computers accept data from sensors and produce output using conventional input/output devices.  Mini-Computers: Mini-computers are more powerful than the micro-computers. They have higher memory capacity and more storage capacity with higher speeds. These computers are mainly used in process control systems. They are mainly used in applications like payrolls, financial accounting, Computer aided design etc. ex. VAX, PDP-11  Types of Computers  Mainframe Computers: Main frame computers are very large computers which process data at very high speeds of the order of several million instructions per second. They can be linked into a network with smaller computers, micro-computers and with each other. They are typically used in large organizations, government departments etc. ex. IBM4381, CDC  Super Computers: A super-computer is the fastest, most powerful and most expensive computer which is used for complex tasks that require a lot of computational power. Super computers have multiple processors which process multiple instructions at the same time. This is known as parallel processing. These computers are widely used in very advanced applications like weather forecasting, processing geological data etc. ex. CRAY-2, NEC - 500, PARAM. What Does A Computer Do? Computers can perform four general operations, which comprise the information processing cycle. Input Process Output Storage 17 Data and Information All computer processing requires data, which is a collection of raw facts, figures and symbols, such as numbers, words, images, video and sound, given to the computer during the input phase. Computers manipulate data to create information. Information is data that is organized, meaningful, and useful. During the output Phase, the information that has been created is put into some form, such as a printed report. The information can also be put in computer storage for future use. 18 The activity of processing data using a computer is called data processing Data Capture Data Manipulate Data Output Results Information Data is raw material used as input and information is processed data obtained as output of data processing How Does a Computer Know what to do? It must be given a detailed list of instructions, called a compute program or software, that tells it exactly what to do. Before processing a specific job, the computer program corresponding to that job must be stored in memory. Once the program is stored in memory the compute can start the operation by executing the program instructions one after the other. Why Is A Computer So Powerful? The ability to perform the information processing cycle with amazing speed. Reliability (low failure rate). Accuracy. Ability to store huge amounts of data and information. Ability to communicate with other computers. Components Of A Computer  Parts of a Computer System  Computer systems have four parts  Hardware  Software  Data  User (people) 23 Introduction to Computers  Parts of a Computer System  Computer hardware:  A computer's hardware consists of electronic devices; the parts you can see and touch.  Inotherwords these are tangible parts of a computer.  The term "device" refers to any piece of hardware used by the computer, such as a keyboard, monitor, modem, mouse, etc.  These are mechanical devices that make up the computer. 24 Introduction to Computers  Computer Hardware Components  Display Device (Monitor or LCD screen)  System Unit  Floppy disk drive  CD ROM drive  Hard disk drive  Keyboard  Mouse 25 Introduction to Computers  Other hardware components  DVD drive (Digital Versatile Disk)  CD writer (Compact disk)  Sound card and speakers  Modem (Modulate and Demodulate)  Printers. 26 Introduction to Computers  Peripherals  A peripheral device designates equipment that might be added to a computer system to enhance its functionality.  Examples:  Printer  Digital camera  Scanner  Joystick 27 Introduction to Computers Components of A Computer System  The hardware is the machinery itself. It is made up of the physical parts or devices of the computer system like the electronic Integrated Circuits (ICs), magnetic storage media and other mechanical devices like input devices, output devices etc. All these various hardware are linked together to form an effective functional unit.  The computer hardware itself is not capable of doing anything on its own. It must be given explicit instructions to perform the specific task. The computer program is the one which controls the processing activities of the computer. The computer thus functions according to the instructions written in the program.  Software mainly consists of these computer programs, procedures and other documentation used in the operation of a computer system.  Software is a collection of programs which utilize and enhance the capability of the hardware. Computer hardware  Computer hardware is made up of the physical parts of the computer system like the electronic ICs, magnetic storage media and the mechanical devices.  The devices which are a means of communication between the computer and the outside world are called as peripheral devices.  Those peripheral devices which supply information i.e. data and programs from the outside world to the computer are the input devices.  Those peripheral devices which give information from the computer to the user or store them in secondary storage devices, like floppy disks or tapes for future use are called output devices.  What Are The Primary Components Of A Computer ? Input devices. Central Processing Unit (containing the control unit and the arithmetic/logic unit). Memory. Output devices. Storage devices. Devices that comprise a computer system Monitor Speaker (output) (output) System unit (processor, memory…) Printer (output) Storage devices (CD-RW, Floppy, Hard disk, zip,…) Mouse (input) Scanner Keyboard (input) (input) 31 Components of A Computer System The basic parts of computer system are:  Input Unit  Storage Unit  Primary Storage  Secondary Storage  The Central Processing Unit  The Control Unit  The Arithmetic Logic Unit  Output Unit Components of A Computer System Storage Unit Secondary Storage Program Information Input Output and (Results) Unit Unit Data Primary Storage Control Unit Indicates flow of instructions and data Arithmetic Indicates the control Logic Unit exercised by the control unit Central Processing Unit (CPU) Components of A Computer System Input Unit: An input unit of a computer system performs the following functions: 1. It accepts (or reads) instructions and data from outside world. 2. It converts these instructions and data in computer acceptable form. 3. It supplies the converted instructions and data to the computer system for further processing. Components of A Computer System Storage Unit: The storage unit of a computer system holds (or stores) the following : 1. Data and instructions required for processing (received from input devices). 2. Intermediate results of processing. 3. Final results of processing, before they are released to an output device. Components of A Computer System (Cont.) Two Types of Storage:  Primary Storage  Used to hold running program instructions.  Used to hold data, intermediate results, and results of ongoing processing of job(s).  Fast in operation.  Small Capacity.  Expensive.  Volatile (looses data on power dissipation). Components of A Computer System Two Types of Storage:  Secondary Storage  Used to hold stored program instructions.  Used to hold data and information of stored jobs.  Slower than primary storage.  Large Capacity.  Lot cheaper that primary storage.  Retains data even without power. The Central processing Unit The central processing unit (CPU) contains electronic circuits that cause processing to occur. The CPU interprets instructions to the computer, performs the logical and arithmetic processing operations, and causes the input and output operations to occur. It is considered the “brain” of the computer. 38 Components of A Computer System Central Processing Unit (CPU)  It is the brain of a computer system.  It is responsible for controlling the operations of all other units of a computer system. Arithmetic Central Logic Unit Control Unit = Processing + (ALU) (CU) Unit (CPU)  Control Unit (CU) of a computer system manages and coordinates the operations of all other components of the computer system.  Arithmetic Logic Unit (ALU): is the place where the actual executions of instructions takes place during processing operation. Components of A Computer System Output Unit: An output unit of a computer system performs the following functions: 1. It accepts the results produced by the computer, which are in coded form and hence, cannot be easily understood by us. 2. It converts these coded results to human acceptable (readable) form. 3. It supplies the converted results to outside world. Components of A Computer System The System Concept: A system has following three characteristics: 1. A system has more than one element. 2. All elements of a system are logically related. 3. All elements of a system are controlled in a manner to achieve the system goal. A computer is a system as it comprises of integrated components (Input Unit, Output Unit, Storage Unit, and CPU) that work together to perform the steps called for in the executing program. Input Devices 1. Punch Cards :  Data is recorded onto punch cards or punch tapes using standard codes, like the Hollerith code.  The pattern of these holes is interpreted by a card reader device and converted into machine readable form.  punch card machine is used to transcribe the data onto the card. Input Devices  Advantage of punch card  Cheaper Reliable  Disadvantage of punch card Cannot be reused  Have to be handled and stored carefully  Even if a single card is misplaced or the arrangement of the cards gets disturbed it becomes very difficult to rearrange them and to detect there problem.  Punched cards require large storage space since they cannot be folded. Some of the popular input devices are: 1. Keyboard 2. Mouse 3. Scanner 4. Joystick 5. Light Pen Some of the popular input devices are: 6. Digitizer 7. Microphone 8. Magnetic Ink Character Recognition (MICR) 9. Optical Character Reader (OCR) 10. Digital Camera Some of the popular input devices are: 11. Paddle 12. Steering Wheel 13. Gesture recognition devices 14. Light Gun 15. Touch Pad Some of the popular input devices are: 16. Remote 17. Touch screen 18. VR 19. Webcam 20. Biometric Devices Input Devices 2. Keyboard  The keyboard is one of the most commonly used input device. The computer keyboard is similar to a typewriter keyboard.  The keyboard has keys made up of letters, numbers, symbols and special function keys. The most commonly used input device is the keyboard on which data is entered by manually keying in or typing certain keys. A keyboard typically has 101 or 105 keys. The Keyboard 49 Input Devices  The keys on the keyboard include : A-Z : Used to enter alphabets 0-9 : Used to enter numbers Up, Down, Left, Right(Arrow Keyes): To Move the cursor in the specified direction F1-F12 : Special Function Keys PgUp/PgDn : To move cursor up or down by one page enter: To move cursor to a new line Shift : A Special key To Select the other option shown normal character on the same key Num Lock : Activates the keypad on the right side of the keyboard. In the normal mode this numeric pad works as per the function written below the number on the key Is a pointing device which is used to control the movement of a mouse pointer on the screen to make selections from the screen. A mouse has one to five buttons. The bottom of the mouse is flat and contains a mechanism that detects movement of the mouse. The Mouse 51 Input Devices 3. Mouse  The mouse is a pointing device.  It is used to control and manipulate cursor movement on the monitor.  It usually has three or four buttons on it and a roller ball which signals the movements made by the mouse on a flat surface.  These movements are transferred to the system. Input Devices 4. Light Pen  The light pen is a picking dev ice.  The light pen contains a photocell placed in a small tube.  This photo- cell detects the presence of light on the CRT (monitor).  The tip of the pen is moved on the surface of the screen to write or sketch data. The light pen is especially useful in Computer Aided Design (CAD) applications. Input Devices 5. Touch screen:  Input is registered when a finger or any other object comes in contact with the plate.  There are two types of touch panels: 1.Optical touch panels 2. Electric touch panels Input Devices 6. Scanner :  Scanner can directly enter text and images into the computer memory.  Therefore, the duplication work of entering data is eliminated and this also results in increased accuracy.  The speed of data entry also increases. There are two types of scanners : 1. Optical Scanners 2. Magnetic Ink Character Recognition devices Magnetic Scanner Optical Scanner Output Devices 1. Printers:  A printer produces the output from the computer on the paper.  It is the most used output device.  The printers produce a hard copy i.e. a permanent copy of the results which can be stored and read later.  Printers are classified as : 1. Impact Printer are similar to typewriters E.g. Dot matrix printers, line printers. 2. Non Impact Printer E.g. Laser printers, DeskJet printers.  Output Devices 2. Plotter : A plotter is an output device used in applications where printouts of graphs and drawings are required.  Plotters are of two types : 1) Flat bed i.e. X-Y plotter:  This plotter plots on a paper which is fixed on a rectangular flatbed table.  One recording pen moves in the x direction and one in the y direction to plot on the paper.  Color plotting is also possible by using pens of different colors. 2) Drum Plotter: In this plotter the paper on which the output is to be obtained, is placed over a drum. The drum rotates back and forth to produce motion. Output Devices 3. Screen The most common flat panel display is the Liquid Crystal Display (LCD). Output Devices 4.Computer Output Microfilm (COM):  This technology is used to record the computer output as microscopic, filmed images.  Information is recorded on a roll of microfilm.  A microfilm recorder displays the information onto a screen. Output Devices Output devices make the information resulting from the processing available for use. The two output devices more commonly used are the printer and the computer screen. The printer produces a hard copy of your output, and the computer screen produces a soft copy of your output. 60 Storage Devices Auxiliary storage devices are used to store data when they are not being used in memory. The most common types of auxiliary storage used on personal computers are floppy disks, hard disks and CD-ROM drives. 61 Floppy Disks A floppy disk is a portable, inexpensive storage medium that consists of a thin, circular, flexible plastic disk with a magnetic coating enclosed in a square-shaped plastic shell. 62  The disk’s storage locations are divided into pie- shaped sections called sectors. A sectors is capable of holding 512 bytes of data. A typical floppy stores data on both sides and has 80 tracks on each side with 18 sectors per track. 64 Hard Disks Another form of auxiliary storage is a hard disk. A hard disk consists of one or more rigid metal plates coated with a metal oxide material that allows data to be magnetically recorded on the surface of the platters. The hard disk platters spin at a high rate of speed, typically 5400 to 7200 revolutions per minute (RPM). Storage capacites of hard disks for personal computers range from 10 GB to 120 GB (one billion bytes are called a gigabyte). 65 Compact Discs A compact disk (CD), also called an optical disc, is a flat round, portable storage medium that is usually 4.75 inch in diameter. A CD-ROM (read only memory), is a compact disc that used the same laser technology as audio CDs for recording music. In addition it can contain other types of data such as text, graphics, and video. The capacity of a CD-ROM is 650 MB of data. 66 67