Useful for Grade IX Computer Fundamental Computer Engineering

1.1 Introduction to Computer

Key Terms to remember

• Computer: an electronic machine that takes input from the user and stores processes it to generate the output in the form of useful information to the user.
•  Data: the raw details that need to be processed to generate some useful information.
• Program: the set of instructions that can be executed by the computer in sequential or non-sequential manner.
• Information: Processed data useful for the user.
• CPU: the processor of the computer that is responsible for controlling and executing instructions.
• Monitor: A screen, which displays the information in the visual form, after receiving the video signals from the computer.
• Transistor: A semiconductor device that is used to increase the power of the incoming signals by preserving the shape of the original signal.
• Microprocessor: An integrated circuit that contains the entire central processing unit of a computer on a single chip.
• Vacuum Tube: An electron tube from which all or most of the gas has been removed, permitting electrons to move with low interaction with any remaining gas molecules.
• LSI: Large Scale Integration
• VLSI: Very Large Scale Integration refers to an IC or technology with many devices on one chip.
• ULSI: Ultra Large Scale Integration.
• ICs: The circuit that combines various electronic components, such as transistors, resistors, capacitors, etc onto single small silicon chip.
• Analog Computer: A type of computer which represents data in the form of continuous signals.
• Digital Computer: A type of computer that stores and processes data in digital form and is also known as the digital information processing system.
• Hybrid Computer: A combination of analog computer and digital computer because it encompasses the best features of both these computers.
• Microcomputer: A small digital computer that is designed to be used by individuals.
• Super Computer: The fastest type of computer that can perform complex operations at a very high speed.
• Mainframe Computer: A very large computer that is employed by large business organizations for handling major application, such as financial transaction processing applications and ERP.
• Hardware: A group of electronic devices that make up a computer. They are used for performing tasks, such as entering the data, processing of data and then displaying the output to the users.
• Software: The programs and instructions that help the computer in carrying out their processing.
• Application Software: The programs, which are designed to perform a specific task for the user.
• System Software: The programs, which are designed to control the different operations of the computer systems

 Unit 2: Computer Software

Key Terms to Remember

• Hardware: Hardware refers to various electronic and mechanical devices, which are responsible for performing various operations, such as storing data into the storage devices, transferring data through buses and cables, etc.
• Software: Software is a set of programs and procedures containing a number of instructions for processing the data.
• Application Software: Application software is the software that enables the end user to perform various tasks, such as creating documents, preparing presentations, creating database, developing graphics and images, etc.
• Operating System: Operating system is a set of various small system software which controls the execution of various sub process in a computer system.
• Utility Programs: Utility program refers to a small program that helps perform utility tasks in a computer system.
• Device Driver: Device driver is special software that enables a hardware device such as keyboard, monitor and printer to perform an operation according to the command given by the end users.
• Editor: Editor is a program that allows the user to write and exit text in the computer system.
• Spreadsheet: Spreadsheet is a computer program that enables the user to maintain a worksheet in which information is stored in different cells.
• Hierarchy chart: Hierarchy chart is a design tool that shows the top-down design of  a problem solution.
• Pseudo code: Pseudo code is a set of instructions that describes logic of a solution.
• Algorithm: Algorithm is a sequential structure of steps, which are performed to solve a particular problem.
• Flowchart: Flow chart is a pictorial representation of a process, which describes the sequence and flow of the control and information in a process.
• Language Translator: It is a program that converts a high-level language program into a low-level language program. Compilers, Assemblers and Interpreters are examples of language translator.
• Compiler: It is a program that translates a high-level program into a machine language program.

Unit 3: Operating System Overview

Key terms to remember

• Operating System: It is a system software that manages the hardware and other resources of a computer system and enables effective user interaction.
• Process Management: Process management involves the execution of various tasks, such as creation of processes, scheduling of processes, management of deadlocks and termination of processes.
• Process States: Process state is the condition of a process at a particular instant of time.
• Process Control Block: PCB is a data structure associated with a process that provides complete information about the process.
• Process scheduling: Process scheduling is a task performed by an operating system for deciding the priority in which the processes are allocated the CPU time for their execution.
• Process Synchronization: process synchronization is the task of synchronizing the execution of processes in such a manner that no two processes have access to the same shared data of resource.
• Interprocess Communication: Interprocess communication is the method of communication between processes through which processes interact with each other for gaining access to shared data and resources.
• Deadlock: It is a condition that occurs when multiple processes wait for each other to free up resources and as a result all the processes remain halted.
• Memory Management: Memory management function of an operating system helps in allocating the main memory space to the processes and their data at the time of their execution.
• File management: File management is defined as the process of manipulating files in a computer system.
• Security Management: Security management function of an operating system helps in implementing mechanisms that secure and protect the computer system internally as well as externally.
• Batch processing Operating system: This operating system processes the jobs by organizing them in groups called batches. It processes only one job at a time.
• Multi-User Operating System: It allows multiple users to work simultaneously on the same computer system.
• Multitasking Operating system: It allows a user to carry out multiple tasks at the same time on a single computer system.
• Real-time operating system: It is used for processing critical applications that are required to be executed within a specific period of time.
• Multiprocessor operating system: It allows the use of multiple CPUs in a computer system for executing multiple processes at the same time.
• Embedded operating system: It is installed on an embedded computer system, which is primarily used for performing computational tasks in electronic devices.
• User Interface: UI facilitates communication between an application and its users by acting as an intermediary between them.
• Graphical User Interface: GUI is a type of UI that enables the users to interact with the operating system by means of point-and-click operations.
• Command Line Interface: CLI is a type of UI that enables the users to interact with the operating system by issuing some specific commands.
• Kernel: Kernel is the central part of the ULIX operating system that manages and controls the communication between the various hardware and software components.
• Shell: Shell is the user interface of the UNIX operating system that acts as an intermediary between the user and the kernel of the operating system.

Unit 4: Memory System Overview

Key Terms to Remember

• Primary Memory: It refers to the storage locations that are used to hold the programs and data temporarily in a computer system. The primary memory is usually known as memory.
• Secondary Memory: It refers to the storage locations that are used to hold the data and programs permanently.
• Internal process Memory: This type of memory is placed either inside or near the CPU. It is generally connected to the CPU through special fast bus. Internal process memory usually includes the cache memory and the resisters.
• RAM: it is a volatile memory in which data can be accessed in random fashion. Since it is a volatile memory, the data and programs stored in it will be lost when the power is switched off.
• ROM: It is a non-volatile memory that is used to store data permanently.
• Byte: It is the smallest addressable unit of memory.
• Static RAM: it is a type of RAM in which data is stored till the power of the computer system is switched on. Static RAM used a number of transistors to store a single bit of digital bit of digital information.
• Dynamic Ram: It is the Ram in which data is stored in a storage cell consisting of a transistor and capacitor.
• Programmable ROM: It is a memory chip on which the write operation of data can be performed only once.
• Erasable PROM:       It is a type of ROM in which data can be erased or destroyed using ultraviolet light.
• Electrically Erasable PROM: It is a type of ROM in which data can be erased or destroyed by exposing it to an electric charge, it has the ability to retain the data store in it, even if the power of the computer system is switched off.
• Flash ROM: It is a type of EEPROM that stores the information using floating-gate transistors.
• Magnetic Storage System: These are the storage systems that store the data on a magnetized medium with the help of magnetized particles.
• Magnetic disk: it is a flat disk that is covered with magnetic coating for holding information.
• Magnetic Tapes: These are the magnetic-coated plastic tapes, which are used for storing data and audio or video files.
• Optical Storage System: It uses the laser light as the optical medium to retrieve as well as record data.
• Magneto Optical (MO) storage System: These are the storage systems that include the features of both magnetic and optical storage system.

Unit 5: Components of Computer System

Key terms to Remember

• Input devices: It is an electromechanical device that is generally used for entering information into a computer system.
• Keyboard: It is a computer input device consisting of keys or buttons arranged in the similar fashion as they are arranged in a typewriter.
• Pointing Devices: These are the input devices used for moving the cursor to a particular location to point an object on the screen.
• Mouse: it is a pointing device that basically controls the two-dimensional movement of the cursor on the displayed screen.
• Track Ball:  It is a pointing device consisting of a socket containing the bal that can be rolled manually to move the cursor on the screen.
• Light pen: it is a pointing device containing the light-sensitive element, which is used for selecting the objects displayed on the screen.
• Joystick:  it is a pointing device that consists of one or more buttons and stick that controls the movement of the cursor on the screen.
• Touch screen: It is a pointing device that enables the users to enter data such as text, pictures and images by directly touching the screen.
• Scanning devices: These are the input devices that electronically capture text and images and convert them into computer readable form.
• Hand-held scanner: It is a scanning device used for digitizing the images into nit map.
• Flatbed scanner: It is a scanning device that consists of a flat surface composing of glass pane on which the documents are kept for scanning.
• Drum scanner: It is a scanning device consisting of a large drum that is used for scanning the documents.
• Slide Scanner: It is a scanning device used for scanning slides as well as film negatives.
• OCR device:  These devices scan a document by recognizing its individual characters optically and converting it into the editable form.
• OMR device: These are input devices are used for electronically recognizing the characters written in the marked fields only.
• MICR devices: These are input devices used for recognizing the characters written with the help of magnetic ink.
• Bar Code Reader: It is a scanning device used to read bar codes labeled on different items.
• Digital Camera: It is a hand held electronic device that is capable of capturing videos as well as graphical images electronically.
• Video Camera: These are the digital cameras that capture an image by converting it into horizontal lines and then scanning each line from top to bottom.
• Compact digital cameras: These are the small-sized digital cameras that lack some of the advanced image capturing features.
• Light-scan cameras: These cameras consist of an array of image sensors and are used to capture an image in the form of lines. After capturing an image, it scans the image line by line.
• Digital single-lens reflex cameras: These cameras consist of a mirror and a pent prism used for capturing the image digitally.
• Voice recognition system: It is a system that recognizes the voice of an individual an converts it into the machine readable code.
• Data acquisition sensors: These are the devices used for detecting and measuring the different physical quantities and converting them into electrical signals.
• Media Input devices: These are the input devices used in media for communicating with the mass audiences.
• Microphone: It is a media input device that converts the sound waves into the electrical signals with the help of sensors.
• Webcam: It is a media input device that is attached with the computer for recording videos as well as images.
• Graphics tablet: It is a media input device that help-s a user to enter pictorial information into the computer system.
• Monitor: Monitor is the most commonly used output device, which displays the soft copy output of text and graphics to the users.
• CRT Monitors: CRT monitors use a Cathode Ray Tube, including an electron beam and a phosphor coated screen for producing an image on the screen.
• LCD Monitors: LCT monitors use liquid crystal, which are activated by electric field to display the images of high resolution.
• Printers: printers are the output devices that are used to produce a hard copy output of the text or the documents stored in a computer.
• Impact printers: Impact printers are the printers in which a mechanical contact exists between print head and paper. The impression of characters is developed on the paper with the help of striking the ink ribbon by the print head.
• Non-impact Printers: Non-impact printers are the printers in which mechanical contact does not exist between print head and paper and ink is sprayed on the paper with the help of a nozzle to form an impression of the character.
• Plotters:  Plotters are the output devices attached with computer to plot high quality graphs or images.
• Drum plotters: Drum plotter is the plotter that consists of a paper mounted on a drum and pens to plot the graph. Both pens and papers on the drum are moved to produce images.
• Plat-bet Plotter: Flat-bed plotter consists of a plain surface known as bed on which the paper is fixed and only the pens are moved to produce an image or a graph.
• Speakers: Speakers are the output devices used to generate output in an audio format from the computer.
• Projectors: Projectors are the output devices that are used to project big picture of the data stored on some storage device such as CD and DVD on a white screen.
• Terminal: A terminal is a collection of an device and an output device that helps a computer in receiving as well as transmitting data.
• Intelligent Terminal: The terminal, which possesses all processing power, i.e. the logic required to perform operations such as calculations and formatting, is known as intelligent terminals.
• Smart Terminals: The terminal, which possesses small processing power, is known as smart terminal. It requires the help of a processor to perform certain operations.
• Dumb Terminals: The terminal, which possesses no processing power, is known as dumb terminal. It does not perform any operation.

Unit 7: Internet, Intranet and Extra net

Key terms to remember

• Internet: the internet is a large network of computers placed at different locations around the world that are connected to each other through telephone lines and satellites.
• WWW: The WWW is collection of interlinked hypertext documents stored on computers all around the world.
• Web Page: Web Page is a formatted document stored on a web server that can be accessed to gather information.
• Web Server: Web server is a computer that contains the web pages corresponding to the websites available on the internet.
• Web Browser: Web Browser is software, which is used to access the internet and the WWW.
• Search Engines: Search engines are websites, which provides the users the facilities of searching for information related to some topic.
• Email: Email is a service provided by the internet that allows two persons in remote places to communicate with each other.
• ISP: An ISP is an organization that provides the internet connections services to people who want to use internet.
• Gateway: Gateway is a computer, which contains all the software required for the transmission of data over different networks.
• Protocol: protocol is the set of rules and methods that are to be followed to transfer data from one computer to another on a network.
• IP (Internet Protocol): IP is a protocol that is responsible for the routing of data on the network.