Ch 01-types-and-components-of-computers


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IGCSE ICT 0417 Chapter 1 - Types and Components of Computer System

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  • - BIOS (basic input/output system) stored in ROM and holds instructions used to "boot" (i.e., start) the computer up when first switched on. Other names for RAM & ROM Main memory / Primary Memory / Internal Memory / Immediate Access Store (ISA)
  • Ch 01-types-and-components-of-computers

    2. 2. Outline 2  Hardware Examples of hardware  Software Examples of software  Worksheet #1  The Main Components of a Computer System Input/output devices, CPU, RAM, ROM, storage devices  Worksheet #2  Operating Systems  Types of interfaces GUI, CLI  Different Types of Computer System Desktop, Laptop, Netbook, Mainframe, Palmtop/PDA  Worksheet #3  Recent Developments in ICT Cloud computing, e-books
    3. 3. Hardware 3 Definition: All the physical parts that make up the computer system. Examples of Hardware: Keyboard Mouse Monito r CD- ROM Motherboard Printer Digital Camera Scanne r
    4. 4. Software 4 Definition: The set of instructions that make the computer system do something.Types of Software:1- Application Software programs that allow the user to do specific tasks. 2- System Software programs that allow the hardware to run properly. Examples of Application Software: Word Processor Spreadsheet Database Presentation Web browser Tip: When asked to name types of software, do not use brand names. So, for example, you should use “word-processing” rather than Microsoft Word in an answer. Examples of System Software: Operating Systems Microsoft Win
    5. 5. Software (Continued) 5 Application software and its uses Word-processing applications Database Programs Spreadsheet applications. Presentation applications Desktop Publishing (DTP) applications Graphics Programs are used to produce letters, reports and memos. are used to store and retrieve information. are used for tasks that involve calculations or graphs and charts are used to create slide shows and presentation. are used to produce posters, letters and magazines. are use for artwork.
    6. 6. Worksheet #01 6 Hardware or Software Think about the differences between hardware and software and classify each of the following by putting a tick in the relevant box. Name of Item Hardware Software Keyboard Operating System Scanner Remote Control Word-Processor Web browser Spreadsheet Database Virus checker DVD-ROM Web design
    7. 7. Main Components of a General Purpose Computer System 7 Input Devices Processor and Internal Memory Output Devices Secondary Storage Devices Keyboard (Input Device) Printer (Output Device) Monitor (Output Device) Main Unit (CPU, RAM, an d Storage Devices) Mouse (input Device) Processor outputs information to output device. Input device sends data to Processor. Data going into the storage device.Data going out from the storage device.
    8. 8. Main Components of a General Purpose Computer System 8 Central processing unit (CPU) - Brain of the computer - Consists of millions of tiny circuits on a silicon chip - Does all the calculations and performs all the logical operations - Deals with the storage of data and programs in memoryRAM - Random Access Memory - Data is temporarily stored when running applications - This memory can be written to and read from - Contents are lost when power to the computer is turned off - It is often referred to as a ‘volatile’ or ‘temporary’ memory ROM - Read Only Memory - Holds instructions that need to be permanent such as BIOS - Data cannot be altered easily and can only be read from - Contents are not lost when the computer is turned off - It is often referred to as a ‘non-volatile’ memory
    9. 9. Worksheet #2 9 Tick one box next to each item to show which statements apply to ROM and which to RAM. 1- Contents are lost when the computer is turned off. 2- Contents are not lost when the computer is turned off. 3- Stores the programs needed to start up the computer (BIOS) 4- Stores application programs and data currently being used. RAM ROM Explain why it is important that a computer has a large amount of RAM.1- Applications run faster 2- more applications are able to run at the same time 3- users are able to move quickly between applications. Give one way a computer uses RAM and ROM RAM – used for temporary storage of programs and data while the computer is running. ROM – Used for storing the start-up instructions on the computer.
    10. 10. Operating Systems 10 Definition: Operating system is software that controls the hardware directly by giving the step-by-step instructions that tell the computer hardware what to do. Operating System tasks:1- Accepting inputs from mouse or keyboard 2- Sending outputs to the display monitor or printer 3- Recognises peripheral devices such as external hard disks, pen drive, web cam etc and makes sure that software needed for the hardware to run is installed. 4- Handles the storage of data – it keeps track of all the files and directories/folders on the disk. 5- Loads and runs software applications. 6- Manages the moving of data to and from a hard disk. 7- Handles system problems and alerts the user. 8- Manages system security. E.g allows passwords to be added /
    11. 11. Operating Systems (Continued) 11 An operating system needs a way of interacting with the user. The way the operating system communicates with a user is called the interface. Types of interfaces: 1- Command Line Interface (CLI) 2- Graphical user interface (GUI) ------------------------------------------------------------------------------------------------- Command Line Interface (CLI) Example of a Command Line Interface - Command Line Interface do not make use of images, Icons or graphics. - Users have to type in commands to carry out operation.( e.g copy, delete a file). Features:
    12. 12. Graphical User Interface (GUI) 12 Features of GUI Graphical user interface s are called WIMP Windows the screen is divided into areas called windows. Windows are useful if you need to work on several tasks. Icons these are small pictures used to represent commands, files or windows. Menus these allow a user to make selections from a list. Pointers this is the little arrow that appears when using Windows. It can be used to select and use icon and to select options found in menus.
    13. 13. (continued) 13 Post-WIMP Interface - Used in portable devices such as mobile phones, PDA's and tablets. - Icons and menus are used to input commands. - Uses more than one finger as the input device together with a touch screenFeatures Post-WIMP Interface Pinching – where you pinch your fingers together to zoom in or spread them further apart to zoom out. Rotating – where you use two fingers – one finger moves up and the other finger moves down to rotate the object such asan image. Swiping – where you swipe your finger over the touch screen to turn over a page of a document.
    14. 14. Comparing CLI and GUI Interfaces  Easy to use due to the visual nature of the interface.  The user has lots of visual clues as to what things do.  Less chance of user input errors.  Quicker to input commands.  To display all of the nice graphics required by a GUI takes a lot of computing power so quite a powerful computer is needed.  User restricted to pre- determined options. 14 Advantages of GUI Disadvantages of GUI Advantages of CLI Disadvantages of CLI  The User has direct communication with computer.  Has a wider range of commands to use.  User must remember complex commands.  Lots of typing needed for quite simple tasks.
    15. 15. Types of Computer  They usually have a better specification (e.g. faster processor, more RAM and ROM, a higher capacity hard disk drive).  Parts and connections tend to be standardised, which usually results in low costs.  The large casing allows good dissipation of any heat build- up.  Desktops are not particularly portable.  All the components need to be hooked up by wiring.  It is necessary to copy files, when you want to do some work elsewhere. 15 Advantages of Desktop Disadvantages of Desktop Personal Computers (PCs) or Desktop Computers - General purpose computer - Made up of separate monitor, keyboard, mouse and processor unit. 1
    16. 16. Types of Computer (continued)  Much smaller and lighter than desktop so easily transportable.  Since they are portable, they can link into any multimedia system (e.g. Projector).  Files do not need to be transferred between work and home which saves time.  They are Wi-Fi enabled which means they can access  networks including the Internet when a signal is available.  The keyboards and pointing devices can sometimes be difficult to use.  Heat dissipation is more difficult due to the structure of the laptop computers.  They have limited battery life so the user may need to carry a heavy adaptor.  Since they are portable, they are easy to steal! 16 Advantages of Laptop Disadvantages of Laptop Laptop Computers - Monitor, keyboard, pointing device and processor are all together in one single unit. - Laptops userechargeable batteries when used away from a power supply. 2
    17. 17. Types of Computer (continued)  Much lighter than laptops (smaller screen and no CD/DVDdrive reduces the weight).  Longer battery life (their low- power components require less energy).  Cheaper – because some of the more expensive components are left out.  Smaller keyboard can make them more difficult to use.  Smaller screen can make the text hard to read.  Smaller hard disk so less data can be stored.  Low performance when doing certain tasks. (e.g video editing)  Very small size makes them easy to get stolen. 17 Advantages of Laptop Disadvantages of Laptop Netbook computers- Netbooks are extremely small and light versions of laptops. - They have slightly reduced power and much smaller screens. 3
    18. 18. Types of Computer (continued)  Can be used to do very large jobs which require large memories and very fast processor time.  Capable of supporting hundreds, or even thousands, of users at the same time.  Can perform many jobs at the same time (parallel  They are very expensive to operate and maintain.  They need a high-level of training for people to be able to use them  They are very large and so are almost impossible to transport.  They generate a lot of heat and need to be in air- conditioned rooms. 18 Advantages of Laptop Disadvantages of Laptop Mainframe - Very powerful computers that are used in very large companies. - Used to control huge networks of computers often located globally (e.g Airlines) - Have parallel processors which means they can process many jobs at the same time. 4
    19. 19. Types of Computer (continued) 19 Palmtop5 Personal digital assistant (PDA)6 - A handheld computer, which is smaller than a laptop. - Does not not usually have a real keyboard. - Selections are made using a pen-like device called a stylus. There are a huge number of features of PDAs/palmtops and the distinction between them and mobile phones is almost non-existent. Features of a typical PDA Memory card for data storage Touch screen for entering data Phone calls Digital camera Virtual keyboard shown on a touch screen Internet access and web browser software Bluetooth or Wi-Fi for connectivity MP3 Player
    20. 20. Advantages & Disadvantages of PDA/Palmtops  PDAs are smaller/lighter and are more portable.  PDAs are easier to use whilst standing.  Many can be used as a mobile phone which means that two separate devices are not needed.  PDAs usually have smaller memory which limits the things they can do.  Have small keyboard which can be hard to use.  have a small screen which can make it difficult to read text.  PDAs are small and so are often lost. 20 Advantages of PDAs/Palmtops Disadvantages of PDAs/Palmtops
    21. 21. Worksheet #3 21 State one advantage and one disadvantage of using a laptop computer rather than a desktop computer. Advantage Laptop computer is smaller and lighter so it is more portable than desktop computer Disadvantage Laptops are compact and can get hotter than a desktop PC. Tick whether the following statements apply to a CLI (Command Line Interface) or a GUI (Graphical User Interface). Statement CLI GUI Instructions must be typed to get a computer to carry out an action. Icons represent programs. It is more important that users understand how a computer works. Menus are offered to help choose an action.
    22. 22. Recent developments in ICT  You have instant access to a huge amount of application software.  No need to install software on your computer.  You can access data from other devices.  You do not need to spend large amounts of money for software you only use  There is a danger of abuse by hackers and people who introduce viruses on the system.  Use of system could be expensive as resources are supplied after you pay for subscription. 22 Advantages of Cloud Computing Disadvantages of Cloud Computing Cloud Computing Cloud computing is internet based computing where programs and data are stored on the internet rather than on the user’s own computer. 1
    23. 23. Recent developments in ICT  Storage thousands of books on one device.  You have much more choice.  You can download books almost instantly.  Cheaper because there are no printing fees.  You can change the darkness of the lettering or the size of your font.  You must recharge an e- reader.  Some screens are not easily readable in sunlight.  They can cause eye-strain  Book piracy: easy to copy and distribute an e-book and the author receives no pay. 23 Advantages of E-books Disadvantages of E-books E-books and Newspapers E-books and e-newspapers can be read using a special reader, called an e-reader, or by a computer such as a netbook or tablet ( e.g i- Pad) 2 Advantages and disadvantages of e-books/e- newspapers compared to traditional books/newspapers.