Topic 1.1-1.5

Topic 1.1-1.5

1. Peripheral devices

   • Monitor
   • Mouse
   • Speakers
   • Keyboard
   • Printer

2. Types of Software

   • System Software
     • Programs and files which make up the computer's operating systems
     • Eg. software to connect to printer, software that deletes files or folders
   • Applications Software
     • Also known as applications programs. Allow users to write letters, solve problems, or to play games
     • Eg. word processing, presentation software, desktop publishing, modelling software- spreadsheets

3. Main components of a computer system

   • CPU (Central Processing Unit) (Heart of the System
     • interprets and executes commands from the computer's hardware and software
     • Known as a microprocessor
     • Single integrated system found in many devices that involve control and moitoring EG. automatic stopping systems in trains
     • Microprocessors
       • Designed to carry out a specific task
     • Main Memory
       • Stores all of the data and instructions that enable the computer to function
       • Also known as internal memory, central memory, primary memory
       • Two types of main memory
         • RAM (Random Access Memory)
           • Internal memory chip where data is stored temporarily when applications are running.
           • Can be both read and written to
           • Volatile, contents are lost when power is turned off
         • ROM (Read Only Memory)
           • Stores data or instructions that need to be permenant.
           • Used to store the processes that the computer needs to go through when it is switched on
           • Retain its contents when the power is switched off
           • Non-volatile or permanent memory
           • Stores software known as BIOS (basic Input and Output System)- loads and runs the boot file ( the start-up instructions)
             • When the computer is switched on: BIOS checks that all the hardware devices are attached and are working properly, copies the operating system to the RAM, stores the date, time and system configuration on a battery-powered non-volatile chip known as a CMOS (a Complementary Metal Oxide Semiconductor)

4. Secondary or backing storage devices

   • Storage devices- store programs and data when the computer is switched off
     • Not the same as memory
       • Internal memory is inside the computer connected to the CPU. Backing storage is outside the computer
         • Portable hard discs, CD and DVD-ROMS, memory sticks and flash memory cards
   • Sometimes called backing/backup storage, secondary storage, external storage

5. Input devices

   • Used to put information into the computer

6. Output Devices

   • Take information from the computer for other uses

7. Operating Systems

   • Control input, output and backing storage devices
   • Load, run and storing applications programs
   • Handling errors that occur in application programs
   • Keeping a log of computer usage
   • Managing the user interface so that the user can communicate with the computer system
     • Command Line Interface
       • Specialist systems
         • Users type instructions
           • Users have to learn and remember commands and coding
       • Advantages: User communicates directly with the computer and can make decisions about exactly what they want to see happen
       • Disadvantages: Typing in commandscan be very slow and relies on the user remembering the way that commands have to be given to the computer. This can be difficult to edit or change
     • Graphical User Interface
       • Use pictures and symbols
         • Users just need to know what they represent
       • WIMP interface
         • Windows, Icons, Menus and Pointing Devices
       • Touchscreens
         • Post-WIMP interaction
         • Allows users to scroll, pinch and rotate images using fingers and thumbs
     • Difference between CLI and GUI
       • CLIs used by technicians and specialists
       • Users only need limited knowledge however with out a visible icon in GUI, users will not know how to access it

8. Using a computer System to communicate

   • Most common forms of communication