OCR AS ICT Unit 1 Chapter 2

Hardware: The physical components that make up a computer. (e.g. mouse)

Software: The programming code that makes the computer work. (e.g. applications)

• System software: Control the working of the computer. (e.g. OS)
• Application software: Help complete a certain task. (e.g. word processor)

Standardisation: The imposition, by a third party, of a set of standards on manufacturers.

Advantages of standardisation:

• Allows hardware from one manufacturer to work with that from another. (e.g. USB)

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A lack of standardisation is when hardware/software made from one company isn't compatible with others made from another company.

Disadvantages of a lack of standardisation:

• No communication between systems.
• Purchasing a computer that isn't part of a global standard > all upgrades and parts have to come from specific sources > very expensive.
• New equipment is needed to bridge gap > very expensive.
• Limited technical support on the systems > very expensive.

Input Device: Device that gets external information into a system.

• Keyboard - QWERTY, alphabetical, dvorak, concept.
• Mouse - joystick, tracker ball, touch pad.
• Scanner:
  • Barcode - tills - convert barcode to numbers
  • Optical Mark Reader - lottery - checks for present marks
  • Magnetic ***** Reader - credit cards - reads data on magnetic *****
  • Flatbed Scanner - takes image and converts to digial information.
• Graphics Tablet - flat working areas that has a stylus that can write on it.
• Digitiser - an item that converts analogue into digital.
• Microphone

Output Device: A device that displays the result of processing to the user.

• Monitor - Displays signals from a computer from a computer.
• Printer - Print hard copies of information from a computer.
  • Laser Printer - High resolution non-impact, colour and black & white, high costs.
  • Inkjet Printer - Spray ink on paper, quiet, colour and black & white, low costs.
  • Dot Matrix Printer - Impact printer, noisy, colour and black & white.
• Speakers
• LED

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Storage Device: A device that stores data.

• Hard Disk Drive
• CD-ROM   = Portable (stores 700mb)
• DVD   = Portable (stores > 4.7GB)
• USB Memory Sticks   = Portable (large storage capacity)
• External Hard Drives = Portable

Visually Impaired: People who have a loss of vision - it may be total loss of vision in one or both eyes or partial loss.

• Braille Keyboard - a keyboard with Braille dots on the keys
• Microphone - an input device for voice recognition.
• Loudspeaker - an output device for hearing signals and text read out.
• Screen magnifier - a magnifying glass that fits on top of the screen and enlarges parts of it.
• Braille printer - an impact printer that can create Braille on a page.

Motor Impaired: People who have a loss or limitation of function in muscle control or movement.

• Mouth stick - a stick for controlling input with the mouth.
• Puff-**** switch - a tube placed in the mouth and blown/sucked through.
• Eye typer - a device that fits onto the muscles around the eye and when the eye is moved a pointer on the screen moves.
• Foot mouse - a mouse that is controlled by the foot.

Specialist software for the physically impaired:

• Text-to-speech system - Takes written text and outputs it using a speech synthesiser.
• Speech-to-text system - Takes spoken words and inputs them into a computer.
• Screen Magnifier - Zooms in on areas of the screen.
• Predictive Text - Suggests the required word as the letters are typed.
• Sticky Keys - Allows keys to be pressed once and the system acts as if been held down.

4 Main Types of Software:

• Operating Systems:
  • Controls the allocation and use of hardware resources (e.g. memory, CPU time and hard disk space)
  • Performs basic data management tasks (e.g. recognising input from the keyboard).

• User Interfaces:
  • The means by which the user interacts with an application or operating system.

Styles of User Interfaces:

• Command Line - User types instructions with a command prompt to control what the computer does.
  • Many commands have switches > Adds functionality.
  • Useful for running commands which can't be accessed from a menu or form.
  • Good for experienced users.
  • Low memory overheads than a GUI > Run commands faster.
  • Need to know the commands.
  • Lots of typing so errors are common.

• Forms - Provides prompts to fill in information.
  • Guide inexperience users by entering the relevant information in a structured manner.
  • Data entry boxes can be validated.
  • Limited options are presented > not flexible.

• Menus - A series of related items that can be selected. (either pop-up or drop-down)
  • Can be cascaded (one menu leads to another)
  • Experienced users can't jump through screens.

• Natural Language - Allows the users to use their own language to communicate with the computer.
  • Two Types of Natural Language:
    • Spoken - Typified by voice recognition software in word processors.
    • Written - Questions are types in natural language.

• WIMP - Windows, Icons, Menus and Pointer. (A type of GUI)
  • Easy to use for beginners.

• Utilities:
  • Programs that assist in the monitoring and maintaining of the computer system. (e.g. Virus checkers, file compression software and printer monitorying software).

• Applications Software:
  • Allows the computer to be used to solve problems and perform tasks for the user (e.g. word processors, databases and spreadsheets)