Chapter 2

Chapter 2

1. Standardisation - The imposition of a set of standards on manufacturing

   • Upheld by 3rd parties and trading standards association
   • Ideally everything within an industry would be standardised
   • Problems
     • Cost - Unstandardised hardware may require specific peripherals and devices
     • Availability - Unstandardised hardware may lead to low supplies in compatible devices
     • Tech support - Little tech support for unstandardised prodcuts
   • Examples: USB 2.0 Standard port, windows as a standard OS

2. Input Devices

   • Graphics tablet
     • Stylus input
     • Custom interface
     • Used by designers and architechts
     • Flat working area
   • Digitiser
     • Any device which turns analogue to digital
     • E.g. graphics tablet, scanner, camera
     • generic description
   • Keyboard
     • Good for small amounts of input
     • Custom keyboards for specific tasks
     • Different layouts e.g. QWERTY and DVORAK
     • Often combined with a mouse
   • Scanner
     • OMR optical mark reader
     • MICR for bank cheques
     • Magnetic card reader
     • Barcode translated to product ID
   • Mouse
     • Combined with WIMP interface
     • Variations: rollerball trackerball joystick touchpad
     • Needs space to operate
     • Ergonomic design

3. Output devices

   • Plotter
     • Page size variety A3 A2 A1 etc.
     • Uses mathematical co-ordinates
     • Very accurate
     • Architectural designs
   • Monitor
     • Variety of sizes
     • Signals from computer displayed on screen
     • Resolution W*H e.g. 1920*1080
   • Printer
     • Ink Jet
       • b/w and colour
       • Replaceable cartridges
       • Spray ink onto paper
       • Cheap to buy
     • Dot Matrix
       • Cheap easy to maintain
       • Uncommon
       • Impact piercing
       • carbon forms
       • old
     • Laser Jet
       • High quality
       • rotating mirror reflects laser onto photosensitive drum
       • Reliable
       • Toner is attracted to negative charge

4. Storage devices

   • HDD
     • 1-3TB
     • Internal component (usually)
     • Portable
   • CD/DVD
     • 0.5-5GB
     • Optical storage device
     • Easily scratched/damaged
   • Magnetic tape
     • Huge capacity
     • Backup networks
     • Very cheap
   • Flash Drive
     • 0.5-16GB
     • Portable
     • Personal use

5. Specialist software

   • Text to speech
     • Analyses text and converts it to audio speech
   • Speech to text
     • Converts analogue (audio) words into digital text
   • Auditory feedback
     • Plays sounds (alerts) in response to user input
   • Screen magnifier
     • Can zoom in portions of a monitor for visually impaired users
   • Sticky keys
     • Allows the system to think keys are being held down after one push
   • Predictive text
     • Suggests words related to keys pressed

6. Specialist Hardware

   • Speakers
     • feedback
     • Output visually impaired
   • Braille printer
     • outputs docs for visually impaired
   • Microphone
     • Speech to text
     • Quick easy input
   • Braille keyboard
     • used by visually impaired
   • Eye typer
     • camera focuses on eyes
     • different motions control cursor
   • Tongue Joystick
     • manipulates cursor
     • connected to head
     • pushed with tongue
   • Foot mouse
     • 2 pedals L/R click
     • mouse maneuvered with feet
   • Puff/Suck
     • manipulate the cursor with air flow
     • specialist software has additional controls

7. Types of Software

   • Operating System
     • Controls allocation of hardware resources
     • Controls basic input and output
     • E.g. Windows, Linux, OSX
   • User interface (UI)
     • Method of interacting with an application or operating system
     • E.g. menu command line natural language
   • Command Line
     • Requires codes
     • Need knowledge
     • can cause damage
   • Graphical User Interface (GUI)
     • WIMP
       • Windows
       • Icons
       • Menus
       • Pointer
     • Based on graphics rather than text
   • Natural Language
     • speak real english
     • Converted to digital
   • Utility
     • Small program performing monitoring and maintenance tasks
     • E.g. Anti-virus disk manager defrag
   • Application
     • Solves particular tasks or problems
     • E.g. Word processor Spreadsheet Databases
     • Creates documents and files