ITGS - Ch 2
Source: Information Technology in a Global Society by Stuart Gray

The tangible, physical parts of the computer which work together to input, process, store and output data.

  • Supercomputers -*High processing speeds through Multiprocessing
  • Supercomputing Super Powers (BBC) provides a graphical breakdown of the fastest supercomputers by speed, country, and operating system. Click the image below to explore these Supercomputers.
  • Mainframes
  • Desktop computers - *Home theatre PCs
  • Laptop computers
  • Notebooks
  • Personal Digital Assistants (PDA) - Check out Pocket marvels: 40 years of hand held computers. Compiled by Computer World
  • Smart Phones
  • Embedded systems

Staying in Sync

•All portable computers come with software to allow data synchronization with a ‘main’ desktop or computer •Connections can take place using USB cable, infra-red or Bluetooth

Input Devices

•Keyboards/concept keyboards/soft keyboards



•Game controllers

•Barcode scanners

•Magnetic stripe readers

•Smart cards

•Optical Mark recognition

•Magnetic ink character recognition


•Sensors and probes

•Digital cameras

•Web cams

•Radio tags

•Radio frequency identification (RFID)

Concerns about RFID

Input Devices of the Future?

Output Devices

  • Screens
  • Speakers
  • Printers

Computer Access for the Disabled

Processor Technology


Clock Speed


Multicore processors


Storage Devices

•Primary storage-High speed, electronic memory.

         -Random access memory - Temporary (volatile) storage for programs and data                   being used in the moment.

        –Read only memory - Storage that cannot be changed. Contains the computer's                 BIOS which tells the computer how to boot up.

•Secondary storage - Stores data and programs installed on a computer system.

         –Magnetic tapes -Often used for back up but show to access because the data is                sequential.

         –Magnetic disks -Your hard drive.  High capacity, high speed

–Optical storage

–Flash memory - * See "Common Mistake" note on page 34

Hard Disk Security & Privacy

What happens to data stored on computers that are lost, stolen, thrown away or recycled? How can you ensure your data is safe or properly erased? (See page 35)

Watch Ghana: Digital Dumping Ground shows what can be found on the hard drives of recycled computers.

Storing Data: Bits and Bytes

All data on your computer is stored as zeros and ones or bits. Those bits are then grouped together into more meaningful units called bytes.

ASCII - American Standard Code for Information Interchange. A standard coding scheme for representing the English alphabet.

Unicode - Modern coding scheme which uses up to 4 bytes to represent each character, allowing many thousands of characters. Used to include non-English alphabets.

Plane Text - Specifies the characters that make up a text but do not include ways to specify other formatting attributes such as the font type, size, bold, underline, and color. ASCII and Unicode are examples of plain text.

Graphics Standards - Computer graphics are represented as bit and bytes like other computer data. Typically each pixel in an image uses three bytes of store space - one byte for red, one for green and one for blue.

Failover Systems

Ports & Connectors

Designed to keep a system running if the primary system fails  due to hardware or power failure.

RAID - Redundant Array of Independent Disks. Uses multiple hard disks, connected together to create a fault tolerant system.

UPS - Uninterruptible Power Supply. Provides power in case of an electricity failure.