Introduction to Computing

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Introduction to Computing

• Andrea Carlin
• Andrea_crln_at_yahoo.ie

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Definition of a Computer

• A Computer is an electronic device used to
  process data, converting the data into
  information that is useful to people.

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Computers consist of four parts

• Hardware
• Software
• Users
• Data

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Hardware

• Mechanical devices that make up the computer.
• Hardware is basically something that has size and
  shape and you see and touch it.
• Examples of hardware are
• System unit box
• Memory
• Storage devices.
• Input and output devices

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System Unit Box

• This is the single most important part of the
  whole system it is the computer. It is the box
  that is sometimes located underneath the monitor
  (known as pizza box) or it can be placed
  unterneath the desk upright (known as a tower).
  There is no differnce between the two types but
  the tower boxes have become much more common.

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The Central Processing Unit

• This refers to the computers Processor. It is
  where all calulations and manipulations of data
  are carried out.
• It is considered the BRAIN of the computer.
• This is commonly an Intel chip eg Pentium 1
  pentium 2, 3 or 4
• The speed of this chip is expressed in terms of
  hertz eh 800 megahertz.
• The higher the speed the faster the data can be
  processed.

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The Motherboard

• The motherboard's main job is to hold the
  computer's processor chip and let everything else
  connect to it. Everything that runs on the
  computer or enhances its performance is either
  part of the motherboard or plugs into it via a
  slot or port. A motherboard by itself is useless,
  but a computer has to have one to operate

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C.P.U.

• There are three main parts to the C.P.U
• Control Unit takes instructions in a given
  sequence and controls the movement of data in the
  computer.
• Arithmetic Logic Unit ALU Performs
  mathematical functions
• Main Storage also known as Memory that allows
  data to be stored for processing.

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Memory

• When you launch a program, it is loaded into and
  run from memory.
• There are two types of memory in a computer
• ROM Read-Only Memory
• RAM Random Access Memory

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ROM - Read Only Memory

• These chips store the basic instructions to bring
  the computer to life when you switch it on. The
  instructions contained there are generally
  programmed at factory assembly stage and cannot
  be changed.

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Ram Randon Access Memory

• These chips are used to store instructions and
  data while its on its way to or from the CPU.
  They provide a temporary storage area within the
  computer for such data.
• However, RAM chips cannot store information
  permanenty and lose it when the system unit is
  switched off. This is known as VOLITILE memory

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Ram Randon Access Memory Continued..

• Size of the RAM determines a computers Speed and
  Power. The bigger the size of RAM the faster the
  machine.
• Memory is measured in bytes but memory is so
  large that the term megabyte MB (millions of
  Bytes) is used.

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Memory Measurements

• Kilobyte (KB) 1,024 bytes
• Megabyte (MB) 1,000 Kilobytes
• Gigabyte (GB) 1,000 Megabytes
• Terabyte (TB) 1,000 Gigabytes

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Measurements continued

• Computer disk space is measured in bytes.
• There are eight bits in one byte, and One byte is
  equivalent to one character on the keyboard eg
  a,b,c,1,2,3.

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Storage Device - Hard Disk

• This is a device that stores data permanently
• It is a mechanical device that stores information
  megnetically on a metal disk. It differs from
  both ROM and RAM in that it does not lose its
  data when the system unit is switched off.
• It is known as NON-VOLITILE memory.
• Data stored there can be added to, updated or
  erased as required by the computer user
• The hard disk is referred to as the C drive

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Auxiliary storage devices

• The hard drive is not removable. Therefore if you
  should wish to transfer any data stored on one
  computer to another, the data must first be
  copied onto a removable disk.
• There are several types of removable storage
  media (also called auxiliary storage media)

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Storage Media

• Floppy Disk Drive (A Drive)
• CD ROM Drive (D Drive)
• CD-RW Drive
• DVD Drive
• USB Port

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Input and Output Devices

• Input devices accept data and instructions from
  the user.
• Output devices return data to the user.

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Most Common Input Devices

• The Keyboard.
• The Mouse.

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Most Common Output Devices

• The Monitor.
• The Printer.

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Software

• This is the general term used to describe the
  various programs used on a computer.
• Software is something that has no size and you
  cannot touch it, but a computer can do nothing
  without it.
• Software is continuously being developed and
  updated versions of software are released regulary

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Software can be divided into TWO categories

• Systems Software
• Application Software

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Systems Software

• Systems software are programs that are produced
  in order to manage and control the computers
  operation
• Systems software are normally referred to as the
  Operating System (OS)
• Examples of Sytems software are
• Windows 98, Windows 2000, WindowsXP

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Application Software

• Applicaion software refers to the various
  programs that are used to perform specific user
  tasks.
• The application program works in close
  association with the OP
• Examples of application software are
• Word, Excel, Access, Internet Explorer.