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Computers (Chp 8)

Computers are everywhere. We tend to think of computers as our PC’s and laptops but nearly all our basicappliances etc. are controlled by computers.Computers have changed the way we live and have had a major effect on almost every part of our lives.

A computer cannot think for itself – it must be programmed by humans. – Humans give computers a set ofinstructions and this is a programme which the computer then stores and runs.

HardwareThe physical objects related to the computer.

Inputs & Outputs

Some devices are both inputs and outputs:• Touch screen monitors• Modems• Fax

Control (more on p.89-92)

Computers are used to control many things we take for granted.Examples:Robots – Car factories, factories, gamesRailway tracks – Switching systems etc.Sewing machines – Controls electric motor, speed, type of stitch etc.Dishwasher/washing machines – controls heat, time, type of wash etc.

These can all be pre-programmed which saves a lot of time, money and is a lot less likely to make mistakes.

Inputs

Devices that input information in tothe computer. (from user tocomputer)

Examples:• Keyboard• Mouse• Touchpad• Scanner• Bar code reader• Microphone• Webcam

Outputs

Information that comes from thecomputer, out to the user.

Examples:• Printer• Speakers• Monitor (screen)• Projector• CNC router

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Computer StorageInformation is stored on various devices and the computer then access this information.

Examples:

Hard disk – In the computer itself (usually 200GB upwards)

Floppy disks – No longer used (too big, easily breakable, don’t hold enough)

CD-ROM – (limited to 700 MB storage, too big, strong)

DVD – (417GB – holds a lot, takes a long time to burn information)

USB Flash drive & flash memory (Quick & getting quicker, doesn’t rely on moving parts, small, can have very

big memory capacity, portable)

Portable Hard drive (very big storage capacity)

Cloud – Online storage – stored on a hard drive in data centres (instant access, can’t lose it etc.)

Computer memoryROM – Read-only memory (like computers long term memory – used to hold information on basic computer

operations and cannot be modified)

RAM – Random access memory (used to run programmes – usually 2GB, 4GB or 8GB)

SoftwareSoftware is all the programmes that direct the computer about what to do and how to work

Operating system – The main programme that then runs everything else.

E.g. Windows XP, Windows 7 and Mac OSX. (also iOS and Android on smart phones)

Word Processor – to write letters/reports etc.

E.g. Microsoft Word

Spreadsheet – For putting information in table format and ding calculations

E.g. Microsoft Excel

Presentation – For presenting ideas/information to people

E.g. Microsoft Powerpoint, Prezi

Publishing – For designing leaflets, information letters, posters etc.

E.g. Microsoft Publisher

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Database – A computers filing system. Used to store information for businesses/companies. Makes key

information easy to access

E.g. ePortal in school

CAD – Computer Aided Design – Assists in design for engineering, architecture etc. Saves having to drawing

things out by hand on paper.

Advantages:

• More accurate

• Neater drawings

• Easier to fix mistakes

• Easier to share with others (email etc.)

• Easier to reuse all/some of drawing

E.g. Solidworks, AutoCAD, PowerCADD

CAM – Computer Aided Manufacture – Computers are used to run machines/manufacturing in factories/

labs etc. Similar advantages as CAD as well as being much safer and quicker

Graphics software – Used for visual and artistic design. Logos, packaging, photography etc.

E.g. Paint, Photoshop, Gimp, etc.

Other Computer termsInternet / World Wide Web (www)

Websites - Electronic pages kept online

Email – Most have online email accounts now using cloud storage

File – collection of information that a computer uses – e.g. Microsoft word file for your project folio

Bits & Bytes -

Smallest piece of computer data is stored in memory called a bit. It has two values – on (1) or off (0)

Bits are stored in groups of 8 called bytes

• Kilobyte (KB): 1000 bytes

• Megabytes (MB): 1,000,000 bytes Example: Smart phones come in 4GB, 8GB 16GB memory

• Gigabytes (GB): 1,000 megabytes

• Terabytes (TB): 1,000 Gigabytes

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Pixels – Letters and pictures appear in pixels – little squares of colour (the more pixels the better quality)

E.g. iPhone has 8MP camera (8,000,000 pixels)

Other key terms:

GPS – Global Positioning System (used in sat navs)

MP3 – MPEG Audio layer 3 (compressed digital files)

MP4 – MPEG 4 – (Compressed video files)

*Key things to know• How have computers affected our lives?

• How have computers affected the world around us? – workplace, factories, environment etc.

• ***What impact has the internet had on society?

• How has social networking affected the way young people live?

• What are some disadvantages of social networking sites?

• What are the advantages of CAD and CAM?

• What are the advantages of computer controlled machines in factories?