Slide 1 August 2004 Standard Grade Computing Hardware.

August 2004

Standard Grade ComputingSlide 1

Hardware

August 2004


HardwareHardware

All the physical parts of a computer like a mouse, printer, keyboard and monitor are called hardware. A single item of hardware is called a device.

Input Devices

Backing StorageDevices

Processor Main Memory

Output Devices

Eg. Keyboard, mouse

Eg. Monitor, Printer

Eg. Hard Disk, Floppy Disk

August 2004


Types of ComputersTypes of Computers

Mainframe - The biggest type of computer. Fills a whole room, costs hundreds of thousands of pounds and is used by banks, large universities and large businesses.

Desktop - A ‘normal’ computer system that fits on or under a desk.

August 2004


Types of computers Types of computers (continued)(continued)

Laptop/Notebook - A portable computer designed to be moved about easily. It is lightweight, powered by batteries, uses a flat screen, has a standard keyboard with a touch pad and may have wireless networking built in.

Palmtop - A portable computer designed to fit in the palm of your hand. Has a handwriting input system and on-screen keyboard. Used as a diary, organiser, word processor, calculator and for communications.

August 2004


A Computer SystemA Computer System

A typical Computer System will have all of the following devices:

•Keyboard

•Mouse

•Monitor

•Base Unit (Including CPU & RAM)

•Printer

Extras will be:

•CD-ROM (or DVD) Drive

•Speakers (with sound card)

•Scanner

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The Base UnitThe Base Unit

Can be a Desktop Unit, or a Tower Unit and will contain the following devices:

Central Processing Unit (CPU)

Main Memory Network Card

Floppy Disk Drive

Hard Disk Drive

Graphics Card Sound Card

August 2004


The Central Processing UnitThe Central Processing Unit

A Central Processing Unit (CPU) is contained on a single chip. The CPU carries out: sorting, searching, calculating and decision making. Examples are Intel Pentium and AMD Athlon. The CPU is a microprocessor.

To find out more about microprocessors, take a look at:

http://computer.howstuffworks.com/microprocessor.htm

August 2004


MAIN MEMORYMAIN MEMORY

Main memory refers to a group of chips inside the computer. When you run any program, such as a word processor or a game, the program is loaded into main memory from the hard disk or CD ROM.

Memory is organised into small ‘compartments’ called storage locations. Each storage location can hold a small amount of information and is identified by a unique address.

August 2004


Main memory is made up of two types of memory chips:

1. RAM (Random Access Memory)• Contents are lost when the computer is

switched off. (Volatile)• Can be changed – The CPU can write to

memory. • Used to store programs and data temporarily.

2. ROM (Read Only Memory)• Contents not lost when the computer is

switched off. (Non-Volatile)• Can not be changed – The CPU can only read

from memory. • Used to store the Operating System on

palmtop computers.

August 2004


Credit

Effects Of Changes In TechnologyEffects Of Changes In Technology

Changes in technology have led to computers which are faster, cheaper, smaller and more reliable. This is because:

1. Price of memory chips has decreased.2. Size and speed of memory (RAM & ROM) has increased.3. CPUs work faster and can handle more data

in a single operation. 4. Powerful computers can now be made very

small.

August 2004


Quick Questions1. The microprocessor which controls all the computer’s

activities is part of the CPU. What do the letters CPU stand for?

2. Describe one task done by the CPU.

3. A Computer’s main memory is made up of both ROM and RAM. What do the letters ROM and RAM stand for?

4. In a computer, the CPU is often a microprocessor chip. What is a chip?

5. Clark is a news reporter working for the Daily Globe. He has a palmtop computer to help him take notes. Why might Clark find this type of computer particularly useful?

August 2004


Backing StorageBacking Storage

Backing storage is where you store and save programs and data.

Backing Storage

Media

Backing Storage

DevicesUsed For Capacity

Hard disk Hard disk drive Storing main programs 20-200Gb

Floppy disk Floppy disk drive Saving data files 1.44Mb

Magnetic tape Tape drive Taking backups 4-200Gb

CD ROM CD ROM drive Games & Music 800Mb

DVD DVD drive Movies/Music 4.7 - 17Gb

August 2004


Backing StorageBacking Storage MediaMedia

1. Hard diskA circular metal disk coated with magnetic material.

Advantages: Fast access to dataStores a lot of data (High Capacity).

Disadvantages: Can be corrupted (although normally reliable).

Type of Access: Random.

August 2004


2. Floppy disksA thin plastic disk coated with magnetic

material and enclosed in a hard plastic cover.Before you can use a floppy disk it must be

formatted. Formatting produces invisible circles (tracks) and lines (sectors) of magnetism on the surface of the disk.

Unformatted Formatted

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2. Floppy disks (Continued)

Advantages: CheapFast access to data (slower than

hard disc or CD).

Disadvantages: Can be corrupted easilyDoesn’t store much data (Low

Capacity).


August 2004


3. Magnetic tape

Similar to cassette tape.

Advantages: Can store lots of data (High Capacity).

Disadvantages: Slow to access.

Type of Access: Sequential (Serial).

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4. CD ROM - Compact Disk Read Only Memory. This looks just like a music CD.

Advantages: Can store huge amounts of information compared to a floppy disk (but not as much as a hard disk). Fast access to data.

Disadvantages: Data cannot be changed.

Examples: Encyclopaedias, databases, historical material.


August 2004


5. DVD ROM – Digital Versatile Disc Read Only Memory.

Similar to Compact Disc (CD), a DVD holds a minimum of 4.7Gb of data, enough for a full-length movie. New technology allows up to 17Gb of data to be store on one DVD disc.

Advantages: Can store more than CD.

Disadvantages: Data cannot be changed.

Examples: Film rental.


August 2004


6. Recordable Media

• CD-R are blank CDs which can be recorded on once only, then the data is stored permanently.

• CD-RW are blank CDs which can be written and erased as many times as you like.

• DVD-R are blank DVD which can be written once.

• DVD-RW are blank DVDs which can be erased and recorded over many times.

August 2004


7. USB Flash Drives

These are small, portable devices which plug into a computer’s USB port and work like a portable disc drive with up to 2GB of storage capacity. USB flash drives have less storage capacity than a hard drive, but they are smaller, portable and more durable because they do not contain any internal moving parts. They store much more than a floppy disc and do not corrupt as easily.

August 2004


Summary of Backing Storage Devices

Backing Storage Speed Cost Capacity

Hard disk Very Fast £50 - £200 20-200Gb

Floppy disk Slow 20p 1.44Mb

Magnetic tape Slowest £5 - £50 4-200Gb

CD ROM Fast 30p 800Mb

DVD Fast 50p 4.7 - 17Gb

USB Drive Very Fast £20-£150 128Mb – 2Gb

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Sequential Access (Serial Access)Accessing data in the same sequence as it was originally stored. This type of access is very slow.Example: Tape.

Random Access (Direct Access)You can access any data from a disk directly because the read/write head on the disk drive can jump straight to the track where the data is stored, without having to read all the data in between. This type of access is very fast.Examples: Floppy Disk, Hard Disk, CD, DVD.

August 2004


MultimediaMultimedia

This is the use of sound, animated images, video and graphics. Used in interactive learning systems and games.

Multimedia systems requires the following1.Sound input: using a sound card, from a

microphone, or CD player.2.Graphical input: using a graphics card, from a

video or still digital camera.3.A range of high quality output devices: high

resolution monitor, stereo speakers.4.Large amount of RAM.5.High speed and high capacity backing storage.6. A fast processor.

August 2004


Homework Questions

1. What is multimedia?

2. Why is sequential access slower than direct access?

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Input DevicesInput Devices

1. Mouse

2. KeyboardThe input device used most often with a computer system

3. Track ballAn upside down mouse. Used in portable computers. Why?

Not This kind!

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4. JoystickUsed for game play.

5. Graphics tabletA flat pressure-sensitive board with a pen or pointer connected to it. Used in Computer Aided Design.

August 2004


6. Touch-sensitive screen

Uses include information guides, tourism and museums.

7. Scanner

A scanner allows you to input drawings, photographs,

bar codes or text directly into a computer.

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8. TrackpadAlso known as a Touchpad, a trackpad is used with a laptop computer in place of a mouse to move the cursor around the screen.

9. Web CamUsed to view people or places

on the internet.

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10. Digital Still CameraA camera without film. Images are recorded on sensors and stored in memory. Images can then be transferred to a computer for viewing or printed out on a high quality colour printer, or uploaded to a web site.

11. Digital Video CameraVideo is stored digitally on tape. It can be transferred to a computer for editing with software such as iMovie or Windows Movie Maker. The finished movie can be transferred back to the tape for viewing or saved as a computer file.

August 2004


12. Voice Recognition

You can to give instructions to the computer by simply speaking to it. You will need a computer fitted with a microphone and voice recognition software. The microphone must be connected through a sound card.

13. Hand Writing RecognitionUsed in palmtop computers for input. User ‘writes’ on the screen, often in a special script, and the computer turns it into text. (The computer often makes mistakes, but technology is improving)

August 2004


Homework Questions

1. Disks must be formatted before they can be used to save data.. Draw a diagram to show what a floppy disk looks like before and after it has been formatted.

2. Which of these input devices (TRACKBALLMOUSE JOYSTICK)would be used with:a: A computer aided design (CAD)packageb: A computer gamec: A wimp system

August 2004


Output DevicesOutput Devices

1. Monitor / Visual Display Unit (VDU)The main output device of a computer,used to display text & images. Monitorsare measured in inches with 15”, 17” and 19” being

common.

2. LCD - Liquid Crystal Display ScreensFlat screens used in portable computers

3. TFT – Thin Film Transistor Screens. Flat screens which are higher resolutionthan LCD but are more expensive.

Both LCD and TFT are used in laptop and palm top computers, but are also now common on desktop computers.

August 2004


4. Printers

Laser – A laser beam is used to make an image of the page on a photosensitive drum. Toner sticks to the image and is transferred onto paper. Hot rollers fuse the toner onto the paper to make the image permanent. Can be black & white (mono) or colour.

Inkjet – Coloured ink is squirted out of tiny nozzles onto paper to form an image. Inkjets can produce very high resolution images.

August 2004


Summary of PrintersSummary of Printers

Name Speed Resolution Capital Costs Running Costs

Laser 10-20ppm 1200 x 1200 dpi Expensive £200-£2000

Low

Inkjet 1-8ppm 4800 x 1200 dpi Cheap £50 - £200

Very High

Colour Laser

4-20ppm 1200 x 1200 dpi Expensive £500-£4000

High

August 2004


5. Plotters

A plotter uses a pen to draw the computer output onto paper. There are 2 types:

(i) Flat bed plotter - the paper is fixed and the pen moves in two dimensions.

(ii) Drum plotter - the pen moves in one direction and the paper is moved in the other direction by rotation of the drum.

Uses: Computer Aided Design (CAD)

August 2004


6. Voice output

A computer can synthesise (make) speech if it has the necessary software and loudspeakers.

Uses: visually impaired & disabled.

EclipseThe Eclipse system based on picture/symbol overlays for input with digitised speech for output.

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Virtual RealityVirtual Reality

The system creates the illusion that the user is part of the computer’s world and can move about and manipulate that world.

Input devices- Gloves fitted with sensors allows wearer to

manipulate objects.- Suits allow people to walk through the virtual

world.- Headset allows the wearer to look around the

virtual world.

Output devices- Headset allows a visual output to a pair of small

screens and sound to a pair of speakers.

August 2004


Homework Questions

1. Name one specialist input device and suggest who might use it.

2. Name one specialist output device.

3. a) Make a list of those input and output devices mentioned which you have seen. b) Note beside each where you saw it.c) How many of them do you think are available in school?

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Slide 1 August 2004 Standard Grade Computing Hardware.

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