Unit 4 Hardware and Networks

Unit 4 Hardware and Networks

Information System Design &

Development

National 5

Hardware and Networks

Hardware

An essential part of designing an information system is the selection of suitable hardware.

Memory: RAM & ROM

The main memory of a computer comprises RAM and ROM. Random access memory (RAM) is the largest part of the main memory, storing the operating system, programs and data while the computer is switched on.

The main differences between RAM and ROM are that ROM is small permanent memory that does not get written to by the user during normal operations whereas RAM is larger, temporary storage which loses its contents when the computer is switched off.

People often get confused between main memory and backing storage, they are not the same.

Main memory is located inside the computer system. It can either be RAM or ROM.

Backing storage is outside the main processor, e.g. Hard Drives,

CD/DVD drives, USB Flash Memory (Pen Drives).

Main memory in today’s computers is on average around 4-6 Gb of RAM.

Backing Storage is much bigger with average computers having around 1 Tb or more.

ROM (Read Only Memory)

ROM is used to store a small part of the operating system called the bootstrap loader.

• Data is stored permanently in ROM, it is not lost when the power

goes off

• Data in ROM cannot be changed

• ROM holds vital systems data programs.

2

RAM (Random Access Memory)

• The processor can write to and read from RAM at high speed

• Data held in RAM can be changed

All data in RAM is lost when the power is switched

off

• RAM is the working space of the computer. It holds all of the programs and data files currently in use.

Measuring the size of memory

We use these terms when measuring computer memory.

Bit Binary digit : a single 1 or 0

Byte

Kilobyte

Megabyte

8 Bits, for example 11001110

1024 bytes

1024 Kilobytes

Gigabyte

Terabyte

1024 Megabytes

1024 Gigabytes

Watch the video – “RAM and ROM”

The Central Processing Unit - CPU

The CPU or processor is the brain of the computer, controlling everything that takes place on the computer, e.g. movement of data and any calculations to be carried out.

Most computers today have more than one processor working together to improve system performance. The processors on mobile phones and tablets will be different to the ones on a normal desktop. These mobile processors might not be as powerful as the desktop equivalent but will be designed to use less power so that the battery on the phone or tablet lasts longer. In addition to this, different companies compete with one another in the processor market and different computer manufacturers can use differing processor types, which can make comparing computers difficult.

A processor is made of silicon crystal wavers, which hold millions of tiny electronic components.

3

Processor Types

Multiple core processors

These have two or more processors working together to make the system work better. For example there are duo-processors, with two or more processors working together, quad processors, with four processors working together and even hex-core processors with six processors.

Low Power Processors

These have lower clock speeds and use less electricity. They are used in laptops, net books, mobile phones, MP£ players, tablet computers and games consoles.

Watch the video – “Computer Hardware _What is a

Processor”

Clock Speed

Clock speeds are a measure of how powerful a processor is, for example

3GHz. Clock speeds are measure in Megahertz (MHz) or Gigahertz (GHz). 1

MHZ = 1 million pulses per second; 1GHz = 1000 million pulses her second.

The clock pulses measured in GHz, regulate and coordinate the activities in the processor.

1000 million pulses per second - this measures how many times per second the system clock pulses. If the computer carries out an instruction or calculation with every pulse of the system clock then the faster the system clock ticks or pulses, the more operations will be carried out per second.

Unfortunately it isn’t as simple as just comparing clock speeds of computers because as there are a wide number of processor types and manufacturers on the marketplace and they perform differently so other measures need to be taken into account as well, such as the amount of memory a computer has installed.

4

Below is an example of a typical processor type and speed.

Apple iMac Processor

2.9GHz quad-core Intel Core i5 processor

(Turbo Boost up to 3.6GHz) with 6MB L3 cache

Exercise

Watch the video – “Clockspeed”

6.

7.

1.

2.

Which part of the computer controls everything that happens within it?

What is the name of the basic measure of a computer processor’s performance?

3.

5.

What is the unit of measurement for the measure mentioned in question

2?

4.

Research and list three different companies that manufacture computer processors.

Which one of these statements about RAM and ROM is true?

A Neither ROM nor RAM holds data when the power is switched off.

B RAM holds data when the power is switched off and ROM doesn't.

C The user can write data to RAM but not to ROM.

D The user can write data to ROM but not to RAM.

Which generally holds more data, RAM or ROM?

When a computer is first switched on, which type of memory is read from first and why?

5

Backing Storage

When we talk about ‘storing’ data, we mean putting the data in a known place.

We can later come back to that place and get our data back again.

‘Writing’ data or ‘saving’ data are other ways of saying ‘storing’ data.

Reading’ data, ‘retrieving’ data or ‘opening’ a file are ways of saying that we are getting our data back from its storage location.

Backing storage devices are used to store the programs and data that the computer can access. The contents of backing storage are not lost when the power to the computer system is turned off.

There are two ways to access data on a backing storage device: randomly or sequentially. Random access means that particular files can be jumped to without having to read through all of the data, in the same way a user might select a track from a CD or a scene from a DVD. With sequential access, the user has to run through all of the data to find a file (similar to fast forwarding on an old video tape).

Type of access Backing storage device

Random/direct Hard disk drive, memory cards, flash drive, CD,

DVD and blu-ray drives

Sequential/serial Magnetic tape drive

6

Magnetic

Magnetic

Hard Drives

Magnetic Tapes

Floppy Disk

Zip Drive

Hard Disk

Capacity

500Gb – 1Tb

1.44Mb

750Mb

The hard drive is the main storage device for programs and files on personal computers. They have a very large storage space, usually measured in gigabytes (but some are now into terabytes).

This is a metal disk with magnetised surfaces on which data is stored as patterns of magnetic spots. The disks are in sealed units to stop dust and dirt corrupting data. They are usually fixed in the computer but you can get portable external drives.

Advantages

Fast access times, direct access

Fast data transfer rates

Cheap per megabyte.

Watch the video – “Hard Drives”

Magnetic Tape

These small cassettes (similar to old 8mm video camera or audio cassettes) are mainly used as backup systems for large networks. The tapes can store a lot of data but retrieving data can be slow as the user has to fast forward and rewind through the tapes to get to the data.

7

Optical Storage

Optical Capacity

CD-ROM

CD-R

CD-RW

DVD-ROM

DVD-R

DVD-RW

Blu-Ray

700Mb

700Mb

700Mb

4.7 - 17Gb

4.7 - 17Gb

4.7 - 17Gb

25Gb

These disks use lasers to read data ‘burnt’ onto the disk surface.

Read-Only storage devices such as CD-ROM, DVD-ROM and Blu-Ray have data written onto them when they are manufactured. This data cannot be changed.

CD-ROM

CD-ROM stands for Compact Disk – Read Only memory. It is fast and can store up to 700 Mb of data.

It cannot be written to – the data is fixed at the time of manufacture. The data is read by a sensor that detects laser light reflected from the surface of the disk. The speed of a CD drive is given as a number, for example

52X (52 X 150 Kilobits per second).

Used to distribute all sorts of data: software (e.g. office applications or games), music, electronic books, (e.g. an encyclopaedia with sound and video.)

CD-R

This is CD-recordable – it allows you to record data once. One data is recorded on it, it works just like a CD-ROM. It is read only. It can hold 700

Mb of data. The speed of a CD-R drive is given as two numbers, the read speed and the write speed.

CD-RW

This is rewriteable so you can record data over and over again, just like hard disks. You can use them to make backups of large files, for example groups of photos, and you can change the data stored on the disk as often as you want.

8

DVD-ROM

A DVD-ROM uses optical technology to read data. Like a

CD-ROM it is read only.

A DVD-ROM has much larger data capacity than a CD-

ROM. Single-sided single layered DVDs have a capacity of 4.7 GB. Doublesided, multi-layered DVDs have a capacity of 17 GB.

The speed of a DVD-ROM drive is given as a number, for example 16X. This is different from a CD, as each 1X is 1250 Kilobits per second.

DVDs are used in the same way as CD-ROMs but, since they can hold more data, they can also be used to store high-quality video.

DVD-R

DVD-recordable allows you to record data once. After recording the data cannot be changed. They have the same capacity as DVDs but a DVD-R drive has two speeds, one for writing and one for reading data, for example,

Write 6X, Read 12X.

DVD-RW

This is a DVD that allows you to record data over and over again. Like hard disks, you can use them to make backups of very large files, such as home movies from your digital video camera and you can change the data stored on the disk as often as you want.

A DVD-RW drive has three speeds; one for writing data, one for rewriting and one for reading, for example. Write 6X, Rewrite 2.4X and Read 12X.

Blue-Ray Discs

Blu-Ray discs are used in the same way as DVD-ROMs but, since they can hold more data, they are also used to store very high-quality, high-definition (HD) video.

Watch the video – “How do CD’s work”

“How (CD) Compact Discs Work”

9

Solid State

Solid State Capacity

USB Flash Drive

SSD Drive

1Gb-512Gb

256Gb

SD Card 1Gb-16Gb

The term ‘solid-state’ essentially means ‘no moving parts’.

The most common form of portable backing storage is the

USB flash drive. Also called pen drive or memory stick the flash drive shown in the photograph on the right is a small portable backing storage device with no moving parts.

This type of backing storage plugs into the USB port of a computer, making them a convenient way of keeping a backup copy of files and of transferring files from one computer to another.

Flash drives can store large amounts of data up to 512Gb.

Memory Cards

Mainly used in small electronic devices such as digital cameras, MP3 players and mobile phones, memory cards are usually read by connecting the device containing the card to the computer or by using a USB card reader. Memory cards are small, light and again have no moving parts. Despite the small physical size some types of memory card can hold many gigabytes worth of data.

In summary solid state storage devices are

• Re-writable

• Ultra-Portable (fits in your pocket)

• Good capacity size for transferring files such as large documents or photos.

Watch the video – “Explaining SD Cards”

“Explaining Solid State Drives”

“USB - Universal Serial Bus”

“Explaining USB 3.0”

10

Portable Hard Drive

A portable hard-drive is one that is placed into a small case along with some electronics that allow the hard-drive to be accessed using a USB or similar connection.

Portable hard-drives allow very large amounts of data to be transported from computer to computer.

Exercise

1.

Which of these is a backing storage device?

A

C

Scanner

Printer

B

D

Flash drive

Speakers

2.

3.

What type of access is used by a magnetic tape drive?

Use the internet to research the current cost and capacity of the backing storage media mentioned on the previous page. Put your findings into a table, sort the table from lowest value storage to highest value storage, print this list out and save your table.

5.

4.

Using the table created in question 3, perform another sort but this time for capacity in descending order from highest capacity to lowest capacity.

What is meant by the term ‘solid state’?

11

Input Devices

An input device is a piece of hardware that lets you put information onto or into a computer to be processed.

Digital Camera

This is a camera for taking digital pictures. The quality is measured in megapixels; the number of millions of detectors in the grid that detects the picture. A reasonably good one will be 16 megapixels and will cost less than £80. Advantages: they can hold lots of images without film, you can delete the pictures you don’t want, you can also transfer them to a computer and print them out easily.

Digital images can be taken of an event such as a birthday party and then be transferred to a computer, edited and shared online with others.

Microphone

Allows sound to be input to the computer. Microphones are used to take a sound and convert it into an electrical signal for the computer.

Recording narration for a video.

Used in conjunction with voice recognition software to give commands to the computer or to take the spoken word and convert to text on screen.

Joystick or Joypad

Joysticks or joypads are used mainly in games to give the user control over the game objects like a car, a plane or a human character.

Controlling a game using a joystick or joypad is much easier than using the keyboard and mouse.

Playing computer games

12

Webcam

Webcams are digital cameras that are used to take photographs. The photographs are then transferred to a web page and then sent across the

Internet.

Used to view traffic flowing along motorways and to advertise tourist attractions and business sites.

Touchpad

A small, flat pad which senses your finger movements and uses this to control the cursor on the screen and select icons and menus. More convenient for use with a laptop where it is difficult to use a mouse.

Similar to a mouse it can be used to select items from a menu or highlight objects on screen to be edited.

Scanner

Used to input images to a system. A light beam passes over the page or photo and a sensor detects the light being reflected, i.e. the light bits. This information is changed into binary values for light and dark and saved to a file.

Digitising a traditional photo on photo paper so that it can be edited and shared with others, for example on a website.

Mouse

A pointing device used to interact with graphical user interfaces on screen. The hand-sized case has at least one button on top and (usually a laser fitted underneath.

Sensors detect the movement of the mouse relative to the surface underneath,. The mouse is used to control the cursor on the screen and to manipulate icons and menus.

13

Keyboard

A normal keyboard has keys for the letters of the alphabet, keys to produce the digits from 0 to 9, keys to produce all punctuation marks and special command and function keys.

Typing an essay up in a word processor.

Typing in numbers/data for a sales spreadsheet.

Typing in a web address (URL) for a website.

Graphics Tablet

A graphics tablet is a flat pad with electronic sensors below the surface. These detect the movements of a pointing device (stylus) and move the cursor on the screen accordingly. What is drawn or written on the pad will appear on the screen.

This system has the advantage of being very sensitive and accurate and is used in engineering and design systems.

Output Devices

An output device enables a computer to communicate with the outside world.

Brief descriptions of some common out devices are given below.

LCD Screens

LCD screens use transistors and a thin film of liquid crystals to control the light passing through the screen. They are found on palmtops and laptops, smartphones and tablets because they are light, compact, need little power and can be run on batteries. One problem is that some LCD screens are not very bright and can cause eye strain if they are used for too long.

14

TFT Screens

TFT is a type of LCD screen that uses lots of transistors to produce a high quality display. A TFT screen can display animations and threedimensional graphics much more clearly than ordinary LCD screens. The disadvantage is that they can be a lot more expensive than ordinary LCD screens.

On desktop computers TFT screens are used because they take up less space on a desk than CRT, (cathode ray tube), monitors and less awkward to move around.

Inkjet Printer

Uses ink cartridges and sprays fine jets of ink onto the paper to form letters. Inkjet printers can produce high-quality printouts and are cheaper to purchase than laser printers.

However running costs can be high as the toner is expensive,

(and dries out if you don’t use it often). They are also a lot slower than laser printers.

Home use, to print off short letters or colour photos.

Laser Printer

A laser printer works by using a laser beam to put the image of a page onto a photosensitive drum. The toner or ink then sticks to the charge drum. This is then transferred to paper and fused by heat to make it stick. They are very fast and produce very high quality output. However, they can be more expensive to buy than an inkjet.

Business use to print out long documents or multiple copies of reports quickly.

15

How to Compare Printers

You compare printers using the following criteria:

Speed

This is measured in pages per minute (ppm), for example 8 ppm.

Resolution

The higher the resolution, the more dots per inch, (dpi), the better the quality of the printout. Printouts for a printer capable of 900 dpi will be poorer in quality than those from a

Cost

1200 dpi printer.

Capital cost: the initial cost of buying the printer. Running costs: the cost of toner or ink, (and paper).

Speakers

These are used for outputting sound; how loud the speakers are is generally measured in watts.

To provide sound for a multimedia presentation.

To allow the user to hear the dialogue in a DVD being played on the computer.

Graphics Card

These cards have on-board memory that is dedicated to handling graphics. This relieves the main CPU, allowing it to concentrate on other tasks. The graphics card takes digital information about the graphics stored in the RAM then sends it out to control the colours and refresh the image on the screen.

Allows a user to play high-quality, first-person, shooter games.

Allows a user to edit and produce high-definition video.

16

Sound Card

Similar to a graphics card, sound cards have on-board memory that is dedicated to handling sound, relieving the main CPU and allowing it to concentrate on other tasks. The sound card takes digital information about the sound stored in the

Allows a user to enjoy high-quality, immersive surround sound, whilst playing first-person shooter games.

Allows a user to edit and produce high-quality audio.

Exercise

1.

What does the L in LCD stand for?

A

B

C

D

Lighter

Links

Liquid

Laser

2.

What is the smallest measure of storage size?

A

B

C

D

Kilobyte

Megabyte

Byte

Bit

3.

Which of these is an input device?

A

B

C

D

Speakers

Monitor

Digital camera

Printer

4.

Which of these is an output device?

A

B

C

D

Scanner

Mouse

Keyboard

Monitor

17

Types of Computer

You need to know about the following devices:

• Supercomputer

• Desktop

• Laptop

• Tablet

• Smartphone

• Embedded

• Server

Mainframes and Supercomputers

These computers are very large physically, generally positioned in specially designed rooms with air conditioning, uninterruptable power supplies and enhanced physical and electronic security.

Mainframes are used for large organisations like banks to perform a high volume of important tasks simultaneously, whereas supercomputers are generally used by scientists to crunch massive amounts of data to perform a specific complex calculation, e.g. scientific research, medical research, forecasting the weather and modelling climate change. Both types of computer process data extremely fast and have massive amounts of memory, multiple powerful processors that allow a large numbers of users to access the system at once.

Desktop

These computers are not portable and are powered by mains electricity rather than by battery. A desktop will have a monitor, fullsized keyboard, mouse and optical DVD or blu-ray drive.

Laptop

A laptop:

• Is small enough to use on your lap comfortably

• Is useful for working away from the home or office

• Is light, weighing less than 4kg and can be carried easily

• Is powered by batteries, (or by mains adapter)

• Has an LCD or TFT screen

• Has standard keyboard and a touchpad as well as a range of disk drives.

Tablet

A tablet is a mobile computer with:

• a flat touch screen usually between 7 and

10 inches in size

• a screen resolution commonly around 1200 x 800

• a processor with a speed around 1.5 GHz

• memory capacity between 16 and 64 Gb

• a battery with a life of around 10 hours before recharging

• an Internet connection

Smartphone

A smartphone:

• Is a mobile phone with a memory to hold an address book and ring tones; and the ability to send, receive and store text messages

• Is a multimedia device that can handle text, graphics, audio and video

• Has a browser to access web pages and send email

• Has a digital camera to capture images and send them through the phone network and the Internet

• Can play MP3 files and games

• Can connect with laptops and desktops.

19

What is an Interface?

The interface is the combination of hardware and software needed to enable the processor in a computer to communicate with the external devices. You need an interface to connect your computer to external devices like a printer or an external hard drive or USB flash drive.

When looking at an interface it is important to consider the speed of data transfer, or how quickly data is sent to and from the device. The slower the interface speed the longer a user has to wait to copy or save files.

What does an Interface do?

An interface will do jobs like:

• change electrical voltages

• deal with control signals

• change analogue data to digital form

• store incoming data so that the processor can get on with other tasks.

Interface Type Transfer Rate

USB 2.0 480 Megabits per second

FireWire 800

Express Card

USB 3.0

SATA

Thunderbolt up to 800 Megabits per second up to 2.5 Gigabits per second up to 5 Gigabits per second up to 6 Gigabits per second up to 10 Gigabits per second

20

Exercise

1.

Which type of computer controls and distributes resources on a network?

A

B

C

D

A server

A tablet

A palmtop

A bottletop

2.

What type of computer might be used for a large and complex scientific project?

3.

Put the following devices in order of physical size with the smallest first: laptop, desktop, smartphone, tablet.

Activity: Device Investigation

Research each of the following:

• Desktop PC

• Laptop

• Tablet

• Games Console

• Smartphone

• Mainframe

Types of Computer System Research

Cost (£)

Processor

(GHz) RAM (Gb) Storage (Gb) Name

Apple iPad 3

Tablet £479.99 1 1 32

Dell Studio Laptop £399.44 2.4 4 500

Present your findings in a spreadsheet as shown above.

When you have got the information for each of the devices create a graph with the information for each piece of info (1 graph for cost, 1 for processor etc.).

Do you see any trends?

21

Operating System

Some people would say that the operating system is the most essential software on a computer system. The operating system is the first program to load up when a computer is powered up and contains a program or set of programs that control how the computer functions. Without an operating system installed the computer is just an expensive lump of metal and plastic.

Watch the video – “Computer Basics - The Operating

System”

Functions of an Operating System

The operating system carries out important functions on the computer. They:

• Manage the use of both the internal memory and backing store

• Manage the files and keep track of where they are stored in the system

• Provide the user with an interface usually a graphics-based interface, increasingly with a touch screen and even voice input

• Run other software

• Control the use of devices such as printers.

Exercise

1.

2.

Research and list as many operating systems as you can.

Swap your list from question 1 with another pupil, tick the ones you had on their list and add any others they didn’t have. Make a note of any names you didn’t have on your list and make sure to add them to yours.

3.

What must be taken into account when designing an operating system for smartphones and tablets?

22

Networking

Stand Alone or Networked

Most computer systems today are connected to a network most of the time or at least some times.

If a computer is not connected to a network it is called a stand alone

computer. Even though it is not connected to a network it will certainly have the capability to do so.

Scale of a Network

Networks can be categorised into two main types based on their scale or size.

There are Local Area Networks and Wide Area Networks.

Local Area Network (LAN)

A group of linked computers in close

proximity to each other, such as in an office building, a school or at home.

LANs are useful for sharing resources such as files, printers or other applications.

The computers can be linked using copper cables or by a wireless connection.

Watch the video – “What is a LAN (Local Area Network)”

23

Wide Area Network (WAN)

A WAN covers a large

geographical area, such as a city, county or country.

Most WANs are made from

several LANs connected

together.

The internet is a global network of networks where many LANs and

WANs are interconnected.

Internet

Watch the video – “What is a LAN and WAN”

The internet is a global system of interconnected computer networks.

24

• It has a number of different elements:

• The World Wide Web which is made up of multimedia web pages that are stored on computers across the world. Web pages hold text, sounds, graphics, animations and videos. These are linked by hyperlinks.

• Search engines to help users find their way around the Internet.

• Forums and chatrooms where you can meet people and discuss all sorts of topics.

The Internet has many uses, for example sending email, social networking,

(Facebook), Twitter), online shopping and banking.

Wireless

Wireless networking involves computers and devices communicating with one another without any cabling.

Wireless networks use radio waves, microwaves or infrared light to transmit data. All you need is a transmitter/receiver in every machine and a central device, such as a wireless router, to pass the data around the network.

Any modern computer can be fitted with a wireless network card, sometimes by just plugging it into the USB.

Advantages

Wireless networks are easy to install, as there is no need for cables. Also you can move around when you work without trailing wires. They have reasonably fast transmission speeds, although they can be slower than physical cables.

The main problem is that they are very vulnerable to hackers, who can just

‘tap in’ to your signal. You need to take care when setting up network security if you don’t want other to access your files or use you internet connection.

25

The downside to wireless networking is that the bandwidth or speed of transmission is generally slower than a wired connection.

Bluetooth is a wireless network technology that allows devices like mobile phones, printers, headsets and laptop computers to form mini-networks when they are in close proximity to each other.

Some businesses will use wireless as it saves money not having to lay down all the cable.

Wired Networks

Here are some types of wiring used on LANs

Twisted Pair

The most common type of networking cable is twisted pair or ethernet cabling. This cable consists of two copper wires twisted around each other. It is widely used because it is cheap and capable of transmitting data quickly, at speeds of 100 megabits per second.

Coaxial

This cabling is not so commonly used as it is more expensive. It is used where there if lots of interference that can corrupt data because it has a protective shield to prevent interference.

Fibre-Optic

26

Fibre-optic cable is made up of fine strands of glass that transmit data as pulses of light.

Fibre-optic cable transmits at very high speeds. It also doesn’t lose data because of interference and is very secure.

The downside to fibre-optic cabling is that, it is very expensive compared to twisted pair. You may have heard Virgin Media offering fibre optic broadband at speed of up to 100Mbps.

Types of Networks

A network is two or more computers connected together.

Networks commonly consist of a server computer that manages the network, and clients for users to connect to the network. These are known as client/server networks

Servers are special computers on a network that manage the running of the network resources; clients are any computers that can access the network.

The other kind of network examined in this course is a peer-to-peer network.

Peer-to-peer networks consist of between two and five computers connected together. Peer-to-peer networks don’t have the expense of a dedicated server. All machines on the network have equal status, with no one machine having any controlling role. Machines can share resources such as printers, folders on hard disks and an internet connection, but security and backups are more difficult to implement than they would be on a client server network. This kind of system works best in a home or small office.

27

Advantages of Networks

Networks allow users to share data and programs. Data stored on one computer can be made available to all computers on the network. This saves time because files do not have to be individually placed on every single computer on the network. Also, parts of programs can be stored centrally on a server which saves storage space on the client computers.

Peripherals can be shared more easily on a network. Some expensive hardware, such as colour laser printers, can be shared using a network.

Instead of buying a printer for each individual workstation one fast printer can be bought and shared by the clients.

A big advantage of networks is that clients can easily communicate electronically with other clients on the network.

Peer to Peer V Client/Server

Client Server

Client/Server is a network where there are two levels of computers: servers and clients.

The server stores and manages access to files and data on a file server.

There may also be a print server which manages printing on the network by storing a queue of files to be printed.

Advantages

• All data is stored in one central location (easy to backup)

• Software is installed once on the file server and then made available to clients

28

• Good security as there can be different level of access rights with each user

• Good for businesses and organisations

Peer to Peer

In a peer to peer network there is no centralised server managing the network. In this type of network there are a small number of computers of equal status connected together to share resources such as printers and to access the files on each others hard discs, or carry out key operations such as validating users.

Disadvantages

• Backing up data is difficult as there is no central server where it is installed in one location

• All software has to be installed separately on each individual computer.

• Security is difficult to implement as there is no way to centrally control access to the network

• Best used in a trusted environment such as at home.

Local Storage

Backing up locally means to use your own media, such as an external hard drive or CD, to store extra copies of your data. This is often the most

affordable way to backup large amounts of data.

Advantages

• You have 100% control over the data.

Very affordable, especially for large amounts of data. External hard drives come quite cheap these days.

No internet connection required.

Disadvantages

• It’s not always very easy or convenient to find room to store your external media.

• Just like your primary hard drive, external media

can fail as well.

Possible theft

• No data access on-the-go unless you bring the media with you which might be too bulky.

However, flash drives may work well.

Cloud Storage

29

Cloud storage is quickly gaining popularity with events such as the introduction of Chrome OS, an operating system that is completely online.

Cloud storage means to store data online. Cloud computing involves renting computer storage and power from large multinational companies with special facilities. With cloud computing, the user accesses data and applications over the internet from their supplier rather than from the backing storage of the local computer or device that is currently being used.

The advantages to this are many but include the convenience to the user of always being able to access their data wherever they are as long as they have an internet connection and the added security of the user data being stored safely and securely on a state-of-the-art server.

Advantages

• Some services offer a basic free version, such as Dropbox (2 GB) and

SkyDrive (25 GB)

Available anywhere there’s an internet connection without having to carry anything extra

Third parties handle taking care of the hardware and security so no worries about storing external media in a safe place

Disadvantages

Internet connection required. In addition, a relatively fast connection is recommended for the uploads and downloads to work well.

• Depending on a third party that you have no control over. They can technically do whatever they want with your files. Be sure to read their terms and privacy policies.

• The third party might randomly shut down due to financial hardships or other unforeseen circumstances.

• Just like your primary hard drive, the hardware third parties are using can fail at any time.

• Often can be more expensive if you need to store

large amounts of data. Free services usually only offer a maximum of a few gigabytes.

Watch the video – “What is Cloud Storage”

30

Exercise

1.

When two computers are linked together it is called:

A

B

C

D the world wide web the internet a server a network

2.

A server controls:

A

B

C

D switching on a computer the running of a network switching off a computer the running of computers

3.

A network with a small geographical spread is called:

A

B

C

D a LAN the internet a WAN the world wide web

4.

Name two advantages of setting up a network.

31

5.

Name two types of wireless network technology.

6.

Name two kinds of network media.

Activity: iTunes, iCloud & Apple

In this activity you are going to be assessed on your knowledge of hardware and software requirements, storage and connectivity.

1. Open the file “

iTunes iCloud Report

” from the shared area.

2. Work your way through the questions answering in sentences showing your understanding.

32

Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement