GCSE ICT Revision

Hardware

2006-12-03T15:16:00.001Z

What is Hardware?

Hardware is the physical parts of the computer, that is the parts you can touch. You can arrange hardware into a number of different catergories; Input Devices, Output Devices and Storage Devices.

Input Devices

Input devices allow us to enter raw data into a computer. There are a large variety of different devices however there are a number of commonly used ones;

A Keyboard - including concept keyboard.

This is a flat board that contains a grid of buttons. Each button can be programmed to follow instructions. An overlay sheet is placed on the grid with an explanation for each button. They are used in primary schools with young children. Many modern fast food restaurants have overlays with either a description or picture of the meals that are available to make ordering easier.

A Mouse

A mouse is the most common pointing device that you will come across. It enables you to control the movement and position of the on-screen cursor by moving it around on the desk.
Buttons on the mouse let you select options from menus and drag objects around the screen. Pressing a mouse button produces a 'mouse click'. You might have heard the expressions 'double click', 'click and drag' and 'drag and drop'.
Most mice use a small ball located underneath them to calculate the direction that you are moving the mouse in. The movement of the ball causes two rollers to rotate inside the mouse; one records the movement in a north-south direction and the other records the east-west movement. The mouse monitors how far the ball turns and in what direction and sends this information to the computer to move the pointer. Other pointing devices are the tracker ball and the touch pad (as found on a laptop computer).

The Data Protection Act

2006-11-15T20:22:00.000Z

Introduction

Many organisations store large amounts of personal information about people on their computer systems. This may be data on customers, employees, suppliers, competitors, etc.

The increasing trend to store vast quantities of such data has worried many people.

Some of their concerns are:

Who will be able to access this data? Will information about me be available over the Internet, and therefore vulnerable to hackers? Can my records be sold on to someone else?
Is the data accurate? If it is stored, processed and transmitted by computer, who will check that it is accurate? People often think it must be true if 'it says so on the computer'.
Will the data be sold on to another company? For example, could my health records be sold to a company where I have applied for a job? Could my personal details, collected by my employer, be used by a commercial company for targeting junk mail?
Will data about me be stored even if it is not needed?

In order to address these concerns, the Data Protection Act (1998) was passed.

Key Terms

Data Subject - This is the person that the data is being collected from or stored about. This could be you!

Data User - This is any person who needs to access or use the data as part of their job. This could be a secretary who needs to look up your address so that they can send a letter home, it could be a personnel officer who needs to know the medical history of an employee who regularly takes time off sick.

Data Controller - This is often the person in charge of the organisation - but it doesn't necessarily have to be. This person decides what data the organisation needs to collect and what it will be used for. This is the person who must apply for permission to collect and store data in the first place.

Data Commissioner - This is the person who enforces the Data Protection Act. This is the person that organisations need to apply to in order to gain permission to collect and store personal data.

Personal Data - Personal data covers both facts and opinions about a living individual. Facts would include name, address, date of birth, marital status or current bank balance. Results in examinations, details of driving offences, record of medications prescribed and financial credit rating are further examples of facts that could relate to an individual. Personal opinions such as political or religious views are also deemed to be personal data.

The 8 principles of the Data Protection Act

Data Controllers must ensure that their organisation follows the eight principles of the Data Protection Act when dealing with personal data.

1. Personal data should be obtained and processed fairly and lawfully.
This means that you should be told that data is being collected about you, and you should know what the data will be used for.

2. Personal data can be held only for specified and lawful purposes.
The Data Controller has to state why they want to collect and store information when they apply for permission to be able to do so. If they use the data they have collected for other purposes, they are breaking the law.

3. Personal data should be adequate, relevant and not excessive for the required purpose.
Organisations should only collect the data that they need and no more. Your school needs to know your parent's phone number in case they need to contact them in an emergency. However, they do not need to know what your grandmother's name is, nor do they need to know your eye co lour. They should not ask, nor should they store such details since this would be excessive and would not be required to help with your education.

4. The personal data should be accurate and kept up-to-date.
Companies should do their best to make sure that they do not record the wrong facts about a data subject. Your school probably asks your parents to check a form once a year to make sure that the phone number and address on the school system is still correct.
If a person asks for the information to be changed, the company should comply if it can be proved that the information is indeed incorrect.

5. The personal data should not be kept for longer than is necessary for the purpose for which it is collected.
Organisations should only keep personal data for a reasonable length of time. Hospitals might need to keep patient records for 25 years or more, that is acceptable since they may need that information to treat an illness later on. However, there is no need for a personnel department to keep the application forms of unsuccessful job applicants.

6. Data must be processed in accordance with the rights of the data subjects.
People have the right to inspect the information held on them (except in certain circumstance - see later). If the data being held on them is incorrect, they have the right to have it changed.

7. Appropriate security measures must be taken against unauthorised access.
This means information has to be kept safe from hackers and employees who don't have rights to see it. Data must also be safeguarded against accidental loss.

8. Personal data cannot be transferred to countries outside the European Union unless the country provides an adequate level of protection.
This means that if a company wishes to share data with an organisation in a different country, that country must have similar laws to our Data Protection Act in place.

Sensitive Data

The Act mentions specific things which it deems to be sensitive or personal to an individual. If a company was to collect this data, it cannot be disclosed or told to anyone else.

Some things which are classed as Sensitive Personal Data are:

racial or ethnic origin
membership of a trade union
criminal convictions or offences
political opinions
religious beliefs
mental or physical welfare.
the commission or alleged commission by them of any offence.

Under some circumstances, it may be necessary to collect this information. For example, the police force will need to know if new recruits have any previous criminal convictions.

Your rights

Under the sixth Data Protection principle, data subjects have the right to:

see data held on themselves. They must apply in writing and pay a small fee (often around £10). The company must respond to the request within forty days.
have any any errors corrected.
claim compensation for any distress caused if the Act has been broken.
prevent processing likely to cause damage or distress.
prevent processing for direct marketing by writing to the data controller to inform them that advertising material is not to be sent.
prevent processing for automated decision taking by writing to the data controller to inform them that no decisions should be taken based on automatic processing. Some banks determine whether or not a customer should be given a mortgage on the basis of a computer program. The data subject has the right to prevent that happening

Exemptions in the Data Protection Act

Not everyone is automatically entitled to see the data which is held on them. There are certain circumstances under which data controllers are exempt from providing information to data subjects.

These are:

National Security: If required for the purpose of safeguarding national security, data controllers do not have to disclose the data held to data subjects.
Crime: Data which is being held in order to prevent or detect a crime does not have to be disclosed.
Taxation: any data collected for taxation purposes is exempt
Heath, Education and Social Work
Personal data about the physical or mental health of the data subject. You have no automatic right to view your medical records. If a doctor believes that viewing them would harm your mental well being, they can be withheld from you.
Personal data relating to the present or past pupils of a school.
Examination scripts and examination marks held by examination authorities
Personal data being processed by government departments or local authorities which is being used in the course of any investigation or monitoring.
Personal data that could form part of a confidential reference (application for employment or a college course etc) is also exempt from access. This means that you have no legal right to ask to see a confidential or personal reference about yourself

Copyright

2006-11-09T11:57:00.000Z

Computer users must follow the copyright law which also applies to other media such as videos, music cassettes and books.

Copyright law

Computer users must obey the copyright law. When you buy software:

you do not have the right to give a copy to a friend.
you cannot make a copy of the CD with a CD writer and then sell it.
you cannot use the software on a network unless the licence allows it.
you cannot rent out the software without the permission of the copyright holder.

Software companies take many steps to stop software piracy:

The licence agreement is normally part of the installation process and you have to press ‘ok’ or ‘I agree’ to be allowed to install the software. This applies equally to downloaded software.
You are usually asked to type in a licence key which is a set of letters and numbers, when you install the software.
Some programs will only run if the CD-ROM is in the CD drive.
Some programs will only run if a special piece of hardware called a dongle is plugged into the back of the computer.

FAST

The Federation Against Software Theft (FAST) was founded in 1984 by the software industry and is now supported by over 1,200 companies. It is a not-for-profit organisation aiming to prevent software piracy and has a policy of prosecuting anyone found to be breaching copyright law.

FAST also works to educate the public about good software practice and legal requirements.

Viruses

2006-11-09T11:27:00.000Z

A virus is simply a program designed to cause harm to someone else's computer. A virus spreads by duplicating and attaching itself to other files. The extent of the damage depends on the virus. There are tens of thousands of viruses.

Some virus damage is insignificant but inconvenient. Some virus damage is disastrous, putting the computer system out of action by crashing memory, erasing files or corrupting data.

How do you catch a virus?

Viruses are written by malicious programmers who wish to cause problems to other computer users.

The primary source of infection these days are e-mail attachments followed by illegal software and infected files from the Internet. Also, by putting an infected floppy disk into your computer - the virus can automatically copy itself from the infected disk into your computer

If you have up to date anti virus software installed this will immediately warn you of any infection. If not, there is usually no evidence of the virus and the user is not usually aware of it until something goes wrong.

How can they be prevented?

Viruses can be prevented by taking sensible precautions, including:

using up to date anti virus software. E-mail attachments are now the biggest source of virus
spread and many e-mail servers are now installed with anti-virus software.
not allowing other users to use their own floppy disks on your system
not allowing users to take the company's disks home to use on their own PC
only downloading files from reputable Internet sites
write-protecting disks
avoiding software from unreliable sources
backing up data regularly

Anti-virus software can inspect computer files and e-mail attachments for viruses and remove or quarantine any which are found.

Other problems

As the internet has grown and millions of people are online, so has the development of other types of software pests. These include:

Trojan software. This is an application that appears to do something useful such as a computer game (which is why you loaded it on to your computer in the first place) but quietly, behind the scenes it is doing something with ill-intent. A trojan may:-

Log all your keystrokes and then send the details to a remote computer / server. Used to capture your passwords
Allow someone else to take control of your computer whilst you are online.
Capture screenshots and send them to a remote computer, once again with the intent of obtaining confidential information such as financial screenshots.

Worms. These are a bit like a computer virus but they spread on their own through compuer networks. Their biggest problem is the sheer amount of computer time and bandwidth they soak up, so making the network slow to a crawl.

Adware / Spyware: These are programs designed to keep track of which adverts you click on and then they send specific adverts to your browser. Fairly harmless but annoying and hard to get rid of.

The Computer Misuse Act

The Computer Misuse Act (1990) made three new offences:

accessing computer material without permission e.g. looking at someone else's files
accessing computer material without permission with intent to commit further criminal offences e.g. hacking into the bank's computer and increasing the amount in your account
altering computer material without permission e.g. writing a virus to destroy someone else's data

Writing a virus or deliberately spreading one is illegal.

Health and Safety

2006-11-06T09:29:00.000Z

There are various health problems associated with the regular use of computers, and because of this employers must be aware of the regulations surrounding computer health and safety.

Employer regulations

The law states that an employer must:

Provide tiltable screens
Provide anti-glare screen filters
Provide adjustable chairs
Provide foot supports
Make sure lighting is suitable
Make sure workstations are not cramped
Plan work at a computer so that there are frequent breaks
Pay for appropriate eye and eyesight tests by an optician

Note: These regulations apply only to offices - not to students or pupils in schools or colleges.

In order to provide the satisfactory equipment for their employees, employers use ergonomics to assist the equipment design process. It is the science concerned with designing safe and comfortable machines for humans. This includes furniture design and the design of parts of the computer like keyboards.

General working environment

Don't forget that rules for all electrical appliances apply in a computer room. This means:

There should be no trailing wires
Food and drink should not be placed near a machine
Electrical sockets must not be overloaded
There must be adequate space around the machine
Heating and ventilation must be suitable
Lighting must be suitable with no glare or reflections
Benches must be strong enough to support the computers

Possible dangers and solutions

Within Information Technology it is important that people have an awareness of the various health and safety issues. Steps should also be taken towards preventing common problems rather than trying to cure them at a later date.

Back problems

Many computer users suffer serious back problems. This is probably due to a poor posture or an awkward position while sitting at a computer.

Solutions

A fully adjustable chair should avoid poor posture
Footrests can reduce these problems
Screens should tilt and turn to a position that avoids awkward movements

Repetitive Strain Injury (RSI)

Repetitive Strain Injury (RSI) is damage to the fingers, wrists and other parts of the body due to repeated movements over a long period of time.

Solution

To prevent RSI, make sure your posture is correct, use wrist rests and have a five-minute break from typing every hour.

Eyestrain

Eyes can become strained after staring at a computer screen for a long time, particularly if working in bad light, in glare or with a flickering screen.

Solutions

Screen filters can remove a high percentage of the harmful rays emitted from a computer screen
Use screens that do not flicker
Take regular breaks - do not work for more than one hour without a break
Lighting must be suitable and blinds fitted to windows to reduce glare

Ozone irritation

Health experts have suggested that ozone emitted from laser printers can lead to breathing problems.

Solution

It is recommended that laser printers should be situated at least one metre away from where people are sitting and there should be good ventilation in the area.

Network Topologies

2006-11-03T15:01:00.000Z

The way networks are arranged is called a network topology. Networks can be a single topology or a mixture of more than one. Whatever the topology, each computer has to have a network address so that the packets of data know where to go. This is known as IP address, an example would be 192.168.0.128.

There are three basic types of network topolgy: Bus, Ring and Star.

Bus Network

This is the simplest way to connect workstations, servers and other components of a network by using a single cable. One or more of the workstations act as the File Server, whilst the other machines are used as workstations or terminals.

Advantages:

Cheap
Easy to install.

Disadvantages:

If there is a problem with the cable, the entire network stops working.
If many workstations are using the network at the same time, response can be very slow, thus frustrating users who want to work quickly. The technical term for data trying to travel simultaneously along the cable in different directions is called 'data collision'. A busy network will have many data collisions.

Ring Network

The workstations are attached to a cable arranged in a ring

Advantages:

Very fast - all data traffic occurs in the same direction so there should be no data collisions.

Disadvantages:

If a single machine is switched off then the network does not work. If the cable breaks, once again, the network does not work.

Star Network

Each workstation has its own direct line to the server. Connections to the server are made with hubs or switches.

Hubs connect many lines together.

Switches allow the network manager to connect certain workstations to specific servers.

Advantages:

Reliable - if one connection fails, it does not affect others.
Good performance, fewer data collisions as each workstation has its own line.
Good Security - no workstation can interact with another without going through the server first.

Disadvantages:

Expensive to install - lots of cables required.
Installation is an expert job.
Extra hardware required such as hubs, switches and wiring centres.

Star networks are normally preferred because of their reliability.

Networks

2006-11-03T12:02:00.000Z

A computer network is a number of computers linked together to allow them to share resources.

Networked computers can share:

hardware - such as a printer
software - they may be able to load up the same program
data - they can load up the same files

LANs and WANs

There are two types of network: LAN and WAN.

A LAN is a Local Area Network covering a small area such as one building e.g. in a school or a college.

A WAN is a Wide Area Network covering a large geographical area.

The Internet is a WAN.
A network of bank cash dispensers is a WAN.
A school network is a LAN. LANs are often connected to WANs, for example a school network could be connected to the Internet.

Telephone lines are often used to connect WANs. LANs use dedicated cables or wireless technology.

Advantages and disadvantages of networks

Advantages

Sharing devices such as printers saves money.
Site licences are likely to be cheaper than buying several stand-alone licences.
Files can easily be shared between users.
Network users can communicate by email.
Security is good - users cannot see other users' files unlike on stand-alone machines.
A file server is easy to back up as all the data is stored in one place.

Disadvantages

Purchasing the network cabling and file servers can be expensive.
Managing a large network is complicated, requires training and a network manager usually needs to be employed.
If the file server breaks down the files on the file server become inaccessible. E-mail might still work if it is on a separate server. The computers can still be used as stand alones.
Viruses can spread to other computers throughout a computer network.
There is a danger of hacking, particularly with wide area networks. Security procedures are needed to prevent such abuse.

Microsoft names Vista launch day

2006-11-03T11:58:00.000Z

Microsoft has announced the date on which Windows Vista will be made available to businesses.
From 30 November corporate customers of the software giant will be able to get their hands on the next version of the operating system.
Also on that date Microsoft will make available Office 2007 - its suite of business programs.
Home users will have to wait until January 2007 to get hold of a copy of the Vista software.
Opening Windows
Vista is the long-awaited update of the Windows operating system that was originally slated to be released in August 2006. The software has been under development for more than five years. The release will be a simultaneous global launch.
Click here to see hardware checklist
The software is a major overhaul of Windows and updates many of the core technologies. New elements include improved security, an improved 3D interface, plus new sound and networking technologies.
Vista, known as Longhorn during its gestation, will be available in six separate versions to match the differing needs of computer users.
Three of these are tuned for businesses, two are for home users and one will be for developing nations.
Microsoft has yet to give details of the prices of the different versions but it has released information about what PCs will have to do to run the software. Many PC makers are now selling "Vista-ready" computers.
In the US the software will be unveiled by Microsoft boss Steve Ballmer at an event at the New York Stock Exchange.

Welcome

2006-11-02T23:35:00.000Z

Welcome to the new GCSE ICT Revision site. We hope this area will be of interest to you and that it will also prove to be useful. We will attempt to add relevant articles and revision notes to help with your preparation for your exams.