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A network is a series of computer systems that are linked together so that they are able to share
computing power or storage facilities. The link may be between computers in the same building or
between computers in different parts of the country or even in different parts of the world.

4.1 Networks:
4.1.1 Network devices:
Modems
A modem (modulator demodulator) is a device that converts a computer’s digital signal into an
analogue signal for transmission over an existing telephone line and back again.
Dial-up modems operate at transmission speeds of about 60 kilobits per second, which is extremely
slow.
Modem broadband or ADSL (asymmetric digital subscriber line) modems operate at up to 100
Mbits/second when using fibre-optic cables and 20 Mbits/second when using copper cables. ADSL
modems allow telephone conversations and internet traffic to occur at the same time because of the
of the wide bandwidth signal used.
Cable modems allow cable television providers to offer internet access as well as receiving
television signals.
Hubs:

A hub is a device that can have a number of other devices or computers connected to it to
form a LAN. It does not read any of the data in the packets which arrive from a computer, but just
sends them on to all the computers on the network, including the one that sent it. Using a hub is not
a very secure or efficient method of data distribution.

Switches:
Switches connect a number of devices together to form a LAN. Switches are
able to look at a data packet, target the computer for which it is intended, and send it. This helps to

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speed up data transmission in a network. Each device has a media access control (MAC) address
which identifies it uniquely. Data packets sent to switches will have a MAC address identifying the
source of the data and additional address identifying each device that should receive the data.

Bridges:
Bridges are devices that connect one LAN to another LAN that uses the same protocol. A large
network can get very busy. A bridge allows a large network to be segmented and stops unnecessary
traffic being passed around the network.

Routers:
Routers enable data packets to be routed between the different networks to join a LAN to a WAN.
Broadband routers sit behind a firewall.
The router’s main function is to transmit internet and transmission protocols between two networks
and allow private networks to be connected together.
Packets of data contain the following information:
• header to identify the data packet
• the sender’s IP address
• the receiver’s IP address
• how many data packets make up the whole ‘message’  the identity number of each packet

When a router receives a packet of data, it checks the destination IP address against the stored
routing table. The routing table stores the MAC address of the device, the assigned IP address and
the lease time the IP address is assigned for. The bits forming the destination IP address in the data
packet are used to point to the correct route. The packet is sent to a number of routers until it
reaches its final destination.

Other hardware Gateways:

A gateway is a network point (or node) that acts as an entrance to another network. If a network
node needs to communicate outside its network, it needs to use a gateway.

Network Interface Card (NIC):

The NIC enables the computer to link to the cable or to radio waves used to communicate across the
network. It is usually part of the device and contains the MAC address.

Network cables
Network cables have the following advantages over Wi-Fi:
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• faster data transfer rates
• can be more secure than wireless networks.

4.1.2 Internet Protocol (IP) and Media Access Control (MAC) addresses:
Each device on the internet is assigned for each internet session by the ISP a unique address known
as IP address.
The IP address gives the location of a device on the internet whereas the MAC address identifies the
device connected to the internet.

4.1.3 Wi-Fi and Bluetooth:

Wi-Fi:
A wireless transmitter (WAP) receives information from a network via its connection (e.g. a
broadband connection if the internet is used). This transmitter converts the received information
into radio waves and then transmits them.
A device (e.g. a computer) receives the radio waves via an installed wireless adaptor which allows it
to download the information from the data source.
A Wi-Fi enabled device can access the internet wirelessly at any access point (AP) or hotspot up to
100 m away.

Bluetooth:
Bluetooth sends and receives radio waves in band of 79 different frequencies (known as channels).
Devices using Bluetooth automatically detect and connect to each other. Each communicating pair
uses different channel.
Bluetooth creates a secure Wireless Personal Area Network (WPAN) based on key encryption.

Uses of Bluetooth:
• when transferring data between two or more devices that are very close together (<30 meters
distance)
• When the speed of data transmission is not critical
• For low-bandwidth applications (for example, when sending music files from a mobile phone to
a headset).

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Features Bluetooth Wi-Fi

Transmission frequency used 2.4 GHz 2.5, 3.6, 5.0 GHz
Data transfer rate (maximum) 25 Mbits/second 250 Mbits/second
Maximum effective range (meters) 30 m 100 m
Maximum number of devices Up to 7 Depends on the router used
connected

4.1.4 How to set up and configure a small network:

• Purchase of software and hardware (switches, network cables, a router, a firewall, servers, etc)
• Set up an IP account if internet access is required
• Set up the system to allow wireless connectivity
• Configure all the hardware and software
• Ensure a high-speed broadband connection exists
• Put the common software onto a server and ensure that the network licence allows network users
to use the software
• Set up privileges so that each user can only access their own area or common shared area
• Set up a network-manager-level of privilege to monitor network usage, change passwords, etc.

4.1.5 Internet, Intranets and extranets:

Internet:
The Internet is an international network of computers that allows users to use email, browse the
World Wide Web or to chat either by text or by voice.
The world wide web (WWW or web) is the part of the Internet which the user can access by way of
a web browser. A web browser is a software that allows the user to display and interact with pages
and files from the web. To find anything you need the help of a program called a search engine
which searches incredibly quickly through the Internet to find websites that contain information
about what you have asked for. The website shows hyperlinks to allow users to navigate between
webpages.

Each webpage has a unique address that helps web browsers to find them. The address is known as
the Uniform Resource Locator (URL).

Internet service provider (ISP)

An ISP is a company that provides users with access to the Internet, usually for a fee.

There are three common ways of accessing the internet offered by service providers:
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• dial-up access
• cable internet access
• digital subscriber line (DSL) (broadband) internet access.

Intranet:
Many companies use an Intranet as well as the Internet. An Intranet is ‘a computer network based
on internet technology that is designed to meet the internal needs for sharing information within a
single organisation.

Intranets reside behind a firewall and are only accessible:

• internally to members of the company, or
• to people given various levels of access who are external to the company.

There are a number of reasons for adopting Intranets rather than using the Internet:
• It is safer since there is less chance of external hacking or viruses.
• It is possible to prevent employees from accessing unwanted websites
• Companies can ensure that the information available is specific to their needs.
• It is possible to create extranets that allow intranets to be extended outside the organisation but
with the same advantages as an intranet.

It is now worth comparing the Internet with Intranets:

• The term ‘Internet’ comes from the phrase International Network.
• The term ‘Intranet’ comes from the phrase Internal Restricted Access Network.
• An Intranet is used to give local information relevant to the company whereas the Internet
covers topics of global interest.
• It is possible to block out certain Internet sites using an Intranet. This is much more difficult to
do from the Internet.
• An Intranet requires password entry and can only be accessed from agreed points, whereas the
Internet can be accessed from anywhere provided the user has an ISP account.
• An Intranet is behind a firewall, which gives some protection against hackers, viruses and so
on. This is much more difficult to do with Internet access since it is more open on an
international scale.
• The Internet can be public access, whereas Intranets tend to be private access.

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4.1.6 LANs and WANs:

Local Area Networks (LANs):
These systems are usually within one building. Computers and devices are connected to hubs or
switches.
Advantages:
1. Sharing of resources (such as expensive peripherals and applications software).
2. Ease of communication between users.
3. A network administrator to control and monitor the network (e.g. change passwords, monitor
internet use, etc.).

Disadvantages:
1. Easier spread of viruses.
2. Printer queues can be frustrating.
3. Slower access to the internet.
4. Increased security risks when compared to stand-alone computers.
5. If the main server breaks down, the network will no longer function.

Wireless Local Area Networks (WLANs):

A WLAN behaves like a LAN but has no wires or cables. This gives users the mobility to move
around within a broad coverage area and still be connected to the network.
Because of the limited range, most commercial LANs need several Aps.
Advantages:
1. All computers can access the same resources such as printers from anywhere within range of the
Aps.
2. As there is no cabling there is a safety improvement and increased flexibility.
3. Adding new computers and devices is easy and the cost is reduced since extra cabling isn’t
needed,

Disadvantages:
1. Security can be a big issue since the signal can be picked up.
2. There may be problems of interference, which can affect the signal.
3. The data transfer rate is slower than in wired LAN.

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Wide Area Network s (WANs):

The computers and terminals forming part of the network can be spread around the world. External
communication links such as satellites, microwaves or telecommunication links are used to connect
the network. The connection must normally be paid for because the links are external.

4.1.7 Accessing the Internet:

Mobile phones and tablets:
Advantages of using mobile phones:
• Very portable
• A person is more likely to have a mobile phone all times
• It is easy to use a mobile phone while on the move

Disadvantages of using mobile phones:

• Expensive to use if Wi-Fi hot spot not available
• The displays on mobile phones are smaller than on other devices
• Keyboards are very small
• Not all websites are mobile-friendly
• Signal less likely to be as stable or reliable as wired system

Laptops and Desktop computers:

• The screen size of laptops is usually bigger than a mobile but it is not usually as large as that on a
desktop computer.
• Laptops and desktops require expensive dongles to access phone networks.
• Processors used in laptops are not usually as powerful as those in desktops, so access speed is not
as quick.
• Laptops are more mobile than desktops but heavier and less portable than tablets or mobile
phones.
• Touchpads on laptops are not as easy to use as a mouse when navigating web pages, but much
easier than mobile phones.
• The keyboards on laptops are not as easy to use as a desktop but are much better than those on a
mobile phone.
• Desktops usually have a more stable and reliable Internet connection since they use a wired
system rather than Wi-Fi.

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4.2 Network issues and communication:

4.2.1 Network Security:
Should the internet be policed?
Arguments is favour of some form of control
• It would help to prevent illegal material being posted on websites.
• Most of the information can be found in books but it is much easier to find the information using
a search engine.
• It would prevent children being subjected to undesirable websites.
• It would help to stop incorrect information being published on websites.

Arguments against some form of control

• Material published on the internet is already available from other sources.
• It would be very expensive to 'police' all the websites.
• Policing can go against freedom of information.
• It would be difficult to enforce rules on a global scale.
• Laws already exist to deal with those who post illegal material/comments on websites.

Reliability of Information from the Internet:

√ Information is more likely to be up to date than in books, since websites can be updated very
quickly.
√ It is much easier to get information from websites using search engines.
√ There is a vast amount of information on the Internet. x Information on the Internet may be
incorrect, inaccurate or even biased since it does not go through any checking process.
x It is possible to get thousands of hits, which may make it difficult to find the information relevant
to the user’s search.

Undesirability of certain websites

• There is a risk of finding undesirable websites.
• There is a risk doubtful websites which are not genuine and could lead to a number of problems
such as undesirable web links, security risks, etc.
• Security risks are a very large problem.

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Security issues:
Ways of protecting passwords:
• Run anti-spyware software
• Change passwords regularly
• Passwords should not be easy to guess. Strong passwords should contain: o at least one capital
letter o at least one numerical value o at least one other keyboard character (such as @, &)

4.2.2 Authentication:
Authentication is used to verify that data comes from a secure and trusted source. It works with
encryption to strengthen internet security.
Some forms of authentication include:
 user IDs and passwords

• digital certificates
A digital certificate is a pair of files stored on a user’s computer – these are used in the security
of data sent over the internet. Each pair of files is divided into a public key and a private key.

• biometrics
Biometrics relies on certain unique characteristics of human beings; examples include:
fingerprint scans, signature recognition, retina scans, iris recognition, face recognition, voice
recognition.

• magnetic stripe cards - contactless cards - ID cards with holographic image

Many passports contain an RFID tag/chip, a photograph and a holographic image.

4.2.3 Viruses:
A virus is a self-replicate program that corrupts a computer system. A virus attaches itself to files,
leading to:
• computer crashes
• loss of files - system files when lost computer malfunctions.
• corruption of the data stored on files.

Antivirus software:
• they check software or files before they are run or loaded on a computer.
• antivirus software compares a possible virus against a database of known viruses.

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• they check software for types of behaviour that could indicate a possible virus (heuristic
checking)
• any possible files or programs that are infected are put into quarantine.
• antivirus software needs to be kept up to date.
• Full systems checks need to be carried out regularly.

Avoiding viruses when accessing the internet

• Avoid unknown or suspicious-looking websites.
• Look for security indicators such as https or the padlock symbol.
• Don’t open emails from unknown sources.

Viruses from hardware devices:

It is possible to pick up viruses from any device plugged into your computer.

4.2.4 Data Protection Act (DPA):

1. Data must be fairly and lawfully processed.
2. Data can only be processed for the stated purpose.
3. Data must be adequate, relevant and not excessive.
4. Data must be accurate.
5. Data must not be kept longer than necessary.
6. Data must be processed in accordance with the data subject’s rights.
7. Data must be kept secure.
8. Data must not be transferred to another country unless they also have adequate protection.

4.2.5 Network Communication: Emails

and Faxes:
Electronic mail is a method of sending messages from one terminal to another via a
communication link.
Advantages of using e-mail:
1. Message sent instantaneously.
2. The same message can be sent to many recipients at the same time.
3. No need to leave house to send e-mail.
4. E-mails can be read from any location.
5. Replies to e-mails are quick.
6. Can send file attachments.
7. Low cost, since stamps, paper and envelopes are not needed.

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Disadvantages of using e-mail:
1. Spam forms 85% of all e-mails in the world.
2. Might pass on viruses.
3. Cannot send physical objects.
4. Have to have a computer with an Internet connection.
5. Cannot send original of signatures.

Faxes (Facsimile): i)
Physical fax:
A fax machine is like a long distance photocopier. The document is put into the fax machine at one
end and a copy comes out of a fax machine at the other end. The original is first scanned with a
beam of light and then converted into electronic signals that can be passed along telephone lines.
ii)
Electronic faxing:
Electronic faxing makes use of computer technology and the internet.

Comparison of traditional faxes and emails:

Traditional faxes:
• Can be seen by anyone in the company.
• Signatures on faxes are accepted legally.
• If the telephone line is busy a fax cannot be sent.
• Slow process if several documents are to be sent, since each document needs to be scanned
before it is transmitted.

Emails:
• More secure than faxes because password protected.
• No need to print the document so saving cost and environmentally friendly.
• The document is usually of a better quality
• Documents received in emails can be modified
• It is much easier to send to multiple recipients at the same time
• People are more likely to have access to email accounts than a fax machine

Video conferencing is a communication method that uses both video and sound. It is carried out in
real time and makes use of some form of network. The basic hardware includes:

Hardware needed:
• Microphones
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• Web Cams
• Speakers
• Large monitors/television screens

Software needed:
• Webcam and microphone software drivers
• CODEC: coder–decoder or compression-decompression  echo cancellation software.
Advantages of Video conferencing:
1. Conferences can be called at short notice.
2. Cost is reduced:
• Reduced travelling costs
• No need to pay for hotel accommodation
3. Don’t have to carry documents to conference.
4. Employees will not travel to unsafe places around the world.

Disadvantages of Video conferencing:

1. Delays when talking.
2. People like personal contact.
3. Time differences between countries is an issue,
4. Training people to use the system correctly can be costly and time consuming.
5. Can be very expensive to set up.
Audio conferencing:
Audio conferencing refers to meetings held between people using audio equipment. The equipment
used can be the telephone , a computer, (with built-in microphones and speakers) or an internet
phone.
Phone conference is audio conferencing done over the telephone network.

Voice over Internet protocol (VOIP) is a method used to talk to people using the Internet. One of
the big advantages is that it is either free or at a local rate to anywhere in the world. The main
problems are usually sound quality (echo and ‘weird sounds’ are both common faults). The security
issues over VOIP are:
• identity theft
• viruses and malware (malicious software)
• spamming (sending junk mail)
• phishing attacks (the act of sending an email to a user falsely claiming to be an established
legitimate enterprise in an attempt to scam the user into surrendering private information
that will be used for identity theft).
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Web conferencing:
Web conferencing (webinar) uses the internet to permit conferencing to take place. Multiple
computers are connected to the internet. As with video conferencing it is carried out in real time
and allows the following type of meetings to take place:
• business meetings to discuss new ideas
• presentation
• online education or training

Web conferencing links into video conferencing and audio conferencing through the use of
webcams and built in microphones and speakers.

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A systems analysis team is brought in to review an existing system and suggest a number of
improvements.

System Development Life Cycle:

SDLC is a systematic series of action by which system analysts approach their goal to install a new
or revised system. The steps involved in systems analysis are:
• Analysis
• Design
• Development and testing
• Implementation
• Documentation
• Evaluation

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5.1 Analysis:
The analysis stage involves examining the existing system in detail. The basic steps can be
summarised as follows:
1. Research or collect data from the current system
2. Describe of the current system – establishing the inputs, outputs and

Feasibility study
processing being done
3. Identify of the problem with the current system
4. Agree the objectives with the clients
5. Identify and agree customer requirements
6. Interpret customer requirements
7. Produce a cost-benefit analysis
8. Identify suitable hardware and software
9. Produce a data flow diagram

Collection of Information / Fact finding / Information gathering: is concerned with researching

about the existing system. We need to find how things are done at the moment before we can
suggest an improvement. The four common methods used in fact finding are:

1. Observation: to watch the daily work of the personnel.

Advantages:
i. No planning is necessary and it doesn’t involve working with other
people.
ii. It is possible to see exactly what is done. iii. It is a relatively
inexpensive method.
Disadvantages:
i. People are uncomfortable being watched and may work in a different way.
ii. If workers perform tasks that violate standard procedures, they may not do this while being
watched.

2. Interview: Involves a one-to-one question-and-answer session between the analyst and the
employee/customer.
Advantage: The questions do not have to be fixed in advance; the analyst can change them
according to the answers the interviewees give.
Disadvantages:
i. Interviewing takes a lot of time.
ii. It is relatively expensive, due to the use of the analyst’s time. iii. The
interviewee cannot remain anonymous.
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3. Workers and/or customers filling questionnaires to gather facts in a fast way.
Advantages:
i. These are much less time-consuming than interviews.
ii. Individuals can remain anonymous if they want. iii. It is relatively
inexpensive method.
Disadvantages:
i. Often the number of returned questionnaires is low.
ii. Analyst can’t change questions halfway through.
iii. There is no immediate way to clarify a vague or incomplete answer to a question.

4. Looking at existing paperwork: All documents that are used within a system need to be
examined. The documents may be, for example, bills, invoices, letters, order forms, payslips,
etc. The analyst will be looking for answers to questions such as: How is the data collected?
What data is collected? What happens to this data after it has been collected?
Advantages:
i. The analyst can see for themselves how the paper system operates.
ii. A lot can be discovered about an organisation by examining the documents that it uses.
Disadvantages:
i. It can be very time consuming.
ii. Because of the analyst's time, it is a relatively expensive method.
iii. The documentation is often difficult to understand, so it may be necessary to ask someone to
explain it. This means that we are back to the interview again.

5.2 Design:
Having analysed the existing system, the next stage is to design the key parts of the recommended
system. A list of tasks is summarized here:  Design the data capture forms / input forms
• Design screen layouts
• Design the outputs in the form of screen displays and printed reports
• Producing system flowcharts and/or pseudo code
• Select/design validation rules that need to be used
• Design the file structures and tables (field names, field types, field lengths, field description,
selection of key field, how the data files will be linked, etc)
• Produce any algorithms or program flowcharts
• designing a testing strategy plan
5.2.1 Data capture forms:
These forms allow the data to be input into the system.

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Paper-based forms need to:

• have a heading to make the purpose of the form clear
• make it clear to the person filing the form where they must place their answers
• make use of text boxes, which will limit the amount of information collected
• make use of character boxes where each box allows one character only
• make use of tick boxes to make choices easier
• make sure there is sufficient space to write answers
• use clear fonts and clear text colours to ensure the form is easy to read.

Computer-based data capture forms have the following features:

• use of text boxes to capture key data clearly
• use of on-screen help when completing the form
• use of drop-down/ combo boxes where there are limited choices
• use of radio buttons and tick boxes, requiring a single click of a mouse to select
• automatic validation of data as it is entered
• control buttons (such as next form, clear entry, save, etc.)
• double entry boxes (with verification rules) to check correctness of key data.
• Buttons to aid navigation

Navigation aids:
• Back/previous record button
• Forward/next record button
• New record button
• Submit/save button
• First record button
• Last record button
• Exit button/return to homepage button
• Move to top of page if long form
• Search facility

5.2.2 Screen displays and printed reports:

Screen outputs should be designed:
• to make sure the size of all the output fields is correct
• so that any instructions/descriptions are clear
• so that the full screen is utilised
• so that colours and fonts make the output clear.
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5.2.3 System flowcharts:

System flowcharts are used to show how data flows through a system and also how decisions are
made. They make use of special symbols.

5.2.4 Data Verification:

Verification is a way of preventing errors when data is copied from one medium to another. There
are two common ways:

(a) Visual check:

This is checking for errors by comparing entered data on the screen with the data in the original
document.
(b) Double-data entry:
Data is entered twice, using two people. The computer compares the two entries, either after data
entry or during the data entry process, and identifies any differences.

5.2.5 Data Validation:

It is the process of checking, by the computer, of data at the input stage to detect any data that is
incomplete or unreasonable. For example,

(a) Range Check:

Checks whether data is within given/acceptable values.
Example: A person's age should be in the range>0 but <150.

(b) Limit check:

Similar to range check except that only one of the boundaries is checked.

(c) Length Check:

Checks if the input data contains the required number of characters.
Example: If a field needs six digits then inputting a five- or seven-digit number, should cause an
error message,

(d) Character/type Check:

Checks that the input data does not contain invalid characters.
Example: A person's name should not contain any numbers.

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(e) Format / Picture Check:
Each position within a data item is tested against the item’s pattern to ensure that only valid values
are present.
Example: Date should be in the form dd/mm/yyyy.

(f) Presence Check: checks that the data has been entered.

(g) Consistency Check: checks to see that fields match each other.
Example:
If 'Mr' has been typed into a field called title then the gender field must contain either 'M' or 'Male'

(h) Lookup list Check:

The computer-based system can check the input data against known values by looking up a record
in the files to ensure that the input is valid.

(i) Check Digit:

It is an extra digit appended to a code number. The digit is generated from the code number itself
by applying an algorithm to it.
Check digits can identify three types of error:
• if two digits have been inverted during input, e.g. 13597 typed in instead 13579.
• an incorrect digit entered twice, e.g. 13559 typed in instead of 13579.
• a digit missed out altogether, e.g. 1359 typed in instead of 13579.

5.2.6 File structures:

The fields used in the files need to take the following into account:
• field length
• field name (suitable names should be chosen)  data type.
A data dictionary is used to show suitable field names. An example of a data dictionary:
Field name Field length Field type Suitable
validation
check
product_code 8 Alphanumeric length check
manufacturer_year 4 Numeric range check
product_name 20 Alphanumeric None
colour 2 Alphanumeric look-up check

5.2.7 Design and testing strategy/plan:

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It is necessary to produce a testing strategy or plan to ensure all the possible scenarios have been
tested.

5.3 Development and Testing:

Once the design stage is completed, it is then necessary to create the system and fully test it.

5.3.1 Development:
After the data structures have been designed, they will need to be created using the software or
programming language recommended by the systems analyst. The programmer will produce the
program code needed to solve the problem.

5.3.3Testing strategies:
After testing each module the whole system is tested. Even though each individual module may
work satisfactory, when they are all put together there may be data clashes, etc.
A system is tested by using both test data and live data.

Test data: Types of test data:

• Normal data is data that is acceptable or valid to the system.
• Extreme data are the values at either end of the acceptable range.
• Abnormal data is data which is not acceptable or valid.
• Live data: This is data that has been used in the existing system. It will be used because
the outputs are already known.

As a result of testing, data/file structures, validation routines, input methods, output formats may
need to be amended/improved.

5.4 Implementation:
After the system is fully tested, the systems analyst will want to get the system up and running. His
next steps will be
• to train staff on the new system,
• transfer paper files or electronic files to the new system and  choose a
method of changeover to the new system.

Methods of changeover:
1. Direct changeover:

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New system replaces the existing system immediately. This method can only be used when the new
system has been thoroughly tested. Once the old system is closed down it cannot be reintroduced.
Advantages:
i. The benefits are immediate.
ii. Costs are reduced – since only one system is used there is no need to pay for two sets of
staff. iii. There is less likelihood of malfunction since the new system will have been fully tested.

Disadvantages:
i. If there are problems, there is no backup system.
ii. It can be difficult to make improvements to the new system and keep it working.

2. Parallel running:
The old and new systems are run side by side for a time before the new system takes over
altogether. Advantages:
i. If the new system fails, the old system is still available as a backup.
ii. Staff can be trained to use the new system gradually.

Disadvantages:
i. Two sets of workers have to be paid to keep both system running. ii.
It takes a lot longer to fully implement than direct changeover.

3. Pilot running:
Pilot running is the method adopted by large organisations. The new system is implemented in one
branch of the organisation whilst the other branches continue with their existing system. Workers
from other branches can be taught on the new system before it is introduced to their branch.

Advantages:
i. If the system does not work properly, not all branches are affected.
ii. The later branches benefit by learning from the mistakes made in earlier branches. iii.
The costs are less than parallel running.

Disadvantages:
i. It is a slow method of implementation compared with direct changeover.
ii. It is more expensive than direct changeover, since each pilot scheme needs to be evaluated before
the next stage is introduced.

4. Phased implementation:
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Phased Implementation involves the introduction of the new system one part at a time. When the
system is working perfectly another aspect can be moved onto the new system until all aspects have
been transferred to the new system.
Advantages:
i. If the latest part fails, it is only necessary to go back in the system to the point of failure. ii.
Workers have time to get used to the new system.
iii. Don’t have to pay two sets of staff.

Disadvantages:
i. It is a slow method of implementation compared with direct changeover.
ii. If the new system doesn’t work properly, it is not possible to fall back on the old system.
iii. It is more expensive than direct changeover, since it is necessary to evaluate each phase before
moving to the next stage.

5.5 Documentation:
5.5.1 User Documentation:
It is provided to help users operate the new system. It is written in non technical terms. It includes:
• Purpose of the system
• Limitations of the system
• Hardware and software requirements
• Input and output formats
• How to save files, do a search, sort data, etc
• Sample runs
• Error messages
• Trouble-shooting guide
• Frequently Asked Questions
• Tutorials

5.5.2 Technical Documentation:

It is designed to help programmers and analysts who need to make improvements to the system or
repair/maintain the system. It will include:
• Purpose of the system
• Limitations of the system
• Program listing/coding
• Programming language used
• Program flowcharts
• System flowcharts

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• Hardware and software requirements
• File structures
• Known bugs in the system
• Sample runs (with test data and results)
• List of variables
• Validation routines

5.6 Evaluation:
After the system has been developed, tested and implemented, it must be evaluated. There are a
number of stages in the evaluation process.
A system is usually evaluated against a set of criteria:
• Is the system reliable?
• Does the system do what it was intended to do?
• Is the system easy to use?
• Is the new system efficient?
• Is the solution appropriate?

Evaluation of a new system is done by:

• Comparing the solution with the original task requirements;
• Identifying any limitations to the system;
• Identifying any necessary improvements;
• Obtaining feedback from users;
• Using test results;
• Comparing the performance of the new system with performance of the old.
Some results from the evaluation may require changes to either hardware or software.
Hardware may need to be updated because:
• of feedback from end users
• new hardware comes on the market, making change necessary
• there are changes within the company which require new devices to be added or updated.

Software may need to be updated because:

• of feedback from end users
• changes to the company structure or how the company works may need modifications to the
software
• changes in legislation may need modifications to the software.

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The four main areas where ICT has had an effect on employment include:

• Manufacturing – robots have replaced human workers

• Shop work – online shopping has reduced the need for high street shops

• Banking – the introduction of ATMs and online banking has led to the closure of many
branches
• Office work – spreadsheets, word processors and databases have taken over many of the
tasks carried out by office staff.

6.1 The effects of ICT on employment:

6.1.1 Negative effects – job losses:
The introduction of ICT systems – whether to improve efficiency, reduce costs or improve safety –
has led to redundancies in many areas of industry and commerce.
Office work:
By introducing computer system and new software, the work could be done by fewer staff and in a
much shorter time scale. This could lead to many redundancies and the need for the remaining staff
to retrain.

Manufacturing:
Car manufacturing makes use of robotics. Robots are capable of carrying out the following tasks:
• spraying the bodies with paint
• assembling all the body parts
• assembly of the engine and transmission  fitting the windscreens.

Fitting seats, dashboards and interior trim are usually carried out by a skilled worker.

Factory workers have had to retrain to gain the following new skills:
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• maintenance of the robots
• quality control
• design and development
• marketing
• training other workers.

Advantages of robots over humans:

• Higher productivity.
• More consistent results.
• They work non-stop without breaks.
• They don’t get bored by repetitive tasks.
• They don’t go on strike.

Disadvantages of robots over humans:

• Robots are expensive to purchase and set up in the first place.
• They often need to be reprogrammed for every new task they have to carry out, which can be
expensive and time-consuming.
• If an error occurs in the robot’s programming, or it develops a mechanical problem, a number of
production errors will occur until the fault has been identified.

6.1.2 Positive effects:

Offices have become more pleasant and safer places to work (no noisy typewriters or the dangers of
heavy, overfilled filing cabinets), while the introduction of robots in manufacturing has led to a
cleaner, safer and quitter working environment.

There has been a large increase in job opportunities in some areas, for example:
• network managers and computer technicians
• website designers
• programmers to write operating systems, application software and computer games.
• computer engineers (who build and maintain computer systems)  delivery drivers to deliver
goods to customers.

6.2 The effects of ICT on working patterns:

The introduction of ICT into the workplace has led to a number of changes in working patterns for
staff.
Part-time working:
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Staff work between 1 and 30 hours a week (for example); or someone who works fewer hours per
week than full-time staff – this can be either fewer hours per day or fewer days per week.

Flexible working (flexi-time):

Flexi-time is the ability to choose the start and finish times, but they must complete a full day’s
work.

Job sharing:
With job sharing, a full time job is divided between two part-time workers. Both workers are doing
the same job; one picks up the work where the other left off.

Compressed hours:
In compressed hours, an employee works their full hours for the week but works fewer days.

Different work patterns leads to more contented staff because:

• They can work hours that suit their lifestyle or home circumstances.
• It can allow them to avoid rush –hour commuting in the morning and evening.

Employers see advantages in these work patterns because:

• a contented workforce is more likely to stay in the job thus reducing training cost for new staff.
• flexi-time allows them to remain open for longer hours
• job sharing ensures the company has more than one person with a particular skill set
• compresses hours often lead staff to be more focused in their work
• varied work patterns give more flexibility during busy times and during staff sickness.

6.3 Microprocessor-controlled devices in the home:

The devices fall into two main categories: Labour-saving
devices
• automatic washing machines
• microwave ovens
• cookers
• automatic dishwashers
• robotic vacuum cleaners
• bread-making machines
• smart fridges and freezers

Other types of devices

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• alarm clocks
• television sets
• central heating and air conditioning systems  home entertainment systems.

Advantages of microprocessor-controlled labour-saving devices:

• People no longer have to do manual tasks at home.
• There is no longer a need to stay home while food is cooking or clothes are being washed.
• They give people more time for leisure activities, hobbies, shopping and socialising.
• It is possible to control ovens and central heating systems using smart phones while the owner is
out.
• Automated burglar alarms give people a sense of security as they give a very sophisticated level
of intruder warning at all times.
• Smart fridges and freezers can lead to more healthy lifestyles (they can automatically order
fresh food from supermarkets using their internet connection) as well as prevent food waste.

Disadvantages of microprocessor-controlled labour-saving devices:

• Labour-saving devices can lead to unhealthy lifestyles.
• They tend to make people lazy since there is dependence on the devices.
• People can become less fit if they just lie around at home while the devices carry out many
tasks.
• People may lose their household skills.

Advantages of other microprocessor-controlled devices:

• Microprocessor-controlled devices save energy since they can switch themselves off after
inactivity for a certain time period.
• It is easy to program these devices to do tasks.

Disadvantages of other microprocessor-controlled devices:

• The devices lead to a more wasteful society as once a circuit board fails the device is just
thrown away.
• Some people can find them complex to operate.
• Leaving devices on stand-by is very wasteful of electricity.

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7.1 Physical security:
7.1.1 Health aspects:

Health risk Solution

Back and neck problems/ strain • use fully adjustable chairs to give the correct
posture
• use foot rests to reduce posture pain
• use screen that can be tilted to ensure the
neck is at the correct angle

• take regular breaks

Repetitive Strain Injury (RSI) - damage to • use a wrist rest when using a mouse or
fingers and wrists
keyboard
• use ergonomic keyboards
• use voice-activated software instead of mouse
and keyboard
• take regular breaks

Eyestrain (caused by staring at a computer • use an anti-glare screen or use window blinds
screen too long or bad lighting in the room) • have eyes tested regularly
• take regular breaks
• ensure that there is no screen flicker

Headaches • use an anti-glare screen or use window blinds

• have eyes tested regularly
• take regular breaks

Ozone irritation (dry skin, respiratory problems, • ensure proper ventilation

etc.) - this is caused by laser printers in an office • house laser printers in a designated printer
room
• change to inkjet printers

7.1.2 Safety aspects:

Electrocution:
• use an RCB (residual current breaker)
• check insulation on wires regularly
• don’t allow drinks near computers
• check equipment on a regular basis

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Fire risk:
• ensure good ventilation in the room
• have a fully tested Co2/dry fine fire extinguisher nearby
• fire exits must be kept clear at all times and not blocked by equipment
• electrical sockets should not be overloaded
• reduce voltage requirements - LCD screens instead of CRT monitors
• cables are not to be coiled – the heat generated may be sufficient to start a fire

Tripping wires (trip hazard):

• avoid trailing cables by creating ducts and/or covering cables with carpets
• tuck wires behind furniture to keep them out of the way
• use wireless connections when possible

Heavy equipment falling and causing injury:

• use strong desks and tables to support heavy hardware
• use large desks and tables so that hardware isn’t too close to the edge where it can fall off

7.2 E-safety:
E-safety refers to safety when using the internet, i.e. keeping personal data safe and applies to any
of the following devices:
• mobile phones
• computer or tablet
• game console
• wireless technology

Examples of personal data include:

• name
• address
• date of birth  medical history
• banking details.

Some personal data is often to as sensitive personal data and includes:

• ethnic origin
• political views
• religion
• sexual orientation  criminal activity.

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Some e-safety issues:

• don’t give out any personal information to people who are unknown to you especially online.
• don’t sent people photos of yourself – either online or via a mobile phone - unless a person is
known to you.
• always maintain your privacy settings on whatever device is being used online or during
communications.
• when accessing the internet make sure the websites being visited can be trusted by looking for
https or the padlock sign. When using search engines, always make sure the device settings are
set to ‘safe search’.
• only use websites recommended by teachers and only use a learner-friendly search engine.
• only open emails from known sources.
• only email people you know.
• it is extremely important to be vigilant when using social networking sites, instant messaging or
chat rooms:
o block or report anybody who acts suspiciously or who uses inappropriate language
o be very careful with the language used in chat rooms o always use nickname and
never use real name o keep private and personal data secret o don’t enter private chat
rooms – stay public o never arrange to meet anyone for the first time on your own o
always tell an adult first and meet in a public place o avoid misuse of images o
always use appropriate language o always respect people’s confidentiality

It is also important to be careful when using online gaming since it carries its own risks. Some of
the known risks reported over years include:
• violence in the game itself, which can lead to violent behaviour in reality
• predators
• cyber bullying
• use of webcams
• voice-masking technology
• viruses, phishing or spyware are examples of problems associated with certain online gaming.

7.3 Security of data:

7.3.1 Hacking
Hacking is the act of gaining unauthorised access to a computer system.
Effects of hacking:
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• identity theft or misuse of personal information
• data can be deleted, changed or corrupted on a user’s computer To protect against hacking:
• use of firewalls
• use of strong passwords and user IDs
• use of intrusion detection software
• use of user IDs and passwords

Encryption makes files unreadable if accessed illegally but it does not prevent hacking.

7.3.2 Phishing
The creator sends out legitimate-looking emails to target users. As soon as the recipient clicks on a
link in the email or attachment, they are sent to a fake website or they are fooled into giving
personal data in replying to the email. The email often appears to come from a trusted source, such
as a bank.

Effects of phishing:
• The creator of the email can gain personal data, such as bank account data or credit card
numbers, from the user.
• This can lead to fraud or identity theft.

To protect against phishing:

• Many ISPs or web browsers filter out phishing emails.
• Users should always be cautious when opening emails or attachments.
• Don’t click on executable attachments that end in .exe

Smishing uses the SMS system of mobile phones to send out fake text messages.

Vishing uses a voice mail message to trick the user into calling the telephone number contained in
the message.

7.3.3 Pharming
This is malicious code installed on a user’s computer or on a web server. The code will redirect the
user to a fake website without their knowledge.
Effects of pharming:
• The creator of the malicious code can gain personal data, such as bank account data or credit
card numbers, from users when they visit the fake website.
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• Pharming can lead to fraud or identity theft.

To protect against phishing:

• Some anti-spyware software can identify and remove pharming code from a user’s computer.
• The user should always be alert and look out for clues that they are being redirected to another
website.

7.3.4 Spyware and key-logging software

Spyware is a software that gathers user information through the network connections without the
user being aware that this is happening.
To protect against spyware:
• Use anti-spyware software to reduce the risk.
• The user should always be alert and look out for clues that their keyboard activity is being
monitored.
• Enter passwords by selecting characters from a drop-down menu using a pointing device

7.3.5 Spam
Spam, often referred to as junk email, is usually sent out to a recipient who is on a mailing list or
mailing group. While spam is rarely a security risk, it can lead to denial of services. Denial of
services is an attack on a network that is designed to slow the network down by flooding it with
useless traffic. Spam can be linked to phishing attacks or even the spread of computer viruses.

Spam prevention techniques:

• When using the ‘junk email filter’ set the protection level to high or to safe lists only.  Block
images in HTML messages.
• Look out for check boxes that are already selected when items are bought online; companies
sometimes add a check box to indicate that you have agreed to sell or give your email address to
third party users.
• Do not sign up to commercial mailing lists.
• Unsubscribe from a mailing list that you did not sign up to.
While some regard spam as a cheap way of advertising to many people at the same time, the main
disadvantages are:
• It uses people time
• It generally annoys people
• It uses up valuable bandwidth on the internet, slowing it down
• It can have viruses attached or even be part of a phishing scam
• It can clog up users’ inboxes
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Spam can also affect mobile phones through text messaging and sometimes referred to as ‘spasms’.

7.3.6 Moderated and unmoderated forums

A moderated forum refers to an online discussion forum in which all the posts are checked by an
administrator before they are allowed to be posted.
The internet is essentially an unmoderated forum. No one owns the internet, and it is essentially not
policed. However, most social forums or networking groups on the internet have a set of rules or
protocols that members are requested to follow or they will be deleted.

7.3.7 Cookies
Cookies are small amounts of text that are sent and received through the web browser as we search
or visit internet sites. Cookies track the pages you have visited and save these on your computer
with information about you.
Cookies can be useful if you visit a website frequently and do not wish to enter your login details
each time, but they allow websites you have not visited to know which webpages you have viewed.

7.4 Additional security of data online:

7.4.1 Firewalls
A firewall can be either software or hardware (gateway). It sits between user’s computer and an
external network and filters information coming in and out of the user’s computer. Users on
standalone computers can choose to disable the firewall, leaving their computer open to harmful
traffic from the internet.

Tasks carried out by a firewall:

• examines the traffic between a user’s computer and a public network
• checks whether incoming or outgoing data meets certain criteria
• prevents access to certain undesirable websites; the firewall can keep a list of all undesirable IP
addresses.

• helps prevent viruses or hackers gaining access to the user’s computer or network by blocking IP
addresses but hackers can still have access if they are using an allowed computer
• the user is warned if some software on their system is trying to access an external data source

7.4.2 Security protocol

Secure Socket Layer (SSL) is a type of protocol that allows data to be sent and received securely
over the internet.
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When a user logs on to a website, SSL encrypts the data. A user will know if SSL is being applied
when they see https or the small padlock in the status bar.

7.4.3 Encryption
Encryption is the name given to the converting of data (plain text) into a code (cypher script) by
scrambling it. Even if a hacker gains access to the data he will not be able to understand it. The key
used to encrypt (or encode) the message is known as the encryption key; the key used to decrypt (or
decipher) the message is known as the decryption key.

7.4.4 Authentication
Authentication is used to verify that data comes from a secure and trusted source. It works with
encryption to strengthen internet security. Digital certificates
A digital certificate is a pair of files stored on a user’s computer. Each pair of files is divided into:
• a public key
• a private key

When sending an email, the message is more secure by attaching a digital certificate made up of six
parts:
• the sender’s email address
• the name of the digital certificate owner
• a serial number
• expiry date
• public key
• digital signature of certificate authority (CA)
Operating systems and web browsers maintain lists of trusted CAs.

Passwords
Biometrics
Online credit fraud
Online credit card fraud happens for the following reasons:
• hackers gaining access to a user’s computer through the use of spyware, phishing or pharming.
• the breaking of passwords
• sometimes the URL is altered very slightly in the email and the user ends up visiting a fake
website so it is better to type in the URL.
• it is relatively easy to tap in to wireless networks without password protection
• Wi-Fi hotspots in public places are not secure
• cloud and some retail companies are targets for hackers
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Cloud security
Several computer manufacturers encourage customers to store or backup their files on a medium
known as the cloud. Users purchase cloud storage and can then access all their files from any
device anywhere in the world.
Advantages:
• no need to carry memory sticks
• no need to pay for large storage capacity on your computer
• cloud companies ensure that your files are backed up
• the ability to synchronise (sync) files ensures they are automatically updated across all devices
 allows several users to edit and collaborate on a single file

Data security:
Companies that transfer vast amount of confidential data from their own systems to a cloud service
provider are relinquishing control of their own data security.

Data loss:
There is a risk that important and irreplaceable data could be lost from cloud storage facilities.

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