Course: Computing
Science
Information System Design
and Development Units
Level: National 4/5
April 2013
This advice and guidance has been produced for teachers and other staff who
provide learning, teaching and support as learners work towards qualifications.
These materials have been designed to assist teachers and others with the
delivery of programmes of learning within the new qualifications framework.
These support materials, which are neither prescriptive nor exhaustive,
provide suggestions on approaches to teaching and learning which will
promote development of the necessary knowledge, understanding and skills.
Staff are encouraged to draw on these materials, and existing materials, to
develop their own programmes of learning which are appropriate to the needs
of learners within their own context.
Staff should also refer to the course and unit specifications and support notes
which have been issued by the Scottish Qualifications Authority.
http://www.sqa.org.uk
Acknowledgements
© Crown copyright 2013. You may re-use this information (excluding logos) free of
charge in any format or medium, under the terms of the Open Government Licence.
To view this licence, visit http://www.nationalarchives.gov.uk/doc/open-governmentlicence/ or e-mail: psi@nationalarchives.gsi.gov.uk.
Where we have identified any third party copyright information you will need to obtain
permission from the copyright holders concerned.
Any enquiries regarding this document/publication should be sent to us at
enquiries@educationscotland.gov.uk.
This document is also available from our website at www.educationscotland.gov.uk.
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SOFTWARE DESIGN AND DEVELOPMENT UNITS (COMPUTING SCIENCE NAT 4/5)
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Contents
Introduction ................................................................................................... 4
Approaches to learning, teaching and assessment ................................... 8
Subject content ........................................................................................... 13
Staff notes ................................................................................................ 16
What is a database? ................................................................................. 19
What are webpages?................................................................................ 25
Media types .............................................................................................. 30
Macros, scripting languages and HTML.................................................... 35
Design and testing .................................................................................... 38
Hardware and software requirements ....................................................... 41
Computer architecture .............................................................................. 45
Types of computer .................................................................................... 47
Operating systems.................................................................................... 50
Backing storage devices ........................................................................... 51
Networking/connectivity ............................................................................ 54
Security risks ............................................................................................ 57
Computers and the law............................................................................. 60
Computers and the environment............................................................... 63
Glossary ................................................................................................... 65
Qualifications ............................................................................................ 71
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INTRODUCTION
Introduction
This resource provides advice and guidance for staff delivering Information
System Design and Development units at National 4 and 5.
Before embarking on these units, staff should be familiar with the contents of
the technologies principles and practice paper:
http://www.educationscotland.gov.uk/learningteachingandassessment/curricul
umareas/technologies/index.asp
Staff should also read the computing science professional focus paper
produced by Education Scotland to ensure that they have familiarised
themselves with the key areas of significant change and potential approaches
to teaching and learning.
http://www.educationscotland.gov.uk/nationalqualifications/professionalfocusp
apers/index.asp?bFilter=1&bSortCD=0&11_subjecttopics=New National
Qualifications\|Technologies\|Computing Science (NQ subject)
The general unit information that follows has been taken, summarised and
adapted from the Computing Science National 4 and 5 course support notes.
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INTRODUCTION
Guidance for staff
Key skills, knowledge and understanding
A broad overview of the subject skills, knowledge and understanding that will
be assessed in the Information System Design and Development unit is given
below.
Mandatory skills and knowledge
Applying, with guidance, aspects of
computational thinking across a range of
straightforward contexts.
National 4

Applying aspects of computational thinking
across a range of contexts.
Designing, implementing and testing, with
guidance, digital solutions (including
computer programs) to straightforward
problems across a range of contemporary
contexts.


Designing, implementing and testing, digital
solutions (including computer programs) to
problems across a range of contemporary
contexts.
Communicating basic understanding of key
concepts related to information system
design and development clearly and
concisely using appropriate terminology.
National 5


Communicating understanding of key
concepts related to information system
design and development clearly and
concisely using appropriate terminology.

Communicating understanding of key
concepts related to software design and
development clearly and concisely using
appropriate terminology.

Basic knowledge of the impact of
contemporary technologies on the
environment and society.

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INTRODUCTION
Understanding of the legal implications and
environmental impact of contemporary
information system technologies.

Applying computing science concepts and
techniques to create solutions across a
range of contexts.

Links to prior learning
Entry to this unit is at the discretion of the centre. However, learners would
normally be expected to have attained some relevant skills and knowledge
through prior experience.
Skills and knowledge developed through any of the following, while not
mandatory, are likely to be helpful as a basis for further learning for this
course.
Other SQA qualifications
For National 4:
 Computing Science National 3 or relevant component units
 Numeracy National 3.
For National 5:
 Computing Science National 4 or relevant component units
 Numeracy National 4.
Experiences and outcomes
In this course, any of the following Experiences and Outcomes may be
relevant.
Having investigated a current trend of technological advance in Scotland or
beyond, I can debate the short- and long-term possibilities of the technological
development becoming a reality.
(TCH 4-01a)
I can debate the possible future impact of new and emerging technologies on
economic prosperity and the environment.
(TCH 4-01c)
By discussing the business, environmental, ethical and social implications of
computer technology, I can begin to gain an understanding of the need for
sustainability and accessibility.
(TCH 4-05a)
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INTRODUCTION
I can compare different forms of security software to gain knowledge and
understanding of their functions in protecting contemporary technologies.
(TCH 4-08b)
I can integrate different media to create a digital solution which allows
interaction and collaboration with others.
(TCH 4-08c)
Through research, I can gain knowledge of computer systems or emerging
technologies to understand their differing features and consider their suitability
for the world of work.
(TCH 4-08d)
By learning the basic principles of a programming language or control
technology, I can design a solution to a scenario, implement it and evaluate its
success.
(TCH 4-09a)
I can create graphics and animations using appropriate software which utilise
my skills and knowledge of the application.
(TCH 4-09b)
I can use features of software to create my own animation which can then be
used to create an animated sequence.
(TCH 4-09c)
Progression from this unit
From National 4 progression may be possible to:




Computing Science National 5
National Certificate Group Awards in computing, IT and related disciplines
other technological courses at National 4
employment, apprenticeships and/or training in IT and related fields.
From National 5 progression may be possible to:




Higher Computing Science
National Certificate Group Awards in computing, IT and related disciplines
other technological courses at National 5
employment, apprenticeships and/or training in IT and related fields.
Ultimately, for some, progression may be possible to:




Advanced Higher Computing Science
a range of computing-related Higher National Diplomas (HNDs)
degrees in computing, IT and related disciplines
careers in computing, IT and related disciplines.
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APPROACHES TO LEARNING, TEACHING AND ASSESSMENT
Approaches to learning, teaching and assessment
Computing science, like all new and revised national courses, has been
developed to reflect Curriculum for Excellence values, purposes and
principles.
The approach to learning and teaching developed by individual centres should
reflect these principles. Learners should be encouraged to participate fully in
active learning and practical activities by working together, talking, listening,
reading or reflecting on a topic while staff act as a facilitator.
An appropriate balance of teaching methodologies should be used in the
delivery of the course and a variety of active learning approaches is
encouraged, including the following.
Activity-based learning
Whole-class, direct teaching opportunities should be balanced by activitybased learning and practical tasks. An investigatory approach is encouraged,
with learners actively involved in developing their skills, knowledge and
understanding by investigating a range of real-life and relevant problems and
solutions related to areas of study. Learning should be supported by
appropriate practical activities, so that skills are developed simultaneously with
knowledge and understanding.
Group work
Practical activities and investigations lend themselves to group work, and this
should be encouraged. Working within a group will encourage learners to
collaborate and work co-operatively with others. Learners engaged in groupwork strategies capitalise on one another’s knowledge, resources and skills in
questioning, investigating, evaluating and presenting ideas to one another.
While working as a team is not specifically identified as one of the skills for life,
learning and work for this course, and therefore is not assessed, it is a
fundamental aspect of working in the IT and related industries and so should
be encouraged and developed by staff.
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APPROACHES TO LEARNING, TEACHING AND ASSESSMENT
Problem-based learning
Problem-based learning (PBL) is another strategy that will support a learner’s
progress through this course. This method may be best utilised at the end of
an outcome or a topic where additional challenge is required to ensure
learners are secure in their knowledge and understanding, and to develop the
ability to apply knowledge and skills in less familiar contexts. Learning through
PBL develops a learner’s problem-solving, decision-making, investigative,
creative-thinking, team-working and evaluative skills.
Computational thinking
Computational thinking is recognised as a key skill set for all 21st-century
learners – whether they intend to continue with computing science or not. It
involves a set of problem-solving skills and techniques used by software
developers to write programs.
There are various ways of defining computational thinking. One useful
structure is to group these problem-solving skills and techniques under five
broad headings:
 Abstraction: seeing a problem and its solution at many levels of detail and
generalising the information that is necessary. Abstraction allows us to
represent an idea or a process in general terms (eg variables) so that we
can use it to solve other problems that are similar in nature.
 Algorithms: the ability to develop a step-by-step strategy for solving a
problem. Algorithm design is often based on the decomposition of a
problem and the identification of patterns that help to solve the problem. In
computing science as well as in mathematics, algorithms are often written
abstractly, utilising variables in place of specific numbers.
 Decomposition: breaking down a task so that we can clearly explain a
process to another person – or to a computer. Decomposing a problem
frequently leads to pattern recognition and generalisation/abstraction, and
thus the ability to design an algorithm.
 Pattern recognition: the ability to notice similarities or common differences
that will help us make predictions or lead us to shortcuts. Pattern
recognition is frequently the basis for solving problems and designing
algorithms.
 Generalisation: realising that a solution to one problem may be used to
solve a whole range of related problems.
Underpinning all of these concepts is the idea that computers are
deterministic: they do exactly what you tell them to do. The corollary of this, of
course, is that they can be understood.
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APPROACHES TO LEARNING, TEACHING AND ASSESSMENT
Whilst computational thinking can be a component of many subjects,
computing science is particularly well-placed to deliver it. Staff are encouraged
to emphasise, exemplify and make these aspects of computational thinking
explicit (at an appropriate level) wherever there are opportunities to do so
throughout the teaching and learning of this course and its units.
Using online and outside resources
Throughout the teaching of this course, the stimulation of learners’ interest
and curiosity should be a prime objective. Engagement with outside agencies
or industry professionals can greatly enhance the learning process. Online
resources, such as those listed in the individual unit support notes, may
provide a valuable addition to teaching and learning activities, encouraging
research, collation and storage of information and evaluation of these
materials. The use of interactive multimedia learning resources, online quizzes
and web-based software can also be used to support activity-based
approaches.
Assessment activities, used to support learning, may be usefully blended with
learning activities throughout the course, for example by:





sharing learning intentions/success criteria
using assessment information to set learning targets and next steps
adapting teaching and learning activities based on assessment information
boosting learners’ confidence by providing supportive feedback
encouraging self- and peer-assessment techniques wherever appropriate.
Working towards units and course
Learning and teaching activities should be designed to develop:
 skills and knowledge to the standard required by each unit and to the level
defined by the associated outcomes and assessment standards
 the ability to apply the breadth of knowledge, understanding and skills
required to complete the Added Value Unit at National 4 or the course
assessment at National 5 successfully.
Meeting the needs of all learners
Within any class, each learner will have individual strengths and areas for
improvement.
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APPROACHES TO LEARNING, TEACHING AND ASSESSMENT
For example, within a National 4 class there may be learners capable of
achieving National 5 standards in some aspects of the course. Where
possible, they should be given the opportunity to do so.
Staff need to consider both the outcomes and assessment standards, and the
table of content in Appendix 2 of the SQA unit support notes, to identify the
differences between National 4 and National 5.
In some aspects of the course the difference between National 4 and National
5 is defined in terms of a higher level of skill. For example, in the Information
System Design and Development unit, Outcome 1 requires National 4 learners
to ‘develop simple information systems using appropriate development tools’,
by creating a structure with links, integrating different media types and
identifying and rectifying errors, while at National 5 in the similar Outcome 1
learners are also required to create a user interface and write or edit simple
code.
In other aspects of the course the difference between National 4 and National
5 is defined by additional or more in-depth knowledge. For example, in the
Software Design and Development unit, National 4 learners need to report on
a contemporary software-based application, while National 5 learners need to
compare two different software languages or environments.
When delivering this course to a group of learners, with some learners working
towards National 4 and others towards National 5, it may be useful for staff to
identify activities covering common knowledge and skills for all learners, and
additional activities for National 5 learners. This is particularly appropriate
where the National 5 learners have come directly from the Broad General
Education without previously studying National 4.
Where National 5 learners have studied National 4 in a previous year, it is
important to provide them with new and different contexts for learning to avoid
de-motivation.
Learning about Scotland and Scottish culture will enrich the learners' learning
experience and help them to develop the skills for learning, life and work they
will need to prepare them for taking their place in a diverse, inclusive and
participative Scotland and beyond. Where there are opportunities to
contextualise approaches to learning and teaching to Scottish contexts, staff
should consider this.
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APPROACHES TO LEARNING, TEACHING AND ASSESSMENT
Gathering evidence
Assessment should be an ongoing process that permeates effective learning
and teaching. Staff are encouraged throughout the Curriculum for Excellence
documentation to adopt imaginative and creative approaches to assessment
that take account of learners’ experience in terms of challenge, breadth and
application. Staff should refer to the principles of assessment as laid out in
Building the Curriculum 5:
http://www.educationscotland.gov.uk/thecurriculum/howdoyoubuildyourcurricul
um/curriculumplanning/whatisbuildingyourcurriculum/btc/btc5.asp
For unit assessment purposes, a variety of methods of assessment should be
used to gather a rich range of evidence such as creation of media, written
work, role-play and oral presentations. More detail on gathering evidence can
be found on the SQA secure website in the unit assessment support notes for
National 4 and 5.
Staff should share learning and assessment criteria with learners, provide
effective feedback, encourage peer- and self-assessment, and use effective
questioning techniques.
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SUBJECT CONTENT
Subject content
Below is a table summarising the content for the Information System Design
and Development unit taken from the Computing Science National 4 and 5
course support notes:
Information System Design and Development
Exemplification and implementation of the following in an application development
environment:
Topic
Structures and links
National 4
Database structure: field,
record, file
Field types: text, numbers,
date, time, graphics,
calculated
Website, page, URL
Hyperlink
User interface
Target audience
Structures and links
Database structure: field,
record, file
Field types: text, numbers,
date, time, graphics,
calculated
Website, page, URL
Hyperlink
National 5
Database structure: flat file,
linked tables
Field types: text, numbers,
date, time, graphics,
calculated, link, Boolean
Field lengths and range
Key field
Website, page, URL
Hyperlink: internal, external
Navigation.
User requirements: visual
layout, navigation, selection,
consistency, interactivity,
readability
Database structure: flat file,
linked tables
Field types: text, numbers,
date, time, graphics,
calculated, link, Boolean
Field lengths and range
Key field
Website, page, URL
Hyperlink: internal, external
Navigation
Frames, sequence
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SUBJECT CONTENT
Media types
Coding
Sound, graphics, video, text
Macros
Testing
Purpose, features,
functionality, users
Simple descriptions of main
features and functionality
Technical
implementation
(hardware and
software
requirements)
Hardware:
 input and output devices
 processor clock speed
(Hz)
 memory (RAM, ROM)
Software considerations:
 operating system
platform required
Technical
implementation
(storage)
Storage devices:
 built-in, external, portable
 magnetic, optical
 capacity, speed
 rewritable, read-only
Technical
implementation
(networking/
connectivity)
Stand-alone or networked
LAN/internet
Wired/wireless
14
Standard file formats:
 text: txt, rtf
 audio: wav, mp3
 graphics: jpeg, bmp, gif, png
 video: mpeg, avi
 spreadsheet: xls, csv, xml
 pdf
Factors affecting file size and
quality, including resolution,
colour depth, sampling rate
Need for compression
Scripting languages (including
JavaScript)
Mark-up languages
Links and navigation
Matches user interface design
Description of purpose
Users: expert, novice, age
range
Hardware:
 input and output devices
 processor type and speed
(Hz)
 memory (RAM, ROM)
 device type (including
supercomputer, desktop,
laptop, tablet, smartphone)
Software considerations:
 operating systems
Storage devices:
 built-in, external, portable
 magnetic, optical
 solid state
 capacity, speed
 rewritable, read-only
 interface type and speed
Peer-to-peer versus
client/server
Media: wired, optical, wireless
Comparison of local versus
web/cloud
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SUBJECT CONTENT
Security risks
Viruses, worms, Trojans
Hacking
Security precautions
Anti-virus software
Legal implications
Environmental impact
Spyware, phishing, keylogger
Online fraud, identity theft.
DOS (Denial of Service)
attacks
Passwords/encryption
Biometrics
Security protocols and firewalls
Use of security suites
Computer Misuse Act
Data Protection Act
Copyright, Designs and
Patents Act (plagiarism)
Health and safety regulations
Energy use
Disposal of IT equipment
Carbon footprint
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SUBJECT CONTENT
Staff notes
The main purpose of this text is to provide a single document with the basic
theory for the Information System Design and Development unit. It does not
provide a step-by-step practical guide in a particular application because there
are a variety of excellent resources available already for this purpose and
different departments will approach evidence gathering in different ways. The
unit assessment support notes for Computing Science National 4 and 5
provide examples of the sort of work learners are expected to be doing to
prove that they are working at the correct level. The notes are by no means
exhaustive and there are new documents and guides being shared every day
on the CAS forum (http://community.computingatschool.org.uk/), which is an
excellent community for computing staff to share ideas and resources.
Useful websites
A short and by no means exhaustive list of useful computing websites.
Back issues of Computer & Information Sciences & Engineering newsletters
http://www.nsf.gov/cise/csbytes/pastissues.jsp
Computer Science Unplugged
http://csunplugged.org/activities
The Roles of Variables home page
http://www.cs.joensuu.fi/~saja/var_roles/
Wikibooks on the topic of computing
http://en.wikibooks.org/wiki/Subject:Computing
Peer Instruction for Computer Science
http://www.peerinstruction4cs.org/
A site which allows staff to create free games, quizzes, activities and diagrams
http://www.classtools.net/
BBC site with a collection of excellent video clips to illustrate course theory,
with real-life examples
http://www.bbc.co.uk/learningzone/clips/
Harvard’s main page of resources for the Scratch programming environment
http://cs.harvard.edu/malan/scratch/index.php
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SUBJECT CONTENT
Computer Science for Fun magazine
http://www.cs4fn.org/teachers/activities/
Online interactive tool for learning programming
http://www.codecademy.com/#!/exercises/0
National forum for computing staff to support one another and share
resources, experiences and ideas
http://community.computingatschool.org.uk/
Home page for Education Scotland computing resources and documentation
http://www.educationscotland.gov.uk/nationalqualifications/subjects/computing
.asp
Recommended books
Below are some books that may help learners and staff in aspects of the
Computing Science National 4 and 5 courses.
Beginning Programming For Dummies (paperback), Wallace Wang. ISBN-13:
978-0470088708
Higher Computing (paperback), John Walsh. ISBN-13: 978-0340905630
How to Pass Intermediate 2 Computing (paperback). Frank Frame, ISBN-13:
978-1444108361
How to Pass Standard Grade Computing (paperback), Frank Frame. ISBN-13:
978-0340973912
Information Systems for You: Student's Book (paperback), Stephen Doyle.
ISBN-13: 978-0748763672
Megabyte (paperback), Simon Cotton, Graham Teager and Robert Austin.
ISBN-13: 978-0198328254
Pathways to Excellence: Level 3: Computing and ICT (paperback), Frank
Frame and John Mason. ISBN-13: 978-1444110791
Pathways to Excellence: Level 4: Computing and ICT (paperback), Frank
Frame and John Mason. ISBN-13: 978-1444110807
PCs For Dummies (paperback), Dan Gookin. ISBN-13: 978-0470465424
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SUBJECT CONTENT
Raspberry Pi User Guide (paperback), Eben Upton and Gareth Halfacree.
ISBN-13: 978-1118464465
Scratch Programming for Teens (paperback), Jerry Ford Jr. ISBN-13: 9781598635362
Standard Grade Computing Studies (paperback), John Walsh. ISBN-13: 9780340885000
The BCS Glossary of IT and Computing Terms (paperback), British Computer
Society. ISBN-13: 978-0131479579
The Game Maker's Apprentice (paperback), Jacob Habgood and Mark
Overmars. ISBN-13: 978-1430213475
Visual Basic 6 For Dummies (paperback), Wallace Wang. ISBN-13: 9780764503702
Other resources
There are other digital resources which at time of writing are available for
Intermediate 1/2 Computing and Standard Grade and could provide additional
exercises and theory for the Computing Science National 4 and 5 courses.
These are listed below.
Softplanet Intermediate 2 and Standard Grade
http://www.softplanetgroup.com/study-software/businesscomputing/intermediate-2-computing
http://www.softplanetgroup.com/study-software/business-computing/standardgrade-computing
Webcal Intermediate 1/2 and Standard Grade
http://www.webcal.esmartbiz.com/prod0405.htm
Exercises and content
To reduce the costs of reprographics and allow differentiation in a multi-level
class, National 4 and 5 content is included in the same document. National 5
exercises are in bold and National 5 content is highlighted using shaded
blocks.
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SUBJECT CONTENT
What is a database?
The contacts feature on a mobile phone and the products listed and grouped
on a games, clothes or music website are all databases. A database is simply
a list of items, all of the same kind, organised in a way that makes it easier to
choose or read from the list.
Most databases are stored electronically because this makes them quicker
and easier to edit, search and sort, and they take up less physical space.
Editing a database is when new details are added to the database or existing
details are changed. Searching a database simply involves finding a particular
set of information from the database, for example everyone whose surname is
Smith. Sorting a database is the act of reorganising the database into another
order, for example in ascending alphabetical order by surname from A to Z or
in descending numerical order by age from oldest learner to the youngest
learner.
Databases are used by many groups of people, for example:
 by schools, so that they know which pupils are absent
 by supermarkets, so that they know what items are in stock
 by banks, so that they know how much money their customers have.
A database application (such as MS Access) is required to create an
electronic database. A database application is a program that organises the
data entered into a computer.
The computer user enters into the computer the data that he or she wants to
keep, for example a list of customers or all the people in a club.
The database application arranges the data into a table.
Here is the data table from an example film database.
Film
Certificate
Genre
Goodfritters
18
Gangster
Diary of a Lazy Kid
PG
Kids
The Armwrestler
15
Drama
Inglorious Bar Stewards
18
War
Record
Field
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SUBJECT CONTENT
All the data for one film is called a record (not to be confused with a row in a
spreadsheet). The Armwrestler is suitable for people aged 15 years and over
and is a drama. Each piece of data for a film – the name, the certificate and
the genre – is called a field in the data table.
When planning and designing a database the types of field used must be
considered. There are a number of different field types to choose from:
 text
 numbers
 date
 time
 graphics
 calculated
 link
 Boolean
eg Bob; DD3 O12; £20+VAT
can be integers (whole numbers) or real (floating point), eg
1.34
eg 01/01/2013; 1 January 2013
eg 23:30:00 or 11:30 pm
databases can hold pictures, eg employee photo or the
picture of a product
similar to a spreadsheet, calculated fields carry out a
calculation on another field or fields and displays the result
a hyperlink to a file outside of the database, eg a web page
holds one of two values, eg Yes or No, True or False
Types of database
The two main types of computerised database are flat file and relational.
Flat-file databases
A flat-file database is like an electronic card index file. In this type of database,
the data is stored in a single table. In the case of a games rentals system, the
table would store data about both members and games, as shown in the table
below.
Cost
Date
rented
Date
returned
Fallover 3
£2.50
03/09/12
05/09/12
Date
membership
started
03/09/11
003
GBH 5
£2.50
02/09/12
05/09/12
02/09/11
003
GBH 5
£2.50
10/09/12
14/09/12
10/09/11
£2.50
03/09/12
05/09/12
03/09/11
£2.50
12/09/12
14/09/12
12/09/11
£2.50
15/09/12
17/09/12
15/09/11
Game
code
Game title
001
011
Headband
4
Blacktops 2
011
Blacktops 2
008
20
Member
name
Telephone
number
Billy Whizz
Beryl the
Peril
Desperate
Dan
Dennis the
Menace
Burglar Bill
Bob
Hoskins
123344
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545454
676767
876454
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014
015
Toilet Rim
£2.50
03/09/12
06/09/12
03/09/11
Farmers
Field 3
£2.50
06/09/12
09/09/12
06/09/11
Freddie
Flintoff
Tom
Thumb
667854
454378
The flat-file database above contains one record for each computer game
rental. Flat-file databases have a number of problems:
 Data can be duplicated. Because a new record is created for each game
rented, the member details would have to be copied onto each new record,
which is inefficient.
 Duplicating data increases the chance of human error when typing in the
same customer’s details a number of times. It can then be hard to be sure
which the correct entry is.
 It is not possible to store information about a member without entering
details of a game rental. In other words a customer’s details can only be
recorded once they rent something.
 Removing a game from the database may remove the only record that
stores details of a member.
Relational databases
An improvement on flat-file databases is the use of a relational database. A
relational database stores data in more than one table. The idea is to ensure
that data is only entered and stored once, so removing the possibility of data
duplication and inconsistency. In the above example this would mean that
there would be a separate game table, rental table and customer table.
Primary or key fields
A key is a field or set of fields which uniquely identifies a record. For example
in a customer database or file, there may be a number of clients called John
Smith so to uniquely identify which John Smith it is there could be a key field
called Customer ID.
Foreign key
A foreign key is a field that is not a primary key in its own table, but is a
primary key in another table. Put another way, a foreign key in one table
points to a primary key in another table. In the example above, if the DVD
rental table was broken down into a customer table and rental table then the
primary key in the customer table might be called Customer ID. This Customer
ID field would also appear in the rental table as a foreign key.
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Field length and range
The length of a field refers to how many characters the database designer
sets aside for a particular field to hold. The age field in a customer database
should only need three characters, for example, because people do not live to
be thousands of years old (this would require four or more characters) but they
may live to be older than 99, thus requiring three characters.
The range of a field refers to the acceptable range of values it will accept. An
example of this might be if a field holds the month as a number from 1
(January) to 12 (December) then the range is 1 to 12.
Input validation can be used to make sure that a user only inputs data in the
correct format and if the user makes an error the database will display an error
message and ask the user to re-enter, eg in the above scenario, if the number
13 was entered for a month. Similarly, validation could check that the data
input is not too long, eg a user puts in an age of 12,000, or too short, eg a
telephone number of 1234.
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Exercises
1.
You own 100 computer games and you want to keep information about
them all on computer. You should use a:
(a)
(b)
(c)
(d)
2.
spreadsheet
database
word processing program
drawing program.
Here is part of a database where information about cars is stored.
Name of field
x
Model of car
Number of doors
Type of field
Text
Text
y
Sample data
Ford
Focus
5
The letter x shows the name of a missing field. Study the sample data
and decide on a name for field x:
A
B
C
D
3.
In the database above, the letter y shows the missing type of field for the
number of doors on the car. Choose the correct field type for y:
(a)
(b)
(c)
(d)
4.
Bob
colour of car
car registration
make of car.
text
number
date
graphic.
You keep a database of film stars. When a new star appears in a film
you need to:
(a)
(b)
(c)
(d)
edit a star’s record
add a new field
add a new record
create a new file.
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5.
It is very common to find duplication of data in a flat-file database. This
can lead to data becoming inconsistent. What type of database should
be used to reduce duplication of data and inconsistency?
6.
Using a database package that staff have shown you, create your own
flat-file criminal database. First plan out on paper which fields you will
need and which field types those fields will be. Then create and populate
the database with fictitious criminals.
7.
After staff have demonstrated how to create linked tables, take the flatfile database you designed and created in task 6 and design and create
a relational database with multiple linked tables.
8.
With a partner, research how databases are used in society. Pick a
usage and create a presentation, podcast, poster or leaflet summarising
your findings.
9.
Evaluate another group’s submission for task 8. Give the group two
pieces of positive feedback regarding areas you liked and offer one
suggestion for improvement.
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What are web pages?
A website is a collection of web pages with information about a topic, person,
place or organisation. Users interested in a topic can connect to the internet
and visit a website to read the individual web pages about that topic.
The ‘landing’ page of a website is called the home page. Home pages provide
the user with links to other pages in the website.
The home page has a web address such as www.bbc.co.uk. This web
address is called a URL, short for Uniform Resource Locator.
Web pages can be created in hypertext mark-up language (HTML) and can
contain text, graphics, sound and video. The process of jumping from one
page to another or from one part of a web page to another part of the same
page is achieved by using hyperlinks. Hyperlinks can be internal within the
same page or website, or external, linking to an entirely different website. A
hyperlink could be a piece of text or a picture that is ‘clickable’; generally when
the mouse pointer hovers over a link it changes from an arrow to a hand icon.
Navigation
Navigation is the term used to describe how a user moves from one part of a
web page to another, from web page to web page and website to website.
To view a web page requires software called a web browser. There are many
of these on the market, including Safari, Internet Explorer, Chrome and
Firefox. Browsers include features specially designed to make accessing,
viewing and navigating web pages as straightforward as possible. Some of
these features are listed below:
 Address bar: allows user to type in web address or URL directly.
 Backwards, home and forwards buttons: allow user to flick back and
forward through web pages.
 Scroll bar: allows user to view web pages that are longer than the screen
area.
 Favourites/bookmarks: allow user to save the website in the browser's
memory so that on future occasions the user does not have to remember
and type in the full address again.
 History: the browser keeps a record of past websites that have been
visited, which allows users to back track to websites that they may have
used previously but forgotten to bookmark.
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Sequence
In web page design, sequence refers to how navigation on a website is
structured. There are three main ways to structure pages on a website:
1.
Linear: web pages can only be accessed in order, perhaps by topic or
chronologically.
Page
1
2.
Page
2
Page
3
Page
4
Page
5
Hierarchical: web pages are organised into groups and subgroups, and
users ‘drill’ down through categories or groups to get to specific pages or
subgroups.
Home
page
Games
PC
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DVDs
Books
Console
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3.
Web: web page navigation is designed in such a way as to let users get
to web pages from a number of routes.
Page
2
Page
1
Page
3
Page
4
Page
5
User interface
The interface just means how a piece of software and the user communicate
together, how the software gives the user feedback and how the user inputs
data into the program. Most applications use a graphical user interface with
windows, icons, menus and a pointer as this method is regarded as userfriendly.
Target audience
When creating an information system such as a web page it is important to
consider the target audience. The target audience involves factors like:





age group
expertise in computer use
level of education
geographical location
accessibility.
If the design does not cater for the needs and preferences of the intended
audience then users will choose not to use the information system. A website
or presentation about computer games targeted at teenagers will look very
different from a resource about cake-baking for adults.
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Visual layout
White space gives the reader‘s eyes a rest and separates one type of
information from another. Too little white space makes for a crowded,
unappealing page. Information should be organised so that there is space
between items and the amount of text for the user to read on screen at once is
reduced as much as possible.
Navigation
It can be frustrating for a web page user if they cannot figure out where to go
or where they are on a site. Buttons to get around a site should be easy to find
and clear to read. Any rollover submenu should be designed to give users
time to drill down before they disappear. Users also want to know where in the
site they are. Large sites use something called a breadcrumb trail usually at
the top of the current page to allow a user to backtrack to previously visited
pages further up the navigational tree. In web design there is a three-click rule
which says that important information should be no more than three mouse
clicks away at any time.
Consistency
Consistency means making everything on the page and website match. This
includes the fonts, colours, button styles and spacing. Everything should have
a similar theme to make the design look professional and easy on the eye. If a
designer uses too many different types of font, graphics and button types over
a website, the site will become more difficult to understand for the user and
less appealing.
Readability
This involves making sure the page, including the typeface (font), is easy to
read. This can be achieved by avoiding using all capitals, using large enough
text and keeping text left aligned with a contrasting background colour for that
page against the text colour. An example of this is that web designers don’t
usually use pink coloured text on a red background because the text becomes
hard to read.
Interactivity
An interactive site or information system is one which allows users to provide
information as well as just be passive readers. Interactivity can be achieved
through things like a built-in search engine facility, discussion areas, areas on
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a page which change to reveal more information depending on where the user
puts their mouse on screen etc. In general, interactive websites and
information systems will be more appealing and engaging for a user.
Exercises
1.
Every web page is filled with dozens of these, each sending you to some
related web page or picture/file. What am I?
2.
Name three ways of navigating on a website.
3.
What does URL stand for and what is it?
4.
What are the three ways in which a website can be organised in terms of
how the user moves from page to page?
5.
What is the difference between an external hyperlink and an internal
hyperlink?
6.
When designing a web page what do we mean by target audience?
7.
Name and describe three aspects of good web design.
8.
With the web design program or editor that staff have shown you, create
a simple web page about yourself, what you study, your hobbies and
interests.
9.
Swap over with a neighbour and read their web page. Evaluate the
page, giving your neighbour two pieces of positive feedback regarding
areas you liked and offer one suggestion for improvement.
10.
With a neighbour, research what makes a good website and find
examples of well-designed websites and examples of badly designed
websites. After you have enough information, design and create a group
of linked pages explaining your findings, with links to the example sites
you have found.
11.
Swap with another group and read their submission for question 11. As
a larger group, prepare a report summarising the key points for good
website design. Each person in the group should be ready to feedback
their group's findings to the rest of the class.
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Media types
Multimedia combines different types of media such as text, audio, video and
graphics into one system. By combining two or more types of media together
in, for example, a presentation or website, the end result should be more eyecatching and engaging.
Each media type has a number of different standard file formats. Standard file
formats are file types that can be recognised, opened, worked with and saved
by a number of different computers and applications.
Text
Txt
The txt file format stores information about the characters in a document
without any information about the styles or fonts, just the plain text. Its
simplicity means that it is accepted by virtually all computer systems. Because
txt doesn’t contain any formatting information (apart from paragraph spacing),
it does not take up as much space on a hard disk and will take less time to
transmit across a network, for example in an email.
Rich text format (rtf)
Rich text format files contain more formatting information than txt files,
retaining information about indentation, styles, fonts and sizes.
Compression
Data files can be stored in uncompressed (full-fat version) or compressed (diet
version) formats. Uncompressed files have all of the original data and are
therefore high quality, but also have a large file size. Compressed formats
have a reduced file size but as a result, in general, there can be a loss in
quality. Files are compressed so that they take up less file space, thus
allowing more files to be stored. Another reason for compression is so that
files can be sent over a network quicker than sending an uncompressed file,
eg web pages will load more quickly and emails with attachments will be sent
and received more quickly and use less data bandwidth.
Factors affecting file size
The main factor that affects the size of a file, be it a graphic, sound or video
file, is the quality or resolution that it is saved at. The higher the quality or
resolution a file has, the better the quality but the more data is being saved.
More data means more disk space, longer downloads from the internet and
therefore more of a user’s data allowance being consumed. Taking a digital
photo as an example, there are two factors affecting file size:
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 resolution – how many pixels are used to represent the picture
 colour depth – the size of the colour palette.
Below are two examples of file size calculations for graphics:
1.
A black and white graphic 4 inches by 4 inches and using 300 pixels per
inch.
(4 × 300) × (4 × 300) = 1440000 pixels
For black and white only one bit is required per pixel (0 for blank, 1 for
filled) so 1440000 bits.
1440000/8 = 180000 bytes.
180000/1024 = 175.78 kilobytes.
2.
A true colour (24 bits used per pixel, allowing 16 million colours) graphic
4 inches by 4 inches and using 300 pixels per inch.
(4 × 300) × (4 × 300) = 1440000 pixels
For true colour 24 bits per pixel, therefore 1440000 × 24 = 34560000
bits.
34560000/8 = 4320000 bytes
4320000/1024 = 4218.75 kilobytes
4218.75/1024 = 4.12 megabytes
Sampling/frame rate
For video and sound, the frame or sampling rate has an effect on the quality
and file size. The more snapshots or samples recorded per second the greater
the quality, but the more data that has to be captured and therefore the
greater the file size.
Audio
Wav
Wav files are uncompressed files containing digitised sound data. They are
often used in places such as digital telephone systems and CD players.
MP3
A compressed file format for sound, the MP3 file uses lossy compression to
reduce file size by taking out frequencies of sounds that the human ear cannot
detect, so quality does not suffer.
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Graphics
Bitmap (bmp)
This is an uncompressed file format with data being stored about each pixel
(picture element) in an image.
GIF
A compressed file format using lossless compression. GIFs allow users to set
a transparent colour in the image but only have a colour palette of 28 or 256
colours, so are best suited for cartoons, graphs and drawings rather than
photos.
JPEG
A compressed file format that takes a bitmap and reduces the file size by
cutting out data that the human eye would not notice, like subtle differences in
shading. This file format is ideal for photos.
PNG
The portable network graphics (PNG) file format is an improved version of the
GIF format. It is lossless but has a larger palette of colours and allows opacity
(the user can decide how transparent a colour is).
Video
AVI
Uncompressed file format for storing video.
MPEG
A lossy compression format for video that achieves a smaller file size by only
storing some of the key frames of video.
Spreadsheets
XLS
The default file format for Microsoft’s Excel spreadsheet package, which holds
data in worksheets, charts and macros.
CSV
A comma-separated values (CSV) file stores tabular data (numbers and text)
in plain-text form. Plain text means that the file is a sequence of characters.
CSV is ideal for transferring data between different makes and types of
applications, for example taking a list of names from a database and importing
it into a spreadsheet without having to retype all the names again.
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XML
Extensible mark-up language (XML) is a mark-up language like HTML but
XML was created to structure, store and transport information. HTML is about
displaying information, while XML is about carrying information.
PDF
PDF (portable document format) is a file format for documents devised by a
company called Adobe. To view a PDF requires the user to download and
install Adobe’s free reader software. Many programs, such as Microsoft Word,
allow users to save documents as PDFs instead of their own native format (eg
.doc in MS Word). One of the advantages of saving a file as a PDF is that
anyone with a computer and the free Adobe Reader program can view it,
hence the word portable.
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Exercises
1.
Which of these file types is a sound file?
A
B
C
D
2.
A video file needs to be _______________ to reduce the file size.
A
B
C
D
3.
wav
gif
avi
jpeg
compressed
saved
edited
deleted
A txt file is used to store:
A
B
C
D
video
sound
text
graphic
4.
What type of file is an avi?
5.
Name two factors that affect the file size of a graphic.
6.
Create a piece of media of your own choice, be that a sound file,
graphic, video or animation. Save the file in its native version and note
its file size.
7.
Is there a method of compressing the size of the file you created in
question 6 either in the package you are using or in another package? If
so save the file in a compressed format and make a note of the new file
size. If not explain what steps you took to come to this opinion.
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Macros, scripting languages and HTML
Macros
Small programs called macros can be written within some existing application
packages rather than using a standalone programming environment. For
example, a series of complex or frequently used actions in a spreadsheet or
database package can be recorded and then repeatedly activated in the future
by a single key press or combination. Macros save time by executing a
complex set of frequently used instructions quickly, time and time again. An
inexperienced user can use powerful tools without having to know the detailed
steps behind them. Macros can be created within an application by selecting
the macro function from the menu, giving the macro a name, assigning the
key/keystrokes that will activate it and then recording the instruction/actions.
Another way of creating macros is by using a scripting language.
Scripting language
There are two types:
1.
2.
those built (embedded) into an application
those which work with the operating system and across and between
compatible applications.
An expert user of an application package would use a scripting language to
automate a repetitive task that had to be carried out frequently, thus saving
time.
Examples of scripting languages include VBScript, JavaScript and Perl.
JavaScript is a simple scripting language invented specifically for use in web
browsers to make websites more dynamic. On its own, HTML is capable of
outputting more-or-less static pages. Once you load them up your view doesn't
change much until you click a link to go to a new page. Adding JavaScript to
your code allows you to change how the document looks completely, from
changing text, to changing colours, to changing the options available in a
drop-down list.
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Example embedded script in JavaScript to write one line to the page:
<script type="text/javascript">
<!-document.write("<i>Hello World!</i>");
//-->
</script>
The advantages of this type of language are as follows:
 User interface already exists so no need to create one.
 Ready-made, pre-tested functions already included as part of the language
for programmers to use thus saving time and effort.
 Uses for scripts:
– within a word processor – a script to insert a preformatted/customised
header and footer on every page of a document
– within a photo-editing program – a script to automatically apply pre-set
colour levels and filters (eg sepia) to set of photos
– within a database – a script to insert a customised company logo and
contact details on every report generated by the database.
Mark-up languages
Mark-up languages are designed for processing, defining and presenting text.
The language provides code for formatting the layout and style of a text file.
The code used to set the formatting is called a tag. HTML is a popular markup language. Below is an example of some basic HTML:
<!DOCTYPE html>
< html>
< head>
< title>Title of the document</title>
< /head>
< body>
The content of the document......
< /body>
< /html>
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Exercises
1.
Macros can be set up when using applications. Describe one method of
activating a macro.
2.
What type of language would be used to code a macro?
3.
Name an advantage of using a macro.
4.
Name a mark-up language commonly used to write web pages.
5.
Using a text editor and with guidance from staff, write a basic web
page in a mark-up language rather than using a graphical webdesign package. The web page can be on a topic of your choosing.
Remember to save the file twice: once as the basic text file and
once as an HTML file so that it can be viewed in a web browser.
6.
Do some further research of your own and try to find and
incorporate an additional feature into the web page you created in
question 5. For example, can you add sound or embed an
animation into the page? Do you know what a marquee is? Could
you get a marquee working on your page?
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Design and testing
Testing
Testing an information system involves looking at each function, checking that
it is of suitable quality and ensuring that all of the parts work on their own and
also together, matching the original design.
There are two main types of testing.
Screen testing
The tester looks at every screen to make sure it matches the design and
works as it should. Some standard screen tests are:
 Do the buttons do what they are supposed to do?
 Do all the texts, fonts, colours and sizes match the original design
specification?
 Does the video and audio run properly?
 Any spelling mistakes or typos?
Navigation testing
Some standard navigation tests are:
 Do all the internal links work?
 Do all external hyperlinks work?
Purpose, features, functionality and users
There must be a clear understanding of what a proposed information system
will do before construction begins. This is called the analysis stage and
involves answering questions such as the following:




What is the purpose of the information system?
Who will be using the information system?
What are the specific requirements?
What type of equipment will it run on?
Purpose
The designer of a new information system needs to consider what the system
aims to achieve when it is complete, what sort of content the system will
include and what type of user will be accessing it. For example, the purpose of
the system refers to whether the system is for business, leisure or educational
use and where the system will run, ie on the internet, on a mobile phone or on
a desktop computer.
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Features and functionality
A feature is what something has, and a function is what something can do. An
information system should feature a user-friendly interface; the function would
be to make it easier for the user to use that system. The features and
functionality an information system will have depend on what type of
information system it is, eg is it a website, presentation or mobile application?
In general, however, the designer considers things like what type of interface
the system will have (graphical or command line), whether or not the interface
is customisable, whether the system works online or offline, whether the
system uses video and/or sound, if the system is touch operated or uses a
mouse or keyboard etc.
Hardware and software requirements
Whatever system is created will have to be compatible with the user’s system,
therefore the designer will need to think about:




what specification of computer the user audience will have
what type of operating system the user computer will have
whether the user computer has sound and video capability
how much memory is installed and how fast the processor is.
User/audience
A new information system must meet the needs of the intended audience; if it
is not user-friendly or appealing, people will not use it. The designer must
consider the age, expertise, ability and language of the audience.
A novice user is one who has little experience of using information systems
and as such will require a simple ’cut-down’ user interface with clear icons and
menus, and a built-in help system.
An expert user will have lots of experience of using information systems and
as such will be happy to have access to a more complex and detailed
interface with more advanced features and the ability to use things like
keyboard shortcuts and commands rather than having to drill down through
menus and submenus.
The age of the user will affect the design of the system as well. An example of
this is that older users may be less dextrous and have poorer eyesight,
requiring bigger icons and buttons, and a higher contrast display.
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Exercises
1.
What are the two main areas that should be tested when looking at
an information system?
2.
Swap with a neighbour and look at the web page they created in the
previous section (questions 5 and 6). Create a checklist of things
you will test and proceed to fill that list in, giving your neighbour a
copy of the finished feedback and keeping a copy for yourself.
3.
Using examples, describe the difference between the functionality and
the features of a website.
4.
Describe what is meant by the purpose of an information system.
5.
Name and describe two factors a designer should consider when
planning and creating an information system.
6.
Take a well-known website of your choice and, on the computer or on
paper, make a list of the features and functions on the site.
7.
Swap with a neighbour and look at the website and list of features and
functions that they have identified in question 6. Tick or highlight the
ones you agree with and add any others you can think of. Keep your
neighbour’s work and be prepared to share your findings with the class.
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Hardware and software requirements
To be of use, a computer needs hardware and software.
Hardware refers to the physical (tangible) parts of the computer system like
the keyboard and mouse.
Software refers to the programs or instructions that control the hardware.
Hardware
Hardware can be grouped into input and output devices.
Input devices enable a user to interact with the computer. Brief descriptions of
some common input devices are given below.
Device
Description
Example of use
Digital camera
Captures light coming in from the lens
Digital images can be taken of an
and converts it into digital form and
event such as a birthday party and
stores it usually on SD memory card
then be transferred to a computer,
rather than traditional film.
edited and shared online with
others.
Microphone
Allows sound to be inputted to the
Recording narration for a video.
computer. Microphones are used to take
Used in conjunction with voice
a sound and convert it into an electrical
recognition software to give
signal for the computer.
commands to the computer or to
take the spoken word and convert
to text on screen.
Touchpad
Scanner
A small, flat pad which senses your
Similar to a mouse it can be used
finger movements and uses this to
to select items from a menu or
control the cursor on the screen and
highlight objects on screen to be
select icons and menus.
edited.
Used to input images to a system. A
Digitising a traditional photo on
light beam passes over the page or
photo paper so that it can be edited
photo and a sensor detects the light
and shared with others, for
being reflected. The image is then
example on a website.
stored in the system’s memory as binary
numbers.
Mouse
A pointing device used to interact with
Selecting items from a menu.
graphical user interfaces on screen.
Highlighting objects on screen to
be edited.
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Keyboard
A normal keyboard has keys for the
Typing an essay up in a word
letters of the alphabet, keys to produce
processor.
the digits from 0 to 9, keys to produce
Typing in numbers/data for a sales
all punctuation marks and special
spreadsheet.
command and function keys.
Typing in a web address (URL) for
a website.
Graphics
A flat plastic pad with sensors
Freehand drawing by artists into a
tablet
underneath the surface. The sensors
graphics package.
detect the movements of a pointing
device or stylus and move the cursor on
the screen accordingly.
Output devices enable a computer to communicate with the outside world.
Brief descriptions of some common output devices are given below.
Device
Description
Example of use
Inkjet printer
Uses ink cartridges and sprays fine jets
Home use to print off short letters
of ink onto the paper. Inkjet printers can
or colour photos.
produce high-quality printouts and are
quite cheap to purchase but are slower
than laser printers and the cost of ink
cartridges can be high.
Laser printer
Similar to a photocopier, a laser printer
Business use to print out long
uses electrostatically charged toner (ink
documents or multiple copies of
dust) cartridges instead of wet ink. Lser
reports quickly.
printers produce high-quality printouts
quickly, but are expensive to buy and
maintain.
Monitor
Used to display computer output.
To watch a movie that is being
Monitors can vary in size (measured in
streamed over the internet.
inches diagonally from corner to corner)
To read the input from a keyboard
and resolution (measured in amount of
as an essay is being typed.
pixels displayed on screen). The higher
the resolution, the clearer the image.
Monitors today are flat and can be LCD,
TFT or LED. LED screens are the most
efficient of the three in terms of electricity
consumption.
Speakers
These are used for outputting sound;
To provide sound for a multimedia
how loud the speakers are is generally
presentation.
measured in watts.
To allow the user to hear the
dialogue in a DVD being played on
the computer.
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Graphics
These cards have on-board memory that
Allows a user to play high-quality
card
is dedicated to handling graphics. This
first-person shooter games.
relieves the main CPU, allowing it to
Allows a user to edit and produce
concentrate on other tasks. The graphics
high-definition video.
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.
Sound card
Similar to a graphics card, sound cards
Allows a user to enjoy high-quality
have on-board memory that is dedicated
immersive surround sound whilst
to handling sound, relieving the main
playing first-person shooter games.
CPU and allowing it to concentrate on
Allows a user to edit and produce
other tasks. The sound card takes digital
high-quality audio.
information about the sound stored in the
RAM sends it out to speakers.
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SUBJECT CONTENT
Exercises
1.
What does the L in LCD stand for?
A
B
C
D
2.
What is the smallest measure of storage size?
A
B
C
D
3.
Kilobyte
Megabyte
Byte
Bit
Which of these is an input device?
A
B
C
D
4.
Lighter
Links
Liquid
Laser
Speakers
Monitor
Digital camera
Printer
Which of these is an output device?
A
B
C
D
Scanner
Mouse
Keyboard
Monitor
5.
In pairs, pick an input device of your choice and produce an animation,
slideshow or podcast describing it. One person must do research and
produce the information on the device description whilst the other should
research and produce the information for possible uses for the device.
6.
Pair up with another group who have picked a different device to you,
watch each other’s pieces and be prepared for anyone in the new larger
group to share what they have learned from one another with the rest of
the class.
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Computer architecture
Processor
The processor is the brain of the computer, controlling everything that takes
place on the computer. 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 basic measure of the power of a computer is processor or clock speed.
Currently measured in gigahertz (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 mentioned earlier 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.
Memory
If the processor is the brain of the computer, the memory of the computer
could be compared to its muscles. 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. Read-only memory (ROM) stores a small part of the operating
system called the bootstrap loader. When a computer is powered on, the
bootstrap loader pulls the computer up by its bootstraps, finding the rest of
operating system in backing storage and loading it into the faster RAM.
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 powered down.
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Exercises
1.
Which part of the computer controls everything that happens within it?
2.
What is the name of the basic measure of a computer processor’s
performance?
3.
What is the unit of measurement for the measure mentioned in question
2?
4.
Research and list three different companies that manufacture computer
processors.
5.
Which one of these statements about RAM and ROM is true?
A
B
C
D
Neither ROM nor RAM holds data when the power is switched off.
RAM holds data when the power is switched off and ROM doesn't.
The user can write data to RAM but not to ROM.
The user can write data to ROM but not to RAM.
6.
Which generally holds more data, RAM or ROM?
7.
When a computer is first switched on, which type of memory is read from
first and why?
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Types of computer
Computers come in different shapes and sizes designed for different users
and situations The main categories are listed below.
Embedded
These are small computers built into other devices, such as cars, mobile
phones and microwave ovens. They can be controlled in some cases with
simple touchpads or screens, such as the touchpad buttons on the front of a
microwave oven. Some embedded systems might provide output, for example
if the device is a microwave the output device might be the LED counting
down the seconds of cooking time left on the front of the oven. The portability
of an embedded system depends on the size and weight of the device the
computer is embedded into. If the computer is inside a washing machine it
won’t be portable.
Smartphone
Smartphones are mobile phones that contain a number of convergent
technologies. Modern smartphones allow users to send and receive email,
surf the world wide web, take and edit digital photos and videos, play MP3s,
access e-books, watch movies, play games and carry out many other tasks
that users might traditionally perform on a desktop computer. Smartphones
have an LED touchscreen or mini qwerty keyboard and built-in speakers.
Many have one or more built-in cameras. The phones are generally pocketsized but at the time of writing, a trend for slightly larger phones with larger
screens is emerging. Smartphones run off a battery for a number of hours.
Tablets
These are book-sized computers with a touchscreen or attachable compact
keyboard on some types. Many tablets have one or more built-in cameras for
things like video conferencing. For output devices tablets have LED displays
and built-in speakers. Tablets are light and portable but not pocket–sized, and
they are able to run off a battery for a number of hours.
Laptop
Traditionally operated using a keyboard and track pad, many laptops have
built-in webcams. Some new laptops now come with touchscreens as well. In
terms of output devices, laptops have LED displays and built-in speakers.
Laptops are portable enough to fit in a backpack or special laptop case, and
run off a battery for a number of hours. Larger laptops will contain an optical
DVD or blu-ray drive.
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Desktop computer
These computers are not portable and are powered by mains electricity rather
than by battery. A desktop will have a monitor, full-sized keyboard, mouse and
optical DVD or blu-ray drive.
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.
Both types of computer have a massive amount of memory, multiple powerful
processors and can allow a number of users to access the system at once.
Server
In client/server networks, one computer acts as a central resource for the
others. A server is the central computer on this network. Servers generally
have multiple fast processors, lots of RAM and a greater amount of backing
storage (hard drive) than the client computers it serves on the network.
Servers can have specific tasks on the network such as storing and backing
up all of the files centrally for the users on the network and controlling access
to the internet and email. Similar to mainframes, servers are generally located
in a secure room or cupboard and combined with the additional networking
racks the servers require they it can take up a substantial amount of physical
space.
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Exercises
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.
4.
Using the internet research embedded devices and create a
presentation, web page, podcast or poster on a particular kind of
embedded device of your choice. What is it embedded into? What
is its function?
5.
Look at your neighbour’s submission for question 4. Is there any
other information you would like to know that is missing? Feed
back to your neighbour two things you liked about the piece and
one area that could be improved on.
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Operating systems
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 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. The operating system
co-ordinates and manages all of the computer's activities, looking after things
like where files are saved, how much RAM a program needs to carry out a
task, customising the interface to suit the needs of the user and handling any
hardware that is plugged into the system.
Operating systems are large programs that can take up a large amount of disk
space and require a lot of RAM. Different types of computer can require their
own type of operating system, for example Apple computers use a different
operating system to normal personal computers. In addition to this, some
operating systems are called open source and can be freely downloaded and
then re-programmed or customised whilst others have to be paid for and the
source code is closed or locked down and can’t be reprogrammed by the user.
The operating systems that run on mobile phones and tablets are a little
different to the ones found on a normal desktop computer. A mobile phone or
tablet operating system will have be able to run on different and in some cases
less powerful processors. It will also have to deal with input from a different
range of input devices and because the devices are battery powered,
managing power consumption will be particularly important.
Large organisations like banks and government departments will require an
operating system that allows lots of users to communicate and share files over
a network and will have to incorporate enhanced security, backup and user
management features.
Exercises
1.
With a partner, research and list as many operating systems as you can.
2.
Swap your list from question 1 with another group, 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?
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Backing storage devices
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
Random/direct
Sequential/serial
Backing storage device
Hard disk drive, memory cards, flash drive, CD, DVD
and blu-ray drives
Magnetic tape drive
Hard disk drive – magnetic drive
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).
Traditional hard disks have spinning platters and a moving read head, but
recently companies have started to produce solid state hard disks which do
not have any moving parts and are therefore smaller, use less power and are
more reliable.
Flash drive
Small and portable, this type of backing storage plugs into the USB port of a
computer and can store gigabytes-worth of data, making them a convenient
way of keeping a backup copy of files and of transferring files from one
computer to another.
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.
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Optical disks
These disks use lasers to read data ‘burnt’ onto the disk surface. Disks can be
ROM, recordable or rewritable. ROM disks can only be read from and can’t be
written to, recordable disks can generally only be written to once and
rewritable disks allow users to write over the disk multiple times as you might
a flash drive. CDs store around 700MB of data, DVDs about 4GB and blu-rays
about 25GB.
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.
Interface type and speed
When discussing backing storage, the interface refers to how the device
communicates with the processor. The most common interface is USB. 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.
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Exercises
1.
Which of these is a backing storage device?
A
B
C
D
Scanner
Flash drive
Printer
Speakers
2.
What type of access is used by a magnetic tape drive?
3.
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.
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.
5.
What is meant by the term ‘solid state’?
6.
Add two other columns to the table created in question 3, adding
any information you can find about the interface type and speed of
the backing storage types mentioned.
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Networking/connectivity
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.
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.
Advantages of networking
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.
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 networks
(LANs) are groups of computers in close proximity to each other, such as in an
office building, a school or at home. Wide area networks (WANs) cover a large
geographic area, such as a city, county or country. The internet is a global
network of networks where many LANs and WANs are interconnected.
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Wired, optical and wireless networks
Wired networks use cables to transfer data between computers and devices.
The type of wire used can have an effect on how fast the data can be sent and
received. The most common type of networking cable is twisted pair or
ethernet cabling, which can support quite high transmission speeds, but the
fastest type of cabling is fibre-optic, which uses light signals. The downside to
fibre-optic cabling is that it is more expensive than twisted pair.
Wireless networking involves computers and devices communicating with one
another without any cabling. Common types of wireless networking methods
are Bluetooth and wi-fi. Wireless technology allows you to move around a
building and still be connected to the network. A wireless network requires
each computer to be fitted with a wireless network card and to be within range
of a wireless hub or router. 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.
Cloud computing
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.
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Exercises
1.
When two computers are linked together it is called:
A
B
C
D
2.
A server controls:
A
B
C
D
3.
the world wide web
the internet
a server
a network
switching on a computer
the running of a network
switching off a computer
the running of computers
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.
5.
Name two types of wireless network technology.
6.
Name two kinds of network media.
7.
Research a company that provides cloud computing services and
produce a report or presentation profiling that company.
8.
With a partner, create a presentation, poster, animation or podcast
detailing the advantages and disadvantages of cloud computing.
One team member should be responsible for the advantages and
another should be responsible for the disadvantages. When you
are both finished have a discussion and try to agree as a pair
whether the advantages outweigh the disadvantages.
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Security risks
When computers are connected together in a network the benefits are
numerous. However, there are risks to computers being interconnected. A
major problem can be viruses. A virus is a program that when run infects a
computer system, causing damage or disruption to the system. As well as
viruses there are two other types of file that can cause disruption on a
network: worms and trojans. Worms, once activated, copy themselves
automatically and very quickly between computers on a network, causing a
bottleneck on the network. Trojans are programs that might perform a normal
process on the computer but underneath secretly perform another, possibly
harmful, process at the same time.
Denial of service attacks are when individuals target networks and try to bring
them to a standstill by activating programs like worms or bombarding the
network with bogus requests, both of which keep the network so busy that the
normal activity on the network cannot continue. A denial of service attack can
cost organisations lots of money in terms of lost business, damaged reputation
and wasted manpower.
Hacking
Hackers can be likened to digital burglars using a network to gain
unauthorised access to other people’s computer systems in order to place
viruses, copy or delete data.
Spyware
Spyware is software that secretly records the activities of an unsuspecting
computer user. The majority of spyware is malicious, aiming to capture
passwords, banking and credit card details, and send them over the internet to
fraudsters.
Keylogger
A keylogger is a type of surveillance software that can record every keystroke
made by a user and save it to a file. A keylogger recorder can record instant
messages, email and any information typed at any time on the user’s
keyboard. The file created by the keylogger can then be sent back over the
network to, for example, a fraudster.
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Phishing
Phishing is the act of fooling a computer user into submitting personal
information by creating a fake website that looks like a real (and trusted) site.
It is a hacking technique to ‘fish’ for passwords and other secret financial
information.
Software security measures
Antivirus software
A group of programs devised to stop or find and remove viruses from
computer systems. To be most effective, antivirus software should be running
all the time, scanning the system, checking for tell-tale virus signatures or
suspicious virus-like activity.
Firewalls
A firewall is a program or piece of hardware that helps stop hackers, viruses
and worms from entering a computer over the internet.
Security suites
A collection of programs controlled by a single control panel that provides the
user with a number of functions in one place, including antivirus, firewall,
antispam, parental controls, website authentication, password storage and
protection against identity theft. Some security suites also include backup and
computer tune-up services.
User identities (IDs) and passwords
Only authorised users are issued with the IDs and passwords that are needed
to gain entry to the network. When users log on, the computer system checks
their IDs and passwords, and tries to match them with those on file. Users only
gain access to the network if the IDs and passwords they have entered match
those kept on the system.
Biometrics
Some systems use biometric technology to ensure that only authorised users
gain access to a network. Biometric security involves storing data about
fingerprints, voices or people’s eyes on special smart cards.
Encryption
Encryption is the encoding of data held on the system. This means that if the
network is hacked into the data are meaningless to the hacker because they
do not have the security key to unlock or decipher the encrypted data.
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Exercises
1.
Which statement about viruses is true?
A
B
C
D
Only networked computers can be affected by viruses.
The best method of avoiding viruses is to use antivirus software.
All viruses delete data from the user’s hard disc.
Viruses can only be spread by sharing USB flash drives.
2.
State one way of spreading computer viruses.
3.
Describe one common symptom of a computer virus.
4.
What is the name given to gaining unauthorised access to another
person’s computer?
5.
Apart from hacking and viruses, name two other threats to
computer systems.
6.
Name two kinds of biometric security measure.
7.
If a computer has been hacked and data has been stolen how else
could that data be made secure?
8.
Name three services that could be included in a security suite.
9.
Describe what is meant by a denial of service attack.
10.
Research a recent news story about computer security. Was there
any damage or loss of data? Who was involved? Was the issue
resolved? Write a short report or presentation detailing your
findings. Swap with a neighbour after you have finished and read
their piece.
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Computers and the law
With the advent of computers new laws were created to tackle issues that
arose.
The Data Protection Act
Companies and organisations like the government hold a lot of personal data
about individuals. To protect this data and people’s rights, the Data Protection
Act was passed by Parliament to protect peoples’ privacy. In short the law
states that:
 all data held on a computer must be registered with the Data Protection
Agency
 if a data subject wishes to inspect data held about themselves they can
request to see their own personal data
 if data held about data subject is incorrect they can demand it is changed
 the data user is obliged to keep the data safe, secure and up to date, and
not to hold the data for longer than is necessary.
The Computer Misuse Act
This law makes it illegal to gain access to a computer without permission from
the owner. The Act also makes it illegal to create or deliberately spread
viruses that cause deliberate damage to computers.
Copyright Designs and Patents Act
The Copyright Designs and Patents Act makes it illegal:
 to make unauthorised copies of software that is copyright protected
 to send software over a network and copy it without the permission of the
licence holder
 to run unauthorised copies of software on a computer or network.
Health and safety
There are a number of health problems that can arise when working at a
computer for long periods. Repetitive strain injury (RSI), backache, headaches
and eyestrain are all conditions that can occur. By using the correct
equipment, good working practices and good posture these conditions can be
avoided.
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Repetitive strain injury
RSI occurs when the joints in the fingers constantly tap away at the keyboard.
The symptoms of RSI are pain in the joints of the hand. RSI can be avoided by
using an ergonomically designed keyboard in a good position coupled with
frequent breaks from typing and a good typing technique. Computer users can
also purchase gel wrist pads which support the typist at the keyboard.
Eyestrain
The symptoms of eyestrain can be blurred vision and irritated eyes, and can
be avoided by the computer user looking away from the screen at regular
intervals and focusing on a distant object.
Health and safety law
Because of the health issues mentioned above employers are now required by
law to provide the following:
 training – employees should have access to training on health and safety
issues
 eye tests – computer users should receive regular free eye tests with
spectacles provided at the employer’s expense if required
 inspections – chairs, computers and work areas should be regularly
inspected to make sure that they are up to standard
 tasks – employers should design their employees’ working day so that
workers can have regular breaks from computer-based activity.
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Exercises
1.
Name the law that makes hacking and creating viruses a crime.
2.
Name and describe a health and safety measure employers must
take to help their employees when using computing equipment.
3.
State the law that protects a company logo from being used by
another company without permission.
4.
Name and describe a health problem that can occur when using a
computer.
5.
Research a piece of hardware or equipment that prevents a
particular health issue when using computers. Present your
findings in a presentation or report.
6.
Describe what a company must do to adhere to the Data Protection
Act.
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Computers and the environment
Carbon footprint
A carbon footprint measures the amount of greenhouse gases emitted during
the production and use of a product, in this case computer equipment.
Using the internet consumes energy at the user end but also involves
electricity usage and therefore carbon emissions by the companies that run
the websites users view.
On the plus side, computers can help reduce carbon emissions by making
equipment more efficient. An example of this would be modern enginemanagement systems on cars that control the car engine to make it more fuel
efficient.
Modern manufacturers of IT equipment are constantly looking for ways to
reduce the energy consumption of devices from low–power-consumption
processors to low-energy-rated LED monitors.
With modern advances in networking, employees can telecommute, which
means that they can work from home without having to physically commute by
car, bus or train. Similarly, organisations can save money and the environment
by holding meetings using teleconferencing. Teleconferencing involves people
meeting together using webcams and microphones instead of having to leave
their normal office and travel to another city or country to meet with colleagues
or customers.
Disposal of IT equipment
What is WEEE?
WEEE is waste electronic and electrical equipment like TVs, fridges and
computers. Many smaller items slip through the net and are not treated or
recycled and get buried in landfill sites. This wastes resources and puts a
major strain on the environment.
Stores that sell electrical equipment should provide facilities to take back
WEEE. They must either offer in-store take-back or be a part of a distributor
take-back scheme (and so tell customers where to take it). There should also
be information in stores about the environmental impact of WEEE and what
customers can do to help reduce the impact their purchases make on the
environment.
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Consumers should consider the environmental consequences before
replacing mobile phones, computers or other gadgets. Could the equipment
be upgraded or a refurbished product be bought instead?
Computer equipment can contain lead and other hazardous materials such as
mercury and cadmium . Among the risks when exposed to these materials are
lead poisoning, high blood pressure, iron-poor blood, liver disease, nerve and
brain damage, and cancer. Because of the dangers involved with having these
devices lying around in public landfills, it is important to dispose of equipment
responsibly.
Besides environmental concerns, a risk of not disposing of equipment properly
is identity theft. Identity theft is one of the fastest growing crimes, involving
information such as names, addresses, bank and credit card information, and
social security numbers being illegally obtained from, for example, old
computer systems not properly disposed of. Identity theft can result in
damaged reputation and credit rating. Victims of identity theft may have to
deal with such effects as denied loans or credit, lost job opportunities, being
harassed by credit agencies and even being arrested for crimes they did not
commit. Recovering from identity theft can be both time-consuming and costly.
Exercises
1.
What does a carbon footprint measure?
2.
Name two risks when disposing of old computer equipment.
3.
Research on the internet or using computing magazines to find an
energy efficient computer. Produce a poster, animation or
presentation advertising the energy-efficient features of the
computer you have found.
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Glossary
Below is a glossary of common computing terms that you may come across
during your studies.
Analysis
The analysis stage involves reading and
understanding a problem.
Animation
File made up of moving images.
Application software
Comprises all the programs you apply to a task
such as writing a report or sending an email.
Applications package
Software that performs a particular task such
as word processing or desktop publishing.
Arithmetic/logic unit(ALU)
Component of the processor of a computer
that does the calculations and makes the
decisions.
ASCII
A 7-bit code allowing 128 different characters
to be represented.
Back up
A second copy, kept separate from the original,
of a program or file made in case the original is
lost or damaged.
Backing storage
Permanently holds data on media such as disk
or memory card.
Backing storage medium
The physical item which holds data such as
USB pen drive.
Binary
Counting using two digits, 1 and 0.
Binary language
Machine language represented using a series
of 0s and 1s.
Biometrics
Security method using physical characteristics
to identify a user such as fingerprints, retinal
scan or voiceprint.
Bit
A binary digit, either one (1) or zero (0).
Broadband connection
A high-speed internet connection.
Byte
A collection of eight bits.
Central processing unit
(CPU)
The hardware component that processes data.
Computer system
A combination of all the components required
to process and store data using a computer.
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Control unit
Controls parts of the processor and ensures
instructions are in the correct order.
Cropping
Taking away part of a graphic.
Debugging
The process of finding and correcting program
errors.
Documentation
All the supporting paperwork for a program.
DTP
Desktop publishing.
Embedded system
Minicomputer inside another piece of
equipment such as a car or a mobile phone.
Encryption
Formatting a message into a secret code so
that it can’t be understood by anyone who is
not authorised to view it.
Evaluation
Evaluation involves reviewing a solution
against a checklist of requirements,
highlighting any strengths, weaknesses and
improvements needed.
Exceptional test data
Test data that should be rejected by the
program.
Extreme test data
Test data that is on the limit of acceptability.
Field
A single item of data stored in a record.
File management
A function of an operating system dealing with
how files are held, controlling the process of
saving or loading files from disk.
File server
Central disk storage for users' programs on
network.
Flowchart
A pictorial representation of the logical steps it
takes to solve a problem.
Graphical user interface
(GUI)
Allows users to interact with a program in a
graphical environment.
Hardware
The equipment or physical devices that are
associated with a computer.
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Hotspot
An area of a graphics or piece of text that
performs a function when selected. Hot spots
are particularly common in multimedia
applications, where selecting a hot spot can
make the application display a picture, run a
video or open a new window of information.
HTML
Hypertext mark-up language – the language
used to write web pages.
Human computer
interface (HCI)
The means by which a computer and user
communicate.
Hyperlink
Links between web pages, documents or files
activated by clicking on text or on a particular
area of the screen, such as a graphic.
Icons
Symbols or pictures on a screen.
Import
To bring in data from one program file to
another.
Information
Data that has been processed.
Inkjet printer
Reproduces images using dots produced by
tiny jets of inks.
Input
Describes the entry of data items into
computer memory using hardware devices
such as a keyboard or mouse.
Input device
Allows data to be entered, such as a scanner
or a mouse.
Interface
Part of a computer system that allows different
devices to communicate with the processor by
compensating for any differences in their
operation.
Internet
Area network spanning the globe.
LCD
Liquid crystal display.
Local area network (LAN)
A network within a single room or building.
Macro
A set of commands activated by a single
keystroke.
Mailbox
Where electronic mail is stored while waiting to
be read/downloaded.
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Menu
List on-screen from which choices may be
made by the user.
Monitor
Output device to view computer activity.
Non-volatile
Describes storage whose contents are retained
when power is lost.
Online help
Help available in the form of information
screens built into the program being used.
Online tutorial
Step-by-step lessons on how to use a
computer program.
Operating system
Programs which control the operation of a
computer system.
Optical character
recognition (OCR)
Characters on paper can be digitised into an
editable document for use on a computer.
Optical storage
A form of non-magnetic storage read by a laser
beam being reflected off the pits and bumps on
the disk surface.
Output
Describes the operation of retrieving
information from memory and sending it to a
device, such as a monitor or printer, so people
can view, interpret and use the results.
Output device
A device which displays data from a computer
system, such as a printer.
Palmtop
A hand-held computer with an LCD screen
using a stylus and touchscreen for input.
Password
A secret code used to gain access to private
information on a computer system or to log on
to a network.
Peripheral
A device attached to a computer for input,
output or backing storage.
Pixel
Short for picture element; small dots used to
make up a picture on a screen.
PPM
The speed at which a printer can output pages
of print, measured in pages per minute.
Processing data items
May involve organising items, checking them
for accuracy or performing calculations with
them.
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Processor
The part of a computer that carries out the
process.
Program
A list of instructions that tell the computer what
to do.
Random access
Files are accessed directly.
Random access memory
(RAM)
Computer chip that stores data temporarily;
data are lost when the computer is powered
down.
Read-only memory (ROM)
Computer chip that stores data permanently:
data are not lost when the computer Is
powered down.
Record
Data structure consisting of multiple fields of
information.
Registers
Fast-access memory locations inside a
processor.
Resolution
Quality of a picture: more pixels mean better
quality.
Rich text format
Stores information about text, including
formatting.
Rotate
Turn a graphic or picture around.
Scale
Making a graphic smaller or bigger.
Scanner
Input device that allows printed text/graphics to
be digitised.
Scrolling
Moving the display on the screen using cursor
keys or mouse.
Sequential access
Files are accessed one after another.
Software
Instructions that tell the hardware what to do.
Speaker
Output device allowing sound to be produced
by a device.
Spellchecker
Software feature that compares the words in a
document with the words in an electronic
dictionary and offers alternatives if no match is
found.
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Spreadsheet
A program used for numeric data, calculations
and graphs divided into rows and columns.
The individual cells in a spreadsheet can
contain text, numbers and formulae.
Standard file formats
A way of storing data for use by a number of
different application packages.
Technical guide
Contains the installation instructions and
technical requirements of a piece of software.
Template
Ready-made structure/layout for a document.
Text editor
Allows source program code to be entered and
changed.
Transition
How one slide, page or scene changes to
another.
Translator
Converts a high-level language program into
low-level machine code so the processor can
use it.
User guide
Explains the functions and features of a piece
of software.
Username
The means of identifying a user on a computer
system or network.
Validation
A check carried out by the computer on any
data to see if it is unreasonable or incomplete,
for example to see if a value is within a range
(range check).
Viruses
A harmful piece of software that attaches itself
to a file, reproduces and spreads.
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Qualifications
The requirements for a qualification in Computing Science National 4 or
National 5 are laid out in the SQA documentation, which can be accessed
from http://www.sqa.org.uk/sqa/48477.html.
To gain a course award, a learner must pass all units as well as the Value
Added Unit at National 4 or the course assessment at National 5. The course
assessment will contain the Added Value Unit and will consist of a question
paper and an assignment. The assignment will be assessed under controlled
conditions and marked externally.
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