Unit 18: Software Design - OneFilequals.onefile.co.uk/pdf/unit/EBIIT_018.pdf · Unit 18: Software Design Unit code: T/601/5110 ... P5 design a software solution to a business requirement

203Edexcel BTEC Level 2 Firsts specification in Information Technology– Issue 1 – August 2010 © Edexcel Limited 2010

Unit 18: Software Design

Unit code: T/601/5110

QCF Level 2: BTEC First

Credit value: 10

Guided learning hours: 60

Aim and purpose

The aim of this unit is to ensure that learners know the software development process and the features of programming languages, and are able to use design tools to develop software solutions.

Unit introduction

There is a comprehensive range of generic application software and utilities available to businesses across many different sectors. Examples are spreadsheets and databases, as well as more focused packages such as payroll or computer-aided design (CAD). Sometimes, however, a business need is identified that cannot be addressed in this way, and in these situations it is necessary to build a solution using an appropriate computer language.

In order to develop a programmed software solution which meets business and user needs it is first necessary to understand the problem and be very clear in terms of user requirements. Problems are often caused by, poor understanding of user need, as well as poor planning and learners will need to be able to choose the programming language which best address the user need. A wide range of different languages is available with quite different characteristics and features. Learners will probably focus on one particular language in another unit, but in this unit they will build an appreciation of why different high-level languages are available and why they are chosen in particular situations.

The unit focuses on the design process and would be an appropriate place to start before undertake focused programming language units. The unit examines the business context within which solutions can be developed along with possible constraints.

A major part of learners’ time will be spent on familiarising themselves with fundamental design tools such as data flow diagrams and algorithms. This will gives learners a firm foundation to undertake the focused programming units.

Learning outcomes

On completion of this unit a learner should:

1 Know the features of programming languages

2 Know the software development process

3 Be able to design software development solutions.

Edexcel BTEC Level 2 Firsts specification in Information Technology– Issue 1 – August 2010 © Edexcel Limited 2010204

Unit content

1 Know the features of programming languages

Programming paradigms: procedural; object oriented; event driven; characteristics eg procedures, functions, events, objects

Features: sequence; selection eg case, it…then…else; iteration eg repeat – until, while ...do; variables eg naming conventions, local and global variables, logical operators; assignment statements; input statements; output statements

Types of language: visual languages; other eg script and markup languages; simple overviews and uses

Choice of language: reasons eg organisational policy, suitability in terms of available features and tools, availability of trained staff, reliability, development and maintenance costs, expandability

2 Know the software development process

Software development life-cycle: requirements gathering, specification eg scope, inputs, outputs, processing, user interface, constraints eg hardware platforms, timescales for development; design; code; test; maintain

3 Be able to design software development solutions

Design: structure eg functions, procedures, objects; data; files

Tools: range of tools eg storyboards, narratives, action lists, graphical tools eg structure diagrams, data flow diagrams, entity relationship models; algorithms eg structured English, pseudo code

Data: types eg text, integer, floating point, byte, date, Boolean, other eg char, smallint

Software structures: eg functions, procedures, classes and objects; abstraction of data; pre-defined code; readability eg comments, appropriate names for variables, indentation; quality of code eg efficiency, reliability, robustness, usability, portability, maintainability

Review: against specifications requirements


Assessment and grading criteria

In order to pass this unit, the evidence that learners present for assessment needs to demonstrate that they can meet all the learning outcomes for the unit. The assessment criteria for a pass grade describe the level of achievement required to pass this unit.

Assessment and grading criteria

To achieve a pass grade the evidence must show that the learner is able to:

To achieve a merit grade the evidence must show that, in addition to the pass criteria, the learner is able to:

To achieve a distinction grade the evidence must show that, in addition to the pass and merit criteria, the learner is able to:

P1 describe the characteristics of programming paradigms

M1 describe the features of programming languages, including how sequence, selection and iteration are used

P2 identify the factors influencing choice of programming language

P3 describe the stages of the software development life-cycle

P4 outline a specification for a business requirement[IE1]

M2 select and justify the programming language to be used[IE6, CT2]

P5 design a software solution to a business requirement using appropriate design tools [CT1, EP3]

M3 describe the data types and software structures used in a design solution.

D1 develop algorithms to represent a design solution[IE1]

P6 review the design against the original requirement.[IE4]

D2 evaluate the design tools used.[IE4]

PLTS: This summary references where applicable, in the square brackets, the elements of the personal, learning and thinking skills applicable in the pass criteria. It identifies opportunities for learners to demonstrate effective application of the referenced elements of the skills.

Key IE – independent enquirers

CT – creative thinkers

RL – reflective learners

TW – team workers

SM – self-managers

EP – effective participators


Essential guidance for tutors

Delivery

Ideally this unit will be delivered alongside one of the programming units to put the theory into context. In many ways it is an introduction to systems analysis as many of the design tools used for systems analysis, such as data flow diagrams, are included.

Delivery can follow the order of the learning outcomes, starting with an introduction to programming languages and their features. This will be easier to bring to life if simple examples using different languages can be developed and learners able to experiment themselves. It is important that learners grasp the differences between types of languages and when each type is most appropriate.

Introducing the software development life-cycle broadens the learning to start looking at business requirements and how the whole process gets going and reaches completion. Case studies will be useful here, although a visiting speaker with first hand experience would be even better. Learners should practise writing each part of a specification. Lots of detail is not required at this level, learners just need an appreciation of the elements of a specification and an outline of what should be included.

Learning to use different tools to help design a programming solution will take some time and a lot of practise. If a particular language is to be used in another unit then this unit can concentrate on the particular design features appropriate to that language. Exemplar material would be useful. Structured English and pseudo code are principally Level 3 skills so need only be very basic at Level 2. Their use is required only to achieve at distinction grade.

Learners will probably be familiar with reviews and evaluations but time should always be allowed to practise these skills before undertaking assessment.

Outline learning plan

The outline learning plan has been included in this unit as guidance and can be used in conjunction with the programme of suggested assignments.

The outline learning plan demonstrates one way in planning the delivery and assessment of this unit.

Topic and suggested assignments/activities and assessment

Introduction to the unit

Features of programming languages:

individual exercise – tutor assessing current level of knowledge

whole-class exercise – tutor presentation on programming languages – type, when used, why used

whole-class exercise – tutor presentation on programming features, followed by practical exercises

whole-class exercise – tutor presentation on data types, followed by practical exercises

mixture of tutor-led demonstration and learner exercises, repeated over a number of sessions.

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Development life-cycle:

whole-class exercise – tutor presentation on life-cycle

whole-class exercise – tutor presentation on determining the requirement, followed by individual exercise

mixture of tutor-led instruction, directed learning, practical exercises.

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Topic and suggested assignments/activities and assessment

Assignment 1 – Why Program?

Design tools:

whole-class exercise – tutor presentation on structures, followed by practical exercises

whole-class exercise – tutor presentation on tool, followed by practical exercises

whole-class exercise – tutor presentation on data, followed by practical exercises

mixture of tutor-led instruction, directed learning, practical exercises.

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Assignment 2 – Specification

Design evaluation:

whole-class exercise – tutor-led revision of evaluation techniques.●

Assignment 3 – Design

Assessment

It is suggested that this unit is assessed using three assignments as summarised in the Programme of suggested assignments table which follows this guidance.

Learners will need a realistic business problem for which a simple, programmable solution is an option.

To achieve a pass grade, learners must achieve the pass criteria listed in the assessment and grading criteria grid.

The first three pass criteria and associated merit criterion are theoretical in nature but should be set within a particular business context. The suggestion is that this is evidenced by a presentation to a business explaining why programming is the answer and how they would go about implementing it.

For P1, P2 and P3 learners should refer to the unit content to ensure coverage. This is straightforward descriptive work so interest may be added by suggesting different formats for presenting the information.

P4 requires a specification, which should include the elements highlighted in the unit content but does not need to be in great detail.

For P5, learners must generate a set of documents demonstrating the design solution. This could include some or all of: data flow diagrams, data dictionaries, entity relationship diagrams, flow charts, structured English, pseudocode or others. The design needs to be clear and the appropriate tools used.

P6 is a review of the design solution against the specification. Have all the objectives been met? If not, why not. Could the design be improved?

To achieve a merit grade, learners must achieve the pass grade criteria and the merit criteria.

M1 is an extension of P1 and the elements required are in the unit content. Learners should give examples of sequence, selection and iteration.

M2 will probably be included within the evidence for P4 and learners should use reasoned arguments as to why a particular language has been chosen.

M3 is a fairly straightforward extension of P5 and should cover the elements outlined in the unit content.


To achieve a distinction grade learners must achieve all the pass and merit criteria and the distinction criteria.

D1 is part of the design process and requires learners to include an algorithm such as pseudo code in the design documents.

For D2, learners are evaluating the design tools, ie DFDs etc, as distinct from the design itself which is reviewed for P6. This evaluation should include how well learners felt they used the tools and if the were useful.

Programme of suggested assignments

The table below shows a programme of suggested assignments that cover the pass, merit and distinction criteria in the assessment and grading grid. This is for guidance and it is recommended that centres either write their own assignments or adapt any Edexcel assignments to meet local needs and resources.

Criteria covered Assignment title Scenario Assessment method

P1, P2, P3, M1 Why Program? A small business has requested a software solution to a marketing analysis procedure. You have decided a programmed solution is best but must convince the management. Present your reasons to the board and explain the stages of development.

Presentation

Supporting documents

P4, M2 Specification Produce a requirements specification and select a programming language.

Specification

P5, P6, M3, D1, D2 Design Generate the program design and review and evaluate the design and the design tools used.

Design documentation, eg DFD, ERD, structured English

Evaluation

Links to National Occupational Standards, other BTEC units, other BTEC qualifi cations and other relevant units and qualifi cations

This unit forms part of the BTEC in IT sector suite. This unit has particular links with the following unit titles in the IT suite:

Level 1 Level 2 Level 3

Unit 6: Software Design and Development

Essential resources

Learners will need access to appropriate hardware and software development environment for practical programming tasks with online help and/or manuals, eg Visual Basic (any variety), JavaScript, Pascal.


Employer engagement and vocational contexts

The use of vocational context is essential in the delivery and assessment of this unit. Learners will require access to computer equipment to enable them to gain a practical awareness and enable them to apply their knowledge and understanding in a practical situation.

There is a range of organisations that may be able to help to centres engage and involve local employers in the delivery of this unit, for example:

Learning and Skills Network – www.vocationallearning.org.uk

Local, regional business links – www.businesslink.gov.uk

National Education and Business Partnership Network – www.nebpn.org

Network for Science, Technology, Engineering and Maths Network Ambassadors Scheme – www.stemnet.org.uk

Work-based learning guidance – www.aimhighersw.ac.uk/wbl.htm

Work Experience/Workplace learning frameworks – Centre for Education and Industry (CEI University of Warwick) – www.warwick.ac.uk/wie/cei.

Indicative reading for learners

Textbooks

Bowman K – Systems Analysis: A Beginner’s Guide (Paperback)

Flanagan D – JavaScript Pocket Reference (O’Reilly, 2002) ISBN 0596004117

Wang W – Visual Basic 6 for Dummies (Hungry Minds Inc US, 1998) ISBN 0764503707

Willis T, Reynolds M, Crossland J and Blair R – Beginning VB.NET (Wrox Press Ltd, 2002) ISBN 1861007612

Websites

http://visualbasic.about.com/

www.guidetoprogramming.com/joomla153/

www.profsr.com/

www.vbexplorer.com/VBExplorer/VBExplorer.asp

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Delivery of personal, learning and thinking skills

The table below identifies the opportunities for personal, learning and thinking skills (PLTS) that have been included within the pass assessment criteria of this unit.

Skill When learners are …

Independent enquirers identifying questions to answer and problems to resolve when outlining a specification for a business requirement

analysing and evaluating the design against the original requirement, judging its relevance and value

Creative thinkers generating ideas and exploring possibilities when designing a software solution to a business requirement using appropriate design tools

Effective participators proposing practical ways forward when designing a software solution to a business requirement, and breaking these down into manageable steps.

Although PLTS are identified within this unit as an inherent part of the assessment criteria, there are further opportunities to develop a range of PLTS through various approaches to teaching and learning.


Independent enquirers supporting conclusions when justifying a programming language

identifying questions to answer and problems to resolve when developing algorithms to represent a design solution

analysing and evaluating the design tools used, judging its relevance and value

Creative thinkers asking questions to extend their thinking about the programming language to be used.


Functional Skills – Level 2


ICT – Using ICT

Plan solutions to complex tasks by analysing the necessary stages

describing the stages of the software development life-cycle

Use appropriate software to meet the requirements of a complex data-handling task

designing a software solution

Evaluate the selection, use and effectiveness of ICT tools and facilities used to present information

reviewing the design against the original requirement.


Documents

Unit 18: Software Design - OneFilequals.onefile.co.uk/pdf/unit/EBIIT_018.pdf · Unit 18: Software Design Unit code: T/601/5110 ... P5 design a software solution to a business requirement