Data Flow Diagrams. Data and databases - Data Flow Diagrams. Introduction

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Data and databases - Data Flow Diagrams

Data Flow Diagrams

Introduction

This activity is about constructing Data Flow Diagrams (DFDs). The teacher or trainer introduces the ideas and notation used in DFDs and this is followed by the activity itself which has

two stages.

The first stage is a role play using a scenario based on a dental practice. Learners play the roles of patients (three), receptionist and dentist. They are given briefing notes to tell them who they are and roughly what they need to do. Others watch the role play and capture the entities, data flows, processes and data stores as the role play progresses. Learners record their findings on flip charts or white boards.

You could stop at this point and omit Stage 2 or move on to Stage 2 immediately or at a later date.

In Stage 2, after the role play, learners are divided into groups of three or four and given cards with entities, data stores, processes and data flow arrows from which they construct a DFD diagram for the dental practice system.

Aims

The aim of this session is to enable learners to understand how to construct DFDs and to understand the symbols used in the notation Structured Systems Analysis and Design Method (SSADM). It may be linked to projects that learners are undertaking or

are planning.

Learning objectives

At the end of this session learners will be able to: • capture data from a system dynamically

• recognise and use the symbols required to construct a Data Flow Diagram

• create a Data Flow Diagram for a given system.

Getting learners

to understand

the contruction

of Data Flow

Diagrams is the

aim of this

section

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Data and databases - Data Flow Diagrams

Resources

• Role play material (this needs to be printed, laminated and cut up before the session).

• Cards used to create a DFD of the dental practice (these need to be printed, laminated and cut up before the session) • Learner guidance notes.

• Flip charts or whiteboards and pens (not provided).

Preparation

The files which need to be printed and laminated can be found on the Teacher resources CD-ROM in your pack. They can be found on the CD-ROM under Learner activities resources for advanced learning examples.

For the files Patient record cardand Receipt, print and cut out the three cards. Print the files Dentist, New patient, Existing patientand

Receptionist.

For the file DFD cards, cut each page so that each symbol or box is separate. You may wish to enlarge the cards if they seem too small. Do the same for DFD blank cards. From the first two pages cut out the individual sets of lines of text as separate items for example:

patient record

On the next page cut out entries such as: reception

enter payment details

as single items. On the next page cut out each line of text as a separate item. For the rest of the file cut out everything as separate items

You will need a complete set of everything for each group in the session.

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Teacher and trainer guidance

Introduction

Before starting this activity learners should be familiar with the concept of DFDs and their use in documentation. They should be familiar with the symbols and understand the use of different levels of DFD.

Stage 1

1. Scenario

New patients are asked a series of questions (their name, address, GP’s name and surgery, any medication they are currently taking and any allergy details or general health concerns) when they join a dental practice. A receptionist writes these on to a Patient Record Card that is filed in a cabinet. The learner playing the role of new patient needs to understand that they should give this kind of detail to the receptionist.

Patients book appointments through the receptionist. The

appointments are logged in a ‘page a day diary’. Each morning the receptionist checks the diary. For each appointment that day the Patient Record Cards are taken from the filing cabinet and kept by the receptionist. When an existing patient arrives he/she is given their Patient Record Card to take into the dentist. The dentist sees each patient in turn and notes changes to the patient's health details or details of the treatment given during the appointment on the Patient Record Card.

After their appointment patients usually have to pay for the

consultation. The required fee for treatment is logged onto an Excel spreadsheet. The patient’s name, the treatment given and the amount paid is entered onto the spreadsheet. When payment is received, patients are given a paper receipt and the payment is recorded in the spreadsheet.

2. Introduce the activity

Select people to play the various roles - three printouts (two existing, one new), one receptionist, one dentist. Hand out the role play material and explain what each person has to do. The central role is the receptionist, so choose this learner carefully. Select

Data and databases - Data Flow Diagrams

Role play is used

to practise data

storage and

maintenance

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someone who will keep the role play going and be able to use their own initiative. Brief one of the learners that they are to play the role of a new patient registering with the dentist.

Allocate those not involved in the role play into groups of three and give each group a white board or a flip chart to write on. Tell the groups that their job is to capture the entities, processes, data stores and data flows during the role play.

Begin the role play and assist as necessary. The role play begins with one of the patients announcing their arrival to the

receptionist. You may find it useful to control the flow of patients through the system to make sure that the observers can record and understand the process.

3. Plenary

At the end of the role play, congratulate the players and turn to the observers. Ask the first group to briefly explain what they have recorded. Call for questions and comments. Ask subsequent groups to identify any differences and get them to explain why. Correct any misconceptions as you go through this process. Summarise the findings.

Stage 2 - Further practice

1. Form new groups of three or four, including those involved in

the role play. Hide the solutions on the boards/flip charts and hand out the materials to each group. Ask them to create a DFD for the dental practice system using the entities, data stores, data flows and processes provided. Give advice and assistance where required.

Stage 3 - Plenary

1. Summarise the stages required in the development of a DFD

for the dental surgery and ask the learners what they found difficult. Discuss how the learners could start to develop their own DFDs.

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Data and databases - Data Flow Diagrams

Learner guidance

This activity is about constructing Data Flow Diagrams (DFDs). The activity consists of two stages. The first stage is a role play of a scenario based on a dental practice. You might be asked to play the role of a patient, the receptionist or the dentist. You will be given briefing notes to tell you who they are and what you need to do. If you are not part of the role play you will be part of a small group whose job is to observe and capture the entities, data flows,

processes and data stores. Discuss issues with your group members and record your findings on flip charts or whiteboards.

For the second stage you will be assigned to a small group and be given cards with entities, data stores, processes and data flow arrows from which you are to construct a Data Flow Diagram for the dental practice system.

Learning objectives

This session aims to get you to understand how to construct DFDs and to understand the symbols used in one notation, Standard Systems Analysis and Design Method (SSADM).

At the end of this session you will be able to:

• recognise and use the symbols required to construct a Data Flow Diagram

• create a Data Flow Diagram for a given system.

Resources

• Role play material.

• Cards used to create a DFD of the dental practice. • Learner guidance notes.

• Flip charts or whiteboards and pens.

This two-stage

activity is

designed to help

you understand

and construct

Data Flow

Diagrams

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Stage 1 - Role play

1. If you have been chosen to play one of the roles (patient, receptionist or dentist) you will be given a card explaining your role. Do your best to put yourself in the role and enjoy taking part.

2. If you are not playing a role, you will be a member of a small group whose job it is to record what you see going on in the role play and to identify and write down the entities, processes, data stores and data flows as the role play proceeds. You should select one of the group to do the writing and record the

entities, processes, data stores and data flows on a flip chart or whiteboard. You will need to discuss what to write with the other members of the group.

3. At the end of the role play your group will be asked to briefly explain what you have recorded. You will need to select a member of your group to speak on your behalf.

Stage 2 - Creating a DFD

1. For this stage your teacher or trainer will form new groups of three or four. Your task, as a group, is to create a DFD for the dental practice system using cards with the given entities, data stores, data flows and processes. You will need to discuss how to do this with your fellow group members.

2. At the end of this stage, you will be asked what problems you met.

Data and databases - Data Flow Diagrams

Your task is to

construct a DFD

for a dental

practice using

cards with the

data flow

elements

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Role play information

Dentist

When a patient comes to you he will give you his Patient Record Card. You should pretend to give the patient some kind of treatment and at the end, pretend to mark his/her card with the treatment carried out and give it back to the patient who will take the card to the receptionist.

Receptionist

Current patients book appointments through the receptionist. The appointments are logged in a page a day diary. Each morning you check the dentist's appointment diary. For each appointment that day the Patient Record Cards are retrieved.

You will have record cards ready for when the patients arrive. When a patient with an appointment arrives, you give the patient his/her record card and send them into to see the dentist, When the patient comes out again, you take the card, tell the patient how much it costs, pretend to take some money and give the patient a receipt.

You repeat this for the next patient.

When a new patient arrives you ask a series of questions (as on the Patient Record Card) and pretend to fill in the details the patient gives you. You then pretend to make a booking for the patient and send him/her away.

Existing patient

You have booked an appointment and need to go to the receptionist and say who you are. You will be given your Patient Record Card to present to the dentist. When the treatment is over, you need to take your card back to the receptionist and pay for your treatment. You will be given a receipt.

New patient

New patients are asked a series of questions when they join a dental practice. You will be asked your name, address, GP's name and surgery, any medication you are currently taking and any allergy details or general health concerns. You should give these to the receptionist when you arrive.

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Date . . . .

Time

Patient diary

8:00

9:00

10:00

11:00

12:00

13:00

14:00

15:00

16:00

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Patient Record Card

Forename Surname

Address

GP Name GP Surgery

Allergies

General Health Concerns

Date Check up notes/patient's health Details of treatment

Patient Record Card

Forename Surname

Address

GP Name GP Surgery

Allergies

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Forename Surname

Address

GP Name GP Surgery

Allergies

Date Check up notes/patient's health Details of treatment

Patient Record Card

Forename Surname

Address

GP Name GP Surgery

Allergies

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Snowchester Dental Practice

Receipt

Name

Amount

Date

Snowchester Dental Practice

Receipt

Name

Amount

Date

Snowchester Dental Practice

Receipt

Name

Amount

Date

Snowchester Dental Practice

Receipt

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Patient

details

Patient

details

Preferred

dates

Preferred

dates

Appointment

details

Appointment

details

Today's

date

Today's

date

Today's

appointments

Today's

appointments

Patient

details

Patient

details

Treatment and

fee details

Treatment and

fee details

Fee

details

Fee

details

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Patient

treatment

Patient

treatment

Payment

Receipt

Treatment details

and payments

Treatment details

and payments

Patient

details

Patient

details

Patient

details

Patient

details

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Reception

Enter patient

details

Reception

Enter payment

details

Reception

Update patient

record

Reception

Book

appointment

Reception

Check daily

appointments

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Patient Record Card

Appointment diary

Payment spreadsheet

Patient Record Card

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Patient

details

Patient

details

Preferred

dates

Preferred

dates

Appointment

details

Appointment

details

Today's

date

Today's

date

Today's

appointments

Today's

appointments

Patient

details

Patient

details

Treatment and

fee details

Treatment and

fee details

Fee

details

Fee

details

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Patient

treatment

Patient

treatment

Payment

Receipt

Treatment details

and payment

Treatment details

and payment

Today's

appointments

Today's

appointments

Patient

details

Patient

details

Patient

details

Patient

details

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Receptionist

Patient

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Data and databases - Database dominoes

Database dominoes

Introduction

This domino activity is designed to be used as a revision tool to reinforce learners’ understanding of specialist terminology and to encourage learners to think about the connections between different concepts and terms.

There are four domino sets in the pack for use in the teaching of four topics:

• Databases (Data and databases) • Communication systems (Networks) • Malpractice and crime (Social implications) • ICT Capabilities (Social implications).

The idea is extremely flexible and can be used to teach other topics This activity may form one activity within a longer session.

A blank set is included for you to adapt.

Aims

The aim of this session is to enable learners to understand the meaning of technical terms relating to databases. It is also intended to help learners remember terms and definitions.

Learning objectives

At the end of this session learners will be able to: • Recall the meaning of key terms.

• Understand the connection between terms. • Use terms in the correct context.

Resources

Dominoes (on cards) - one set for each group.

The sheets of dominoes which are included in this booklet and on the Teacher resources CD-ROM, are more durable when laminated, then guillotined.

The words are arranged in pairs per domino and should be cut out in pairs. The two words on one domino are unlikely to have any connection with each other.

Signpost

The components for this activity are in your pack.

Files for teacher and trainer guidance, learner guidance and the dominoes are on the Teacher resources CD-ROM.

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Teacher and trainer guidance

1. Divide learners into groups of three or four. Each group will need one set of 18 dominoes.

2. Each group is asked to spread the dominoes out, keeping them face down.

3. Each member of the group takes a domino in turn until all the dominoes have been taken. Groups of three will get six

dominoes each and groups of four will get four dominoes each. 4. One learner starts and puts down a domino face up. They then

explain/define the two terms on their domino. Other members of the group can challenge the explanation. If the challenge is successful the learner takes their domino back and the next learner puts down a domino and explains the two terms. You may need to act as referee!

5. Once an explanation/definition has been successful, the domino is left face up on the table. The next learner then selects a domino which relates in some way to one of the terms on the last domino laid down.

6. This learner has to define the terms on their new domino and also explain what the link is to the domino they have laid it against.

7. Again, other members of the group can challenge the definitions and/or link and if the challenge is successful the domino has to be withdrawn. The next player in turn puts one of their dominoes down and repeats the process.

8. If a learner realises that they cannot make a link with any of their dominoes they can pass. It is anticipated that passes will occur.

9. The first person with no dominoes left is the winner of that round.

10. The dominoes are placed face down in the middle, shuffled and the game can restart as the sequence of dominoes and

therefore the relationships will be different each time.

11. At the end of the activity the dominoes should be collected by each group and clipped back together.

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Learner guidance

1. When you receive the set of dominoes, spread them out, keeping them face down.

2. Each player takes a domino. Repeat this until all the dominoes have been taken. (Groups of three will get six dominoes each and groups of four will get four dominoes each).

3. Decide who will go first. This player puts down a domino face up and explains/defines the two terms on their domino. Other members of the group can challenge the explanation. If the challenge is successful the player takes back their domino and the next player puts down a domino and explains the two terms. Your teacher or trainer will act as referee!

4. Once an explanation/definition has been successful, the

domino is left face up on the table. The next player then selects a domino which relates in some way to one of the terms on the last domino laid down.

5. This player has to both define the terms on their new domino and explain what the link is to the domino they have laid it against.

6. Again other members of the group can challenge the definitions and/or link and if the challenge is successful the domino has to be withdrawn. The next player in turn puts one of their dominoes down and repeats the process.

7. If a player realises that they cannot make a link with any of their dominoes they can pass.

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Data and databases - Validation checks - matching exercise

Validation checks - matching exercise

Introduction

Two activities to reinforce learners' understanding of validation checks including:

matching definitions and identifying validity checks for particular circumstances.

This activity can be used as part of a longer session.

Aim

The aim of this activity is to enable learners to understand the different methods that can be used to validate data and how they can be applied.

Learning objectives

At the end of this session learners will be able to: • define methods of checking validity

• use appropriate methods for attributes in an online product catalogue table

• use appropriate methods for attributes for updating a membership table.

Resources

Cards with validation definition and example - one set for each pair. Cards with validation term - one set for each pair.

Worksheet - online product catalogue. Worksheet -membership update.

Copies of the resources to download and print are on the Teacher resources CD-ROM.

The aim of this

activity is to

enable learners

to understand

the different

methods that can

be used to

validate data and

how they can be

applied

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Teacher and trainer guidance

1. Divide the learners into pairs and give each pair two sets of cards.

a. definition of validation checks. b. terms used for validation checks.

2. Using the cards, ask the learners to work together to match the validation definition card with the correct validation term card. 3. When the matching activity is finished, learners, working in

pairs, complete the online product catalogue worksheet. 4. When the worksheet has been completed ask each pair to

share their answers using group discussion or by asking pairs to review another pair’s answers.

5. Summarise the activities and give feedback on their solution.

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Data and databases - Validation checks - matching exercise

Learner guidance

1. Your teacher or trainer will ask you to work in groups of two. 2. One person places a validation definition card on the table. 3. Work through the terms cards together until you find the term

which matches the definition. Make sure that you both agree with the answer chosen.

4. When you have finished the matching exercise move on to the worksheet which uses examples from an online shopping catalogue.

5. Complete the worksheet following the instructions, but make sure that you both agree with your choice of answer.

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Validation checks - matching exercise

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Validation checks - matching exercise

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T

ask

Y ou ar e designing the da tabase f or an online pr oduc t ca talogue wher e each en tr y is to ha v e the a ttributes sho wn belo w : pr oduc t co

de (six digit number),

ca tegor y c o de (G-games ,B-books ,E- equipmen t), description, number in stock, retail pric e ,buy-in pric e . T he pr ogr am t o cr eat e the original st

ock table will ha

v e v a rious v alidation checks in ac tion. Suggest (with a cr oss in the bo x) which v alidation

check(s) should be used

.

P

roduc

t

co

d

e

C

a

tegor

y

co

d

e

Description

Number

in stock

Retail

pric

e

Buy-in

pric

e

L

ength

F

o

rma

t

R

ange

V

e

rifica

tion

P

resenc

e

U

nique

L

o

okup

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Lookup check

Presence check

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Range check

Format check

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Storage and software - matching exercise

Introduction

This activity is about PC storage devices and software and their use in typical applications. There are two tasks that may be used with individual learners or small groups.

Stage 1 is about storage devices and requires learners to match specific storage devices to typical user tasks.

Stage 2 is about PC software packages and requires learners to match specific software packages to typical user tasks.

Aim

The aim of this activity is to enable learners to understand the tasks that PC storage devices perform.

Learning objectives

At the end of this session learners will be able to:

• Understand the typical tasks performed by storage devices. • Remember and describe the tasks of PC storage devices.

Resources

• A copy of learner guidance for each learner. • Flip chart or whiteboard.

Hardware and software - Storage and software uses - matching exercise

This activity is

about PC storage

devices and

software and

their use in

typical

applications

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Stage 1

1. Divide the learners into groups and identify a note-taker for each group who will record the group's answers.

2. Provide each learner with a copy of the learner guidance for Stage 1.

3. Introduce the activity and ask the learners to complete the worksheet working in groups.

4. When the groups have completed the activities, encourage them to share their answers as a group or by asking groups to review another group’s answers.

Stage 2

1. A similar activity is provided which covers the use of software applications. The activity can be used in a similar way to the activity on storage devices. It could be used as an alternative exercise for a different group of learners.

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Learner guidance for Stage 1 activity

Storage devices matching exercise

1. Below, to the left, is a set of common storage devices labelled A to H. To the right is a list of tasks a computer user may be involved in.

2. For each of the tasks, select which of the storage devices you think would be the most appropriate - be careful as not all of them are so obvious. Write the appropriate letter in the ‘Chosen device’ column.

3. When you have done that, state the main feature of your selected device that made you think it was best for the task.

Devices A Memory card B CD-ROM C Floppy disk D DAT tape E CD-R F Hard disk G DVD H USB storage device Tasks Chosen device Feature 1 Archiving 300Mb of data

2 Holding programs frequently

used on the computer

3 Distributing a 500Mb sales

catalogue to travelling sales staff

4 Storing 100Mb of high resolution

digital photographs

5 Transferring a 100k file between

2 standalone computers

6 Backing up a 80Gb network server

disk

7 Storing 200Mb of web pages

accessed over the internet

8 Transferring a 50Mb file between

2 standalone computers

9

Backing up 3Gb of programs and data held on a standalone

computer at home

10 Storing 3000 music tracks on a

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Hardware and software - Storage and software uses - matching exercise

Learner guidance for Stage 2 activity

Software matching exercise

1. Below and to the left is a list of common software packages labelled A to G. To the right is a list of tasks a computer user may be involved with.

2. For each of the tasks, select which of the software packages you think would be most appropriate - be careful, as not all of them are obvious. Write the appropriate letter in the 'Software to use' column.

3. When you have done this, state the main feature of your selected software package that made you think it was best for the task

Devices A Word processor B Spreadsheet C Presentation graphics D Desktop publishing E Database F Computer aided design G Email Tasks Software to use Feature 1 Storing customer records

2 Designing a new product

3 Creating a glossy catalogue

of products

4 Preparing a sales record for

the Board of Directors

5 Creating a supplier order

6 Producing a letter

7 Deciding on a new kitchen layout

8 Keeping a list of contacts

9 Producing invoices for customers

10 Sending an urgent memo to Australia

11 Delivering a task to prospective

students

12 Comparing seat occupancy at the

various screens at a cinema

13 Maintaining a diary of appointments

14 Preparing an estimate for

double glazing

15

Delivering a proposal for taking students on an Alpine adventure holiday

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Fetch-execute cycle

Introduction

This activity encourages learners to simulate the operation of the fetch-execute cycle. It uses a board and card based activity to help learners understand the basic principles of the process.

Aim

To enable learners to understand how data flows within the central processing unit (CPU) as instructions are executed.

Learning objectives

At the end of this session learners will be able to:

• simulate the actions of the CPU in fetching and executing instructions

• describe the role the various CPU registers play.

Resources

• A board and cards which need to be printed using a colour printer, laminated and cut up to create the playing board and the set of instruction and data cards plus a set of values for the program counter.

• Photocopiable resources are in this booklet. Files can also be downloaded from the Teacher resources CD-ROM under Learner activities, Resources for advanced learning examples. • Each group will need a board and a set of cards.

• Teacher and trainer guidance.

• Four learner guidance sheets, a different one for each of the roles (PC, ALU, instructions and data).

• PowerPoint presentation stored on the Teacher resources CD-ROM.

Hardware and software - Fetch-execute cycle

This activity

enables learners

to understand

how data flows

within the central

processing unit

(CPU) as

instructions

are executed

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Stage 1 - preparation

1. Organise the learners into groups of four.

2. The playing board consists of four pages that are set up in a square on the table. You will need as many copies as there are groups in the class.

3. The Learner guidance sheets contain information about the program file, PC file and data file. Each learner will need a copy of the guidance.

4. Teacher and trainers are strongly advised to work through the activity to prepare for the session.

Stage 2 - Introducing the activity

1. Introduce learners to the ideas behind the fetch-execute cycle. Explain the various registers involved in this process. Explain the task and that this is a very much simplified simulation of what is involved. Explain that they are going to execute a program. Some or all of the slides of the PowerPoint presentation can be used for this part of the session. 2. Break the learners into groups of four and assign the

following roles: program counter arithmetic-logic unit instructions

data

If they do not divide exactly into groups of four, create some groups of three and assign the roles of instructions and data to one person.

3. Give the person with the program counter role the yellow cards with the numbers 100, 101, 102 and 103.

4. Give the person with the arithmetic-logic role the red card with the number 75.

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5. Give the person with the instructions role two copies of blue cards with GET 400, ADD 401, STORE 402, STOP.

6. Give the person with the data role two copies of red cards with the numbers 46 and 29.

7. Set out the playing boards.

8. Give each person the learner guidance sheet that is

appropriate to their role and ask them to execute the program. 9. During the activity make sure that the activity is progressing

smoothly and be ready to advise if necessary.

10. A summary of the program is included on the next page.

Plenary

At the end of the session summarise the task. Ask learners questions about their experiences and what they found difficult. A follow up activity might involve them explaining the role of the memory buffer register and/or drawing a diagram showing the data flows between the various registers.

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Hardware and software - Fetch-execute cycle

The program

A summary of the program learners are going to execute are given below.

Sequence of events

Address Contents 100 GET 400 101 ADD 401 102 STORE 402 103 STOP 400 46 401 29 402 Initial state PC=100 PC IR Acc 400 401 402 100 GET 400 46 46 29 0 101 ADD 401 75 46 29 0 102 STORE 402 75 46 29 75 103 STOP 75 46 29 75

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Learner guidance for the fetch-execute cycle

Arithmetic-logic unit player (ALU)

The task of your group is to execute a program based on the way a CPU carries out the instruction cycle. The program you are going to execute is given below. Use the flow chart on the table showing the fetch-execute cycle to guide your actions. When it comes to that part of the cycle which is labelled decode the instruction,all group members should discuss what this involves for the instruction currently in the instruction register. When you are all agreed, you should carry out the instruction.

Your role is to execute the instruction in the instruction register, which may involve asking for data to be moved between memory and CPU registers. When you need to change the value in a register or a memory location, just put the new value on top of any cards in there from earlier in the program. When you have finished tell the person playing the role of the program counter to start the next cycle. You will be given one data (red) card which you will need to carry out the role of ALU.

The activity comes to an end when you reach the STOP instruction.

Program Add the contents of location 400 to the contents of

location 401 and store in location 402

Address Contents 100 GET 400 101 ADD 401 102 STORE 402 103 STOP 400 46 401 29 402 Initial state PC=100

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Learner guidance for the fetch-execute cycle

Data player

The task of your group is to execute a program based on the way a CPU carries out the instruction cycle. The program you are going to execute is given below. Use the flow chart on the table showing the fetch-execute cycle to guide your actions. When it comes to that part of the cycle which is labelled decode the instruction,all group members should discuss what this involves for the instruction currently in the instruction register. When you are all agreed, the person playing the role of the arithmetic-logic unit should carry out the instruction.

You will be given a number of copies of the red data cards which are going to be manipulated by the program. Your first task is to put the data into the right locations in memory; place as many copies of each data value as you have in the right location, one on top of the other. As the activity progresses you will need to

respond to requests from the arithmetic-logic unit to give a copy of an item of data (don't forget to ensure that value stays in the location unless it is overwritten) or to overwrite data in your part of memory.

Program Add the contents of location 400 to the contents of

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Learner guidance for the fetch-execute cycle

Instructions player

You will be given two copies of a number of blue cards

representing each instruction in the program. Your first task is to put the instructions of the program into the right locations in memory; place two copies of each instruction in the right memory location, one on top of the other. As the activity progresses you will need to respond to requests from the person playing the role of program counter to give a copy of an instruction in your part of memory.

Program Add the contents of location 400 to the contents of

Initial state PC=100

Hardware and software - Fetch-execute cycle

Address Contents 100 GET 400 101 ADD 401 102 STORE 402 103 STOP 400 46 401 29 402

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Learner guidance for the fetch-execute cycle

Program counter player

You will be given a number of yellow cards which represent the value of the program counter. Sort them into order and start by placing 100 in the PC register on the playing board and wait for the others to be ready to play. Your task is to start an instruction cycle by asking the person playing the role of instructions to give you the instruction located in the memory address pointed to by the PC. When you get the instruction, place it in the instruction register and update the value in the program counter. Put any new

program counter values on top of the ones already in there.

Program Add the contents of location 400 to the contents of

location 401 and store in location 402.

(46)

Instruction set

GET n

copy contents

of location n

to accumulator

register

STORE n

copy contents

of accumulator

register to

location n

ADD n

add the contents

of location n to

the accumulator

register

STOP

stop the program

Fetch instruction

pointed to by program counter and

place in intruction register

Add one to the program counter

Decode instruction

Execute instruction

(47)

Instructions

100

101

102

(48)

Data

400

401

(49)

CPU registers

PC

IR

(50)

46

29

75

Data

(51)

100

101

102

103

(52)

GET 400

STORE 402

STOP

GET 400

ADD 401

STORE 402

STOP

Program

(53)

Packet switching

Introduction

This activity simulates packet switching by breaking messages into packets and simulating sending them across a network.

The session starts with the teacher or trainer sending two

messages by feeding out packet cards to the front of the class and asking learners to pass them on to somebody else until the packet eventually reaches the recipient.

The exercise can be made as simple or sophisticated as you want. The idea is to demonstrate how a long and complex transmission can be split up into small packets, sent via various intermediaries and checked to see if it has been received correctly. You can decide on the level of detail you want to go into with IP addresses, error messaging, and “losses”. You could relate it to routers or other aspects of networking.

Learners being learners, they may treat it as a bit of fun and try to make it not work by sending words all over the room. The truth is, though, the messages will get through and this imitates the operation of the internet. It also helps to explain how certain components of web pages take longer to arrive then others and learners can directly relate this to their own experiences.

Aim

To enable learners to understand how messages are broken into packets and transmitted across a network.

Learning objectives

At the end of this session learners will be able to: • describe how messages are broken into packets

• simulate the way packets are passed around a network • describe how lost packets are dealt with.

Networks - Packet switching

The idea is to

demonstrate

how long

and complex

transmissions can

be split up into

small packets

(54)

Resources

• Photocopiable versions of the resources are in this booklet. You can also download and print them from the Teacher resources CD-ROM.

• One set of packet cards for the message to A, which needs to be printed twice.

• One set of packet cards for the message to B. • Two NAK card and two ACK cards.

(55)

Teacher and trainer guidance

Stage 1 - Introducing the activity

1. Introduce the learners to the ideas behind packet switching. 2. Select two learners at the back of the room and tell them they

are to be the initial receivers of the messages, one called A the other B. A's message sequence has seven items; B's sequence has nine. Give them each a record sheet with their name on them and both an ACK and a NAK packet card. Explain to these learners that as they receive a package addressed to them, they should record its arrival on their record sheet indicating the sequence they received it in. Make sure the class knows who is playing A and who is playing B.

Stage 2 - The activity in action

1. Start giving the cards to learners at the front, make sure that the two messages are mixed up, but hold back one card from one of the messages to A without telling the class what you are doing (and hold back the duplicate message cards to A). Explain that the class is acting as nodes/routers on the internet on the path to the recipients of the messages.

2. Instruct the learners to pass any card they receive to any other learner (except the one who gave them the card) as long as the cards eventually arrive at the learners named in the “Send to” box.

3. As each recipient (A or B) receives a message card with their name on it, they record the word which forms part of the message on the record sheet in the appropriate place, together with a sequence number showing the order in which the message card arrived.

4. Once a recipient (A or B) receives the entire message, they send an ACK message to the sender. Since one of the recipients (A) will be missing a card when there are no more packets circulating, they will need to send a NAK package.

5. When you receive the NAK card from A, send the duplicate message (the correct one this time). Once the second ACK packet gets back to you the activity ends.

(56)

Stage 3 - Plenary

1. At the end of the session summarise what learners have done. Ask questions about their experiences and discuss what they found difficult.

2. Follow up material might involve showing the example on the next page to demonstrate how messages are routed.

(57)

C:\Documents and Settings\walter>tracert www.jcc.ac.uk

Tracing route to www.jcc.ac.uk [80.87.131.206] over a maximum of 30 hops: Trace complete. 1 11 ms 11 ms 11 ms 217.47.203.122 2 11 ms 11 ms 11 ms 217.47.249.161 3 12 ms 11 ms 10 ms 217.41.172.13 4 13 ms 12 ms 12 ms 217.41.172.126 5 12 ms 11 ms 11 ms 217.41.172.54 6 11 ms 11 ms 11 ms 217.32.85.178 7 12 ms 11 ms 11 ms core2 pos53.birmingham.ukcore.bt.net [195.99.120.77] 8 13 ms 13 ms 12 ms core2-pos15-1.reading.ukcore.bt.net [194.74.16.234] 9 17 ms 15 ms 15 ms core2-pos15-2.ilford.ukcore.bt.net [194.74.16.133] 10 16 ms 15 ms 15 ms 194.74.65.198 11 16 ms 16 ms 18 ms 195.66.224.189 12 17 ms 16 ms 16 ms Positive_Internet_Company.demarc.cogentco.com [130.117.21.106] 13 19 ms 17 ms 17 ms atlantis.positive-internet.com [80.87.128.4] 14 17 ms 17 ms 18 ms pod-206.dolphin-server.co.uk [80.87.131.206]

(58)

Packet number

Message word

Arrival sequence

Packet 1 of 7

Packet 2 of 7

Packet 3 of 7

Packet 4 of 7

Packet 5 of 7

Packet 6 of 7

Packet 7 of 7

(59)

B's message sheet

Packet number

Message word

Arrival sequence

Packet 1 of 9

Packet 2 of 9

Packet 3 of 9

Packet 4 of 9

Packet 5 of 9

Packet 6 of 9

Packet 7 of 9

Packet 8 of 9

Packet 9 of 9

(60)

The

Packet 1 of 7

SEND TO A

SENDER’S

ADDRESS

internet

Packet 2 of 7

SEND TO A

SENDER’S

ADDRESS

(61)

is

Packet 3 of 7

SEND TO A

SENDER’S

ADDRESS

a

Packet 4 of 7

SEND TO A

SENDER’S

ADDRESS

(62)

collection

Packet 5 of 7

SEND TO A

SENDER’S

ADDRESS

of

Packet 6 of 7

SEND TO A

SENDER’S

ADDRESS

(63)

networks

Packet 7 of 7

SEND TO A

SENDER’S

ADDRESS

(64)

The

Packet 1 of 9

SEND TO B

SENDER’S

ADDRESS

world

Packet 2 of 9

SEND TO B

SENDER’S

ADDRESS

(65)

wide

Packet 3 of 9

SEND TO B

SENDER’S

ADDRESS

web

Packet 4 of 9

SEND TO B

SENDER’S

ADDRESS

(66)

is

Packet 5 of 9

SEND TO B

SENDER’S

ADDRESS

a

Packet 6 of 9

SEND TO B

SENDER’S

ADDRESS

(67)

collection

Packet 7 of 9

SEND TO B

SENDER’S

ADDRESS

of

Packet 8 of 9

SEND TO B

SENDER’S

ADDRESS

(68)

pages

Packet 9 of 9

SEND TO B

SENDER’S

ADDRESS

(69)

NAK

Packet 1 of 1

SEND TO:

SENDER’S

ADDRESS

NAK

Packet 1 of 1

SEND TO:

SENDER’S

ADDRESS

(70)

ACK

Packet 1 of 1

SEND TO:

SENDER’S

ADDRESS

ACK

Packet 1 of 1

SEND TO:

SENDER’S

ADDRESS

(71)

Networks - Communication system dominoes

Communication system dominoes

Introduction

Aims

Learning objectives

Resources

Signpost

The components for this activity are in your pack.

(72)

Teacher and trainer guidance

(73)

Learner guidance

(74)

Networks - Communication system dominoes

Communication system dominoes

Introduction

Aims

Learning objectives

Resources

Signpost

The components for this activity are in your pack.

(75)

Teacher and trainer guidance

(76)

Learner guidance

(77)

(78)

(79)

Algorithms - Is it a triangle?

Introduction

This activity is about solving problems, using logic and generating algorithms. Learners work in groups of three or four, with one note taker in each group, and discuss the factors which determine whether or not three lengths can form a triangle. Making notes on their observations for each envelope helps the groups decide on a logical rule that will decide whether or not a triangle can be formed. The groups are then asked to generate suitable

pseudo code.

Aims

The activity aims to develop problem solving skills, application of logic and give an understanding of pseudo code.

Learning objectives

At the end of this activity learners will be able to:

• understand that successful programs are developed using logical steps.

• understand the importance of pseudo code in the program design process.

Resources

Each group will need six envelopes with contents as indicated on the following page. Thin dowel is best for the rods. Straws could be used but have the drawback of being rather bendy and flimsy. To ensure the sets of rods are easy to check it is best if the envelopes are a colour that matches rods marked with a similar colour. The rod colour can be indicated with a band of coloured tape around each. Learners will need a set of guidance notes.

Programming - Algorithms - Is it a triangle?

This activity is

about solving

problems,

using logic

and generating

algorithms

(80)

A Solution

Rule:

If the length of each rod is less than the total length of the other two then you can form a triangle.

Pseudo code: IF

Rod A < Rod B + Rod C

AND Rod B < Rod A + Rod C AND Rod C < Rod A + Rod B THEN a triangle can be formed ELSE unable to form a triangle

Programming - Algorithms - Is it a triangle?

Envelope Rod length/cm

Colour

Comments

1

A 16 B 20 C 10

no colour 3 rods which can form a triangle 2 yellow A 14 B 15 C 16

yellow 3 rods which can form a triangle 3 red A 12 B 5 C 10

red 3 rods which can form a triangle 4 blue A 5 B 8 C 15

blue 3 rods which do not form a triangle 5 black A 10 B 8 black 2 rods and a

photocopy of a 12in(30cm) ruler

6

A 20 B 15 C 10

no colour

3 rods stuck, parallel with each other, to a piece of card and covered with cling film so they

cannot be moved. A photocopy of a 12in(30cm) ruler.

(81)

Teacher and trainer guidance

Stage 1 - Preparing the session

1. Create a set of resources as described in the resources section.

2. Prepare the learners for the activity by introducing the idea of pseudo code. You might like to use the example of the ‘square’ problem in the Learner guidance.

3. Provide each learner with a set of Learner guidance. 4. Organise the learners into groups of four.

Stage 2 - Introducing the activities

1. Make sure that the learners understand the purpose of the activity and that they understand the instructions.

2. Allow the learners to work through the activity, but be prepared to advise where necessary.

Stage 3 - Plenary

1. Start a discussion with your learners about the activity, highlighting what they found difficult and what they have discovered.

2. Feedback is important in this activity. This can be done in several ways. You might like to finish the session by providing an answer or you might like to give feedback to each group in turn.

3. A suitable extension activity would be to write pseudo code for a right-angled triangle using Pythagoras’ theorem.

(82)

Programming - Algorithms - Is it a triangle?

Learner guidance

This activity is about constructing an algorithm to decide whether three lengths can fit together to form a triangle.

Resources

Each group will have six envelopes numbered 1 to 6. Each envelope will contain a number of items. Envelopes 1, 2, 3 and 4 have three rods. Envelope 5 has two rods and a ruler. Envelope 6 has three rods attached to a card, and a ruler.

• You must work with the contents of only one envelope

at a time.

• You are not allowed to use items from one envelope to help

complete another task.

Instructions

1. Open envelopes 1 to 4 in turn. For each envelope your group must decide if it is possible to construct a triangle from the three rods (A, B, C). Use the table on page 3 to record your results. While doing each task, take note of any relationship you notice between the lengths of the rods. (You can refer to the rod lengths as A, B and C).

2. Open envelope 5 (two rods and a ruler) and decide what length of rod could complete the formation of a triangle. Complete the table below relating to envelope 5. Tell your teacher or trainer the length you have chosen. Your teacher or trainer will ask your group how you decided on the length and what the maximum length is that you could use.

(83)

Programming - Algorithms - Is it a triangle?

Note the maximum length that you could use. Take note again of any relationship between the lengths.

By this time you should have noticed a relationship between lengths. If not, look at envelopes 3 and 4 again. Use this relationship to make a rule which you can use to prove your answers to 1 and 2.

3. Open envelope 6 (three rods fixed to a card, and a ruler). Decide if a triangle could be constructed. Complete the table and indicate that you have completed the task. You will be required to explain how you decided.

4. An example rule for stating if you can make a square is: “If all four sides are the same length then you can form a square”.

You should now have a similar rule, which when applied, decides if three lengths can make a triangle or not. Convert your rule into PSEUDO CODE. Later you will be required to convert this to a working program.

For instance the pseudo code for a square is: IF

side A = side B AND side B = side C AND side C = side D

THEN a square can be formed ELSE

(84)

S

ession Plan

Dur a tion: 1 hour 30 mins A

im/s of the session:

to

dev

elop pr

oblem solving sk

ills

,application of logic and giv

e an understanding of pseudo c o de . Objec tiv e: to

devise a set of instruc

tions which will alwa

y s decide whether an y thr ee lengths can f o rm a triangle .

10 mins

50 mins

20 mins

Subjec

t

Recap

.What is an

algorithm and pseudo c

o

de?

What is a squar

e?

What is a triangle? Feedback Algorithm and pseudo co

de t

o

find if f

our

sides can mak

e a

squar

e

Algorithm and pseudo co

de t

o

find if thr

ee

sides can mak

e

a triangle Check

ing solutions

Understanding of the terms algorithm and pseudo c

o

de

Exposition and questions and answ

ers L earners in gr oups of thr ee or four . Facilitat e ac tivit y t o see if it ems pr o vided in each en v

elope can mak

e a triangle , and r equest additional it ems . V

erbal and writt

en solutions

fr

om gr

oups

Exposition and student questions

Responses Requesting a suitable length t

o complet e a triangle P seudo c o de t o solv e pr oblem Obser v e r esponses Responses Classr oom pr ojec tor & whit eboar d En v e lopes co ntaining pr e-cut r o ds and rulers . En v e lopes co ntaining pr e-cut r o ds and rulers . Classr oom pr ojec tor & whit eboar d

L

earning

outc

omes

T

eaching and

learning ac

tivities

V

e

rifica

tion

L

o

okup

(85)

Is it a triangle?

Table for answers

Envelope

Triangle can be formed?

yes no If 'no', why not Observations

1

2

3

4

Envelope

Triangle can be formed?

yes no How did you know?

1

Envelope Length of rod How did you know?

4

(86)

(87)

Searching and sorting - Numberline

Introduction

These resources can be used in various ways to enable learners, working in pairs, to understand and practise searching and sorting techniques and ultimately to be able to devise the appropriate algorithm. For instance they have been used for:

• binary search • binary chop • bubble sort

• stack and queue operation • arrays.

There is one set of data cards in this pack (animals) but the scope of data can be chosen by the teacher or trainer.

Learning objectives

At the end of the session learners will be able to:

• Work in pairs and discuss solutions using the language of the technique/s.

• Practise search, sort, stack operation, queues, array techniques. • Formulate appropriate algorithms.

• Document the algorithms.

• Understand the differences between different techniques.

Resources

The ruler, which should be fixed to the table.

A set of 15 cards - one set provided with names of animals. A blank set of 15 cards to make other sets of data.

Programming - Searching and sorting - Numberline

Signpost

The components for this activity are in your pack. There are also files for teacher