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

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1 Data and databases - Data Flow Diagrams Data Flow Diagrams Getting learners to understand the contruction of Data Flow Diagrams is the aim of this section 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.

2 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 card and Receipt, print and cut out the three cards. Print the files Dentist, New patient, Existing patient and 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.

3 Data and databases - Data Flow Diagrams 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. Role play is used to practise data storage and maintenance 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

4 Data and databases - Data Flow Diagrams 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.

5 Data and databases - Data Flow Diagrams Learner guidance This two-stage activity is designed to help you understand and construct Data Flow Diagrams 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.

6 Data and databases - Data Flow Diagrams Your task is to construct a DFD for a dental practice using cards with the data flow elements 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.

7 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.

8 Page a day diary Date Time Patient diary 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00

9 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 General Health Concerns Date Check up notes/patient's health Details of treatment

10 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 General Health Concerns Date Check up notes/patient's health Details of treatment

11 Snowchester Dental Practice Receipt Snowchester Dental Practice Receipt Name Name Amount Amount Date Date Snowchester Dental Practice Receipt Snowchester Dental Practice Receipt Name Amount Date

12 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

13 Patient treatment Patient treatment Payment Payment Receipt Receipt Treatment details and payments Treatment details and payments Patient details Patient details Patient details Patient details

14 Reception Reception Enter patient details Book appointment Reception Reception Enter payment details Check daily appointments Reception Update patient record

15 Patient Record Card Patient Record Card Appointment diary Appointment diary Payment spreadsheet Payment spreadsheet Patient Record Card Patient Record Card

16 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

17 Patient treatment Patient treatment Payment Payment Receipt Receipt Treatment details and payment Treatment details and payment Today's appointments Today's appointments Patient details Patient details Patient details Patient details

18 Receptionist Receptionist Receptionist Receptionist Patient Patient Patient Patient Dentist Dentist

19 Data and databases - Database dominoes Database dominoes 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. 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.

20 Data and databases - Database dominoes 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.

21 Data and databases - Database dominoes 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. 8. The first person with no dominoes left is the winner of that round.

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24 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. 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 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.

25 Data and databases - Validation checks - matching exercise 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.

26 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.

27 Validation checks - matching exercise Definition cards

28 Validation checks - matching exercise Definition cards

29 Validation checks - matching exercise Team cards

30 Task You are designing the database for an online product catalogue where each entry is to have the attributes shown below: product code (six digit number), category code (G-games, B-books, E- equipment), description, number in stock, retail price, buy-in price. The program to create the original stock table will have various validation checks in action. Suggest (with a cross in the box) which validation check(s) should be used. Length Format Range Verification Presence Unique Lookup Product code Category code Description Number in stock Retail price Buy-in price

31 Lookup check Presence check Verification check

32 Range check Format check Uniqueness check

33 Length check

34 Hardware and software - Storage and software uses - matching exercise Storage and software - matching exercise This activity is about PC storage devices and software and their use in typical applications 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.

35 Hardware and software - Storage and software uses - matching exercise Teacher and trainer guidance 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 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.

36 Hardware and software - Storage and software uses - matching exercise 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 Tasks Chosen device Feature A Memory card 1 Archiving 300Mb of data B CD-ROM 2 Holding programs frequently used on the computer C Floppy disk 3 Distributing a 500Mb sales catalogue to travelling sales staff D DAT tape 4 Storing 100Mb of high resolution digital photographs E CD-R 5 Transferring a 100k file between 2 standalone computers F Hard disk 6 Backing up a 80Gb network server disk G DVD 7 Storing 200Mb of web pages accessed over the internet H USB storage device 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 portable music player

37 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 Tasks Software to use Feature A Word processor 1 Storing customer records 2 Designing a new product B C D E Spreadsheet Presentation graphics Desktop publishing Database 3 4 Creating a glossy catalogue of products 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 F Computer aided design 8 Keeping a list of contacts 9 Producing invoices for customers G 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

38 Hardware and software - Fetch-execute cycle Fetch-execute cycle This activity enables learners to understand how data flows within the central processing unit (CPU) as instructions are executed 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.

39 Hardware and software - Fetch-execute cycle Teacher and trainer guidance 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 Give the person with the arithmetic-logic role the red card with the number 75.

40 Hardware and software - Fetch-execute cycle 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 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.

41 Hardware and software - Fetch-execute cycle The program A summary of the program learners are going to execute are given below. Address Contents 100 GET ADD STORE STOP Initial state PC=100 Sequence of events PC IR Acc GET ADD STORE STOP

42 Hardware and software - Fetch-execute cycle 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 ADD STORE STOP Initial state PC=100

43 Hardware and software - Fetch-execute cycle 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. 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 ADD STORE STOP Initial state PC=100

44 Hardware and software - Fetch-execute cycle Learner guidance for the fetch-execute cycle Instructions 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 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. 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 ADD STORE STOP Initial state PC=100

45 Hardware and software - Fetch-execute cycle Learner guidance for the fetch-execute cycle Program counter 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 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. 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 ADD STORE STOP Initial state PC=100

46 Fetch instruction pointed to by program counter and place in intruction register Add one to the program counter Decode instruction 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 Execute instruction

47 Instructions

48 Data

49 CPU registers PC IR Acc

50 Data

51 PC

52 Program GET 400 STORE 402 STOP GET 400 ADD 401 STORE 402 STOP

53 Networks - Packet switching Packet switching The idea is to demonstrate how long and complex transmissions can be split up into small packets 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.

54 Networks - Packet switching 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. A's record sheet and B's message sheet.

55 Networks - Packet switching 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 Networks - Packet switching 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 Networks - Packet switching C:\Documents and Settings\walter>tracert Tracing route to [ ] over a maximum of 30 hops: 1 11 ms 11 ms 11 ms ms 11 ms 11 ms ms 11 ms 10 ms ms 12 ms 12 ms ms 11 ms 11 ms ms 11 ms 11 ms ms 11 ms 11 ms core2 pos53.birmingham.ukcore.bt.net [ ] 13 ms 13 ms 12 ms core2-pos15-1.reading.ukcore.bt.net [ ] 17 ms 15 ms 15 ms core2-pos15-2.ilford.ukcore.bt.net [ ] ms 15 ms 15 ms ms 16 ms 18 ms ms 16 ms 16 ms Positive_Internet_Company.demarc.cogentco.com [ ] 19 ms 17 ms 17 ms atlantis.positive-internet.com [ ] 17 ms 17 ms 18 ms pod-206.dolphin-server.co.uk [ ] Trace complete.

58 A's message sheet 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 SEND TO A Packet 1 of 7 The SENDER S ADDRESS SEND TO A Packet 2 of 7 internet SENDER S ADDRESS

61 SEND TO A Packet 3 of 7 is SENDER S ADDRESS SEND TO A Packet 4 of 7 a SENDER S ADDRESS

62 SEND TO A Packet 5 of 7 collection SENDER S ADDRESS SEND TO A Packet 6 of 7 of SENDER S ADDRESS

63 SEND TO A Packet 7 of 7 networks SENDER S ADDRESS

64 SEND TO B Packet 1 of 9 The SENDER S ADDRESS SEND TO B Packet 2 of 9 world SENDER S ADDRESS

65 SEND TO B Packet 3 of 9 wide SENDER S ADDRESS SEND TO B Packet 4 of 9 web SENDER S ADDRESS

66 SEND TO B Packet 5 of 9 is SENDER S ADDRESS SEND TO B Packet 6 of 9 a SENDER S ADDRESS

67 SEND TO B Packet 7 of 9 collection SENDER S ADDRESS SEND TO B Packet 8 of 9 of SENDER S ADDRESS

68 SEND TO B Packet 9 of 9 pages SENDER S ADDRESS

69 SEND TO: Packet 1 of 1 NAK SENDER S ADDRESS SEND TO: Packet 1 of 1 NAK SENDER S ADDRESS

70 SEND TO: Packet 1 of 1 ACK SENDER S ADDRESS SEND TO: Packet 1 of 1 ACK SENDER S ADDRESS

71 Networks - Communication system dominoes Communication system dominoes 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. 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.

72 Networks - Communication system dominoes 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.

73 Networks - Communication system dominoes 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. 8. The first person with no dominoes left is the winner of that round.

74 Networks - Communication system dominoes Communication system dominoes 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. 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.

75 Networks - Communication system dominoes 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.