National Qualifications Computing Science · 2019-12-20 · National 5 Computing Science...

National Qualifications

CS(N5)16A Computing Science

Marking Instructions

© 2016 Perfect Papers – All rights reserved

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General Marking Principles for National 5 Computing Science This information is provided to help you understand the general principles you must apply when marking candidate responses to questions in this Paper. These principles must be read in conjunction with the detailed marking instructions, which identify the key. (a) Marks for each candidate response must always be assigned in line with these General Marking

Principles and the Detailed Marking Instructions for this assessment. (b) Marking should always be positive. This means that, for each candidate response, marks are

accumulated for the demonstration of relevant skills, knowledge and understanding: they are not deducted from a maximum on the basis of errors or omissions.

(c) If a specific candidate response does not seem to be covered by either the principles or detailed

Marking Instruction, you should use your professional judgement to determine the suitability and value of the candidate response.

National 5 Computing Science CS(N5)16AMS

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Number Question Instructions Marks

1 Convert the decimal number 178 into the equivalent 8-bit binary number.

10110010 (1 mark)

1

2 A computer program is created to store data about the total amount of money taken at a school raffle.

State the most suitable data type for the total.

Real (1 mark)

1

3 The pseudocode shown below uses a simple condition.

IF pass = “VIP” THEN SEND “Special Guest” TO DISPLAY

Create a complex condition that will display “standard seating” if a person has a “Reserved” pass or a “Guest” pass.

IF pass=”Reserved” OR pass=”Guest” THEN

(we only require the condition not the complete IF statement).

2 conditions correct - 1 mark

OR – 1 mark

2

4 A web browser allows a user to add bookmarks to remember websites of interest. State one other feature of a web browser.

• History of sites visited • Refresh/stop button/home

button/search box/address bar/tabbed browsing

• Change user settings (font size etc.) • Change default homepage • Customising toolbars • Adding Apps/Plugins • Other valid • 1 mark for any one bullet 1

5 This pseudocode allows the user to set the temperature for his/her central heating in degrees centigrade.

(see paper)

Complete the table below to show normal and exceptional test data for temperature.

Type of Test Data Test Data

2

Normal Anything in the range 11 to 23 (1 mark) (10 and 24 would be extreme values so not within the normal range)

Exceptional Values which are <10 or >24 are acceptable An example of text data. (1 mark)

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6 Charlie is designing a web page for a book store. Here is part of the page design. (see paper)

Give two improvements that could be made to make the page easier to use.

• Adding a search option • Clearer navigation • Breadcrumb for navigation • Images to show books/items for sale • Shopping cart options • Other valid

1 mark each bullet, max 2 marks 2

7 Explain the purpose of lines 6 to 9 in this pseudocode.

The user is required to enter a choice (1 mark)

Until the choice is greater than or equal to 1 and less than or equal to 4. (1 mark)

Note: The user will enter the choice as a string therefore the code may through an error when the string is compared (1 mark). 2

8 a Explain why web data is often compressed by a server when it is transferred to a client.

Compressing data before it leaves the server means that less data is sent to the client resulting in faster data transfer (1 mark) 1

b Explain what has to be done to the data received at the client before it can be displayed.

The data has to be decompressed (1 mark)

1

9 State the data type of the variable “found” in the code below. (see paper)

Boolean (1 mark)

1

10 Indentation of code is one method of improving the readability of program code. Describe two other methods of improving readability.

• Keyword highlighting • Internal commentary • Use of white space • Meaningful identifiers • Modular code • Use of parameter passing

1 mark for each bullet, max 2 marks 2

11 Paul has connected his games console to his next door neighbours Wi-Fi by guessing the password. State the law that he has broken.

The Computer Misuse Act (1 mark)

(The Communications Act does not apply in this instance as the access is unauthorised) 1


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12 Describe how phishing can be an online security risk.

Description of misleading email communication (1 mark)

Used to direct user to compromised credentials or to download malware (1 mark) 2

13 All of the links in this information system have been tested. (see paper)

State one other type of testing that is used in this information system.

• Matches user interface (correct layout) Spelling/Grammar

• Graphic quality • Colour scheme useable • Graphics load correctly • Works on multiple browsers 1 mark for any one bullet 1

14 The Pseudocode for a program to calculate the payment due for a number of hours worked is shown below. (see paper)

2

a Explain how the value in the variable payDue will be stored in the computer.

Using a mantissa (1 mark) and an exponent (1 mark)

Award 1 mark for floating point 1

b The programmer writing the program, implements sections of code and then tests them. During one of these tests the program stops running after a few lines and an error is reported.

i State the type of translator used by the programmer.

Interpreter (1 mark) 1

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ii State one disadvantage of using this type of translator.

• Additional RAM required. • Increased processing required (could

run more slowly). • Loops translated multiple times.

Any bullet for 1 mark

If answer given is compiler in (b)(i) then accept:

• Delay while code is compiled for testing.

• Multiple errors required when compilation fails 1

c At one point during implementation the programmer mis-types the word RECEIVE, typing RCEIVE instead.

State the type of programming error that the programmer has introduced.

Syntax error (1 mark)

1

d A diagram of a computer system is shown below. (see paper)

i Name the part of the processor labelled A above.

Registers (1 mark) 1

ii Name the part of the computer system labelled B above.

Interface (1 mark) 1

e The following part of the program is executed. (see paper)

Name the part of the computer system that will carry out each of the following tasks.

i Performs the calculation. Arithmetic Logic Unit (ALU) (1 mark) 1

ii Carries the location of payDue in main memory.

Address bus (1 mark) 1

iii Carries the result of the calculation from the processor to the main memory.

Data bus (1 mark)

1


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f This line of the program receives a value from the keyboard. (see paper)

This value should be restricted so that it is at least 1 and less than 42.

i State the standard algorithm that is used to ensure that data entered is acceptable.

Input validation (1 mark)

1

ii Using pseudocode or a programming language of your choice, write the code to ensure that only acceptable values for hoursWorked are processed.

Minimum acceptable answer

REPEAT

RECEIVE hoursWorked FROM (REAL) KEYBOARD

UNTIL hoursWorked >=1 AND hoursWorked <42

1 mark for REPEAT...UNTIL (or similar loop structure)

1 mark for hoursWorked >=1

1 mark for AND hoursWorked <42

Accept variations using DO WHILE or similar. 3

15 Here is the Computing Science section of the Perfect Papers Web Site. (see paper)

a Describe one purpose of this section of the website.

Answer identifies one aim of the Computing Science section of the Perfect Papers web site.

• Provide information about papers • Make papers available for sale

1 mark for one purpose 1

b State the domain name of this webpage URL.

perfectpapers.net (1 mark) 1

c The HTML for the logo uses the img element shown below.

<img src= “/cdn-images/pplogo.png” />

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i Name the standard file format used to store the image.

Portable Network Graphics (1 mark)

Do not accept PNG as it is stated as the file extension. 1

ii The image could have been stored using the GIF image format.

Identify two reasons why the format given in (i) above is more appropriate than GIF.

• Support for up to 24-bit colour (accept more colours)

• Support for alpha-channel transparency (gradual fades).

• Lossless compression • Progressive rendering


d The web page design includes several features to aid accessibility.

i Identify one of these features. Any one from the following: • Listen to the page option • Text resize option • Change colour scheme/Alter

background colour 1 mark for any one bullet

1

ii Explain how this feature aids accessibility.

• Screen reader reads out text of page

and graphic captions to help those with sight problems or reading difficulty to access page content.

• Text resize option can be used by those with visual impairment to enlarge text making it easier to see and read

• Changing colour scheme allows people with dyslexia or colour blindness or vision problems to access content

• Altering colour combinations makes text easier to distinguish

1 mark for any one bullet

1

e John is a teacher and can download papers from the website. Describe one concern that a teacher may have when downloading a paper from the site.

• Files may contain virus/malware • Teacher may not have software to

access files • File may be too large / use data

allowance

1 mark for any one bullet 1


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f John uses the Advanced Search section of the site to show all the Computing Science papers. (see paper)

Circle one example on the webpage above that might make use of JavaScript.

Any example of JavaScript from page (illustrating interactive or dynamic content).

Note: where multiple items have been circled on the diagram to above it would be acceptable only to circle one. 1

g Describe how the list of papers above has been sorted.

Complex sort described:

• Format • Paper

1 mark for each field used for sort 2

h Clicking on the name of a paper opens the paper’s page on the website in a new window.

Explain why the HTML code for these links uses relative addressing.

The links are internal within the perfectpapers.net web site (1 mark)

1

16 Drop Design is a web design company. The company has a number of templates which they use with clients to quickly start new website projects. One of these templates is shown below. (See paper)

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a The template shown above provides consistency of font, colour, style and size of text.

Identify other features to aid good user interface design.

Any two suitable features relating to user interface. • Interactive elements such as buttons all

same shape, size, colour • Appropriate navigation • Consistent/appropriate layout of

elements Consistent colour theme • Other valid 1 mark each feature, max 2 marks

2

b The completed web site is created using HTML.

i State the feature of HTML code that allows the pages on the website to be formatted.

elements (accept ‘tags’) (1 mark)

Accept CSS as this is now the standard for formatting. 1

ii The images for the web site are held on a separate server as shown in the diagram below. (see paper)

State the type of addressing that should be used to include the file image1.jpg in the index.html page.

Absolute (1 mark)

1

iii The server cdn.dropdesign.co.uk is part of a cloud storage service.

Describe how cloud storage can be used to provide improved access to the images for the web site.

• High availability of cloud services. • Geo-location of data (data served from

the nearest copy in ‘the cloud’. • Fail-over, if nearest cloud server is

unavailable, image taken from next available.

• Cloud services enjoy high speed data links.



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c Image1.jpg, before editing, is 5 inch by 6 inch with a resolution of 300 dpi and 16-bit colour depth. Calculate the file size of the image and state your answer in appropriate units.

Show all your working.

(5 x 300) x (6 x 300) = 2700000 (pixels) (1 mark)

2700000 x 16 = 43200000 (bits) (1 mark)

43200000 / 8 = 5400000 Bytes

5400000 / 1024 = 5273.4375 Kb

5273.4375 / 1024 = 5.15 Mb (1 mark)

1 mark for number of pixels

1 mark for number of bits

1 mark for resolving units correctly (Do not accept 5.14 Mb, do accept 5.1 Mb) 3

d The website contains a search engine.

Explain how a search engine is used to produce a list of results.

A description that includes: • matching keywords/search criteria

entered by user • database of known pages/ stored

metadata 1 mark each bullet, max 2 marks 2

17 A program is written to calculate the cost of employing road crew for a rock band tour for a number of days. Each crew member is normally paid £150 per day but will earning twice that if the crew is working in stadiums.

If there are more than 10 road crew then a tour manager is required and he/she is paid 1.5 times what the crew are paid.

An incomplete design for the program is shown below. (see paper)

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a The above design should show the type of data being entered from the keyboard in Lines 3, 4 and 6. State the most appropriate data types for the following variables.

numberofCrew:

numberOfDays:

stadiumTour:

numberofCrew: Integer (1 mark)

numberOfDays:Integer (1 mark)

stadiumTour: Boolean (1 mark)

3

b i State the lines of pseudocode that contain conditional statements.

Line 7 (1 mark)

Line 11 (1 mark) 2

ii State the part of the processor that compares the values in a conditional statement.

Arithmetic Logic Unit (1 mark)

1

c The program is later improved to store the totalCrewPay for ten different tours.

i State the data structure that would be required to store the list of totalCrewPay values.

An array (1 mark)

of real (1 mark) 2

ii State the type of loop required to repeat the code in lines 1 to 12 for each of the ten tours. Explain why this type of loop would be used.

Type of Loop:

Explanation:

Type of Loop: Fixed loop (1 mark)

Explanation: because the start/end values to repeat in the loop are known (1 mark).

2

d A logo for one of the rock bands is shown below. (see paper)

Describe how the circle element of the logo would be saved as a vector graphic.

The circle would be stored as a number of attributes:

Circle (x,y, radius, line thickness, line colour, fill colour)

Award one mark for concept of vector

Award one mark for circle(x, y, radius) as minimum. 2


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18 GuitarStore are organising the catalogue of guitars and accessories that they sell. GuitarStore want to store the details of products and the companies who manufacture them.

Some sample data is shown in the table below. (see paper)

a To avoid data duplication, a database with two linked tables is proposed – a MANUFACTURER table and a PRODUCT table.

i List the fields/attributes that should be included in each table.

MANUFACTURER PRODUCT

2

Manu Code ProductRef

Manufacturer Name Product Name

Sales Email Price

Manu Code

1 mark for correct Manufacturer table 1 mark for correct Product table

ii Identify the foreign key used to link the two tables.

Manu Code (1 mark) 1

iii Identify the primary key of the PRODUCT table.

ProductRef (1 mark) 1

b GuitarStore have created a design for a possible mobile app for their business. (see paper).

i Identify one feature that makes this a suitable user interface for a mobile app.

• Button areas which are easily touchable • Readable text on each button • Use of audio for voice search

1 mark for any bullet 1

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ii It is intended that when a visitor selects “Fender”, a list of all Fender guitars will be displayed.

Describe what happens within the database when this button is selected.

Macro/script/search program activated (1 mark)

Search carried out using Manufacturer Name field = Fender (1 mark)

2

19 Stephen has a business which creates image adverts for LCD digital signage displays in local shops, petrol stations and bus stops.(see paper)

Each digital signage display shows a number of digital images from a 128 Gigabyte memory card.

a The memory cards used in the digital signage displays are examples of solid state storage.

Explain why this is more suitable for the digital signage displays than magnetic storage.

• More power efficient • Less likely to failure • Easier to update/upgrade • Smaller size for placement in displays • Transfer / storage of data faster

to/from solid state.


b If a digital image is 50 Megabytes in size, calculate how many digital images Stephen will be able to store on a memory card before it is full.

Show your working.

128 Gb x 1024 = 131072 Mb (1 mark)

131072 / 50 = 2621.44

2621 images can be stored (1 mark)

No second mark if rounded up or if left as decimal. 2

c Stephen uses a laptop to create digital images with his clients for the digital signage displays.

Describe two advantages of using a laptop rather than a tablet or smartphone for this task.

• More complex interface allows complex manipulation of objects

• More powerful processor allows for more complex processes/effects to be applied to images.

• Greater storage options allows large amounts for data to held for processing.

• Other valid



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d Stephen is aware that he has environmental responsibilities as the owner of a business that uses computer equipment. He takes steps to reduce the carbon foot print of his business.

i Explain what is meant by a carbon footprint.

Carbon Footprint is the overall harmful emissions associated with a life of a product/time frame. (1 mark) 1

ii Describe two ways that Stephen could change the operation of the digital signage displays to use less energy.

Answer refers to the operation of signs:

Use proximity/presence detection to turn on displays when people present.

Detect light levels and set brightness accordingly.

Set a shutdown time for the displays very late at night.

Answers should not relate to energy saving component but should relate to the operation of the existing displays. 2

20 A local drone shop has a flat file database storing information on just under 10,000 products that it stocks. Part of the database is shown below. (see paper)

a The design structure of the database looks like this. (see paper)

Name two types of validation that could be applied to the field Stock ID.

Required/presence check (1 mark)

Range check (Numbers in the range 0 – 9999) *10,000 products (1 mark)

2

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b The drone store decides to change the name of the “Accessories” section to “Add-ons”. Describe a potential problem when changing this data in a flat file database design.

Potential for increased errors due to: • update anomalies • lots of changes being made 1 mark for any bullet

Answer must be a ‘description’. ‘Update Anomalies’ contains enough information to require no further description. 1

c A change is required to the database to make it more useful. The fields: InStock and Item Price

Name a suitable field type for each of the new fields.

InStock: Boolean (1 mark)

Item Price: Number (Real) (1 mark)

2


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Detail of Sources / Mark Allocations and Balance

Question Unit Area Content Mark1 SDD Low-leveloperationsand

computerarchitectureUseofbinarytorepresentandstore:integers

1

2 SDD DataTypesandStructures numeric(real) 13 SDD ComputationalConstructs useofselectionconstructsincluding

simpleandcomplexconditionalstatementsandlogicaloperators

2

4 ISDD Technicalimplementation(softwarerequirements)

webbrowsers 1

5 SDD Testinganddocumentingsolutions

normal,extremeandexceptionaltestdata

2

6 ISDD Userinterface(alsoappliesinsoftwaredesignanddevelopment)

Userrequirements(visuallayout,navigation,selection,consistency,interactivity,readability)

2

7 SDD Algorithmspecification inputvalidation 28a ISDD Mediatypes Needforcompression 18b ISDD Technicalimplementation

(softwarerequirements)webbrowsers 1

9 SDD Datatypesandstructures Booleanvariables 110 SDD Testinganddocumenting

solutionsreadabilityofcode(internalcommentary,meaningfulidentifiers,indentation)

2

11 ISDD Legalimplications ComputerMisuseAct 112 ISDD Securityrisks phishing 213 ISDD Testing/Web Linksandnavigation,¨Matchesuser

interfacedesign1

14a SDD Low-leveloperationsandcomputerarchitecture

Useofbinarytorepresentandstore:real 2

14bi SDD Low-leveloperationsandcomputerarchitecture

interpreters 1

14bii SDD Low-leveloperationsandcomputerarchitecture

interpreters 1

14c SDD Testinganddocumentingsolutions

syntaxerrors 1

14di SDD Low-leveloperationsandcomputerarchitecture

registers 1

14dii SDD Low-leveloperationsandcomputerarchitecture

interfaces 1

14ei SDD Low-leveloperationsandcomputerarchitecture

ALU 1

14eii SDD Low-leveloperationsandcomputerarchitecture

buses(address) 1

14eiii SDD Low-leveloperationsand buses(data) 1

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computerarchitecture14fi SDD Algorithmspecification inputvalidation 14fii SDD Algorithmspecification inputvalidation 315a ISDD Purpose,features,

functionality,usersDescriptionofpurpose 1

15b ISDD Structuresandlinks(web-based)

URL 1

15ci ISDD MediaTypes PNG 115cii ISDD MediaTypes AdvantagesPNG 215di ISDD Structuresandlinks(web-

based)accessibility 1

15dii ISDD Structuresandlinks(web-based)

accessibility 1

15e ISDD Securityrisks spyware,phishing,keylogging 115f ISDD Coding scriptinglanguages(includingJavaScript) 115g ISDD Structuresandlinks

(database)sort(onmultiplefields) 2

16a SDD Userinterface Userrequirements(visuallayout,navigation,selection,consistency,interactivity,readability)

2

16bi ISDD Coding mark-uplanguages(includingHTML) 116bii ISDD Structuresandlinks(web-

based)absoluteaddressing 1

16biii ISDD Technicalimplementation(storage)

cloud 2

16c ISDD MediaTypes Calculationoffilesizeforcolourbitmap. 316d ISDD Structuresandlinks(web-

based)searchengines 2

17a SDD Datatypesandstructures numeric(integer),Booleanvariables 317bi SDD Computationalconstructs useofselectionconstructsincluding

simpleandcomplexconditionalstatementsandlogicaloperators

2

17bii SDD Low-leveloperationsandcomputerarchitecture

ALU 1

17ci SDD Datatypesandstructures 1-Darrays 217cii SDD Computationalconstructs iterationandrepetitionusingfixedand

conditionalloops2

17d SDD Low-leveloperationsandcomputerarchitecture

graphics(vector) 2

18ai ISDD Structuresandlinks(database)

gooddesigntoavoiddataduplicationandmodificationerrors(insert,delete,update)

2

18aii ISDD Structuresandlinks(database)

foreignkeys 1

18aiii ISDD Structuresandlinks primarykeys 1


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(database)18bi SDD Userinterface Userrequirements(visuallayout,

navigation,selection,consistency,interactivity,readability)

1

18bii ISDD Structuresandlinks(database)

databaseoperationssearch 2

19a ISDD Technicalimplementation(storage)

solidstate 2

19b SDD Low-leveloperationsandcomputerarchitecture

Useofbinarytorepresentandstore 2

19c ISDD Technicalimplementation(hardwarerequirements)

portabledevices(includinglaptop,tablet,smartphone)

2

19di ISDD Environmentalimpact Carbonfootprint 219dii ISDD Environmentalimpact DisposalofITequipment 220a ISDD Structuresandlinks

(database)validation(includingpresencecheck,restrictedchoice,fieldlengthandrange)

2

20b SDD Structuresandlinks(database)

databasestructure:flatfile, 1

20c ISDD Structuresandlinks(database)

fieldtypes(Boolean,Number) 2

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Balance of Marks

KU/PS

Units KU PSAlgorithmspecification

6

Coding 1 1ComputationalConstructs

6

DataTypesandStructures 1 6Environmentalimpact 2 2Legalimplications 1

Low-leveloperationsandcomputerarchitecture 8 7Mediatypes 2 5Purpose,features,functionality,users

1

Securityrisks 2 1Structuresandlinks(database) 1 12Structuresandlinks(web-based) 3 3Technicalimplementation(hardwarerequirements) 2

Technicalimplementation(softwarerequirements) 2Technicalimplementation(storage) 2 2

Testinganddocumentingsolutions 2 3Testing/Web 1

Userinterface

3Userinterface(alsoappliesinsoftwaredesignanddevelopment)

2

GrandTotal 30 60


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Balance of Marks

ISDD/SDD

Units MarksISDD 47Coding 2Environmentalimpact 4Legalimplications 1Mediatypes 7Purpose,features,functionality,users 1Securityrisks 3Structuresandlinks(database) 12Structuresandlinks(web-based) 6Technicalimplementation(hardwarerequirements) 2Technicalimplementation(softwarerequirements) 2Technicalimplementation(storage) 4Testing/Web 1Userinterface(alsoappliesinsoftwaredesignanddevelopment) 2

SDD 43Algorithmspecification 6ComputationalConstructs 6DataTypesandStructures 7Low-leveloperationsandcomputerarchitecture 15Structuresandlinks(database) 1Testinganddocumentingsolutions 5Userinterface 3

GrandTotal 90

National Qualifications Computing Science · 2019-12-20 · National 5 Computing Science...

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