Cambridge Secondary 2
Example Candidate Responses
Cambridge IGCSE®
Computer Science 0478
Paper 1: Theory
In order to help us develop the highest quality Curriculum Support resources, we are undertaking a
continuous programme of review; not only to measure the success of our resources but also to
highlight areas for improvement and to identify new development needs.
We invite you to complete our survey by visiting the website below. Your comments on the quality and
relevance of Cambridge Curriculum Support resources are very important to us.
https://www.surveymonkey.co.uk/r/GL6ZNJB
Do you want to become a Cambridge consultant and help us develop support materials?
Please follow the link below to register your interest.
http://www.cie.org.uk/cambridge-for/teachers/teacherconsultants/
Cambridge International Examinations retains the copyright on all its publications. Registered Centres are
permitted to copy material from this booklet for their own internal use. However, we cannot give permission
to Centres to photocopy any material that is acknowledged to a third party even for internal use within a
Centre.
Contents
Introduction 4
Assessment at a glance 5
Paper 1: Theory 6
Question 1 6
Question 2 12
Question 3 15
Question 4 17
Question 5 20
Question 6 26
Question 7 35
Question 8 41
Question 9 44
Question 10 50
Example Candidate Responses – Paper 1: Theory
Introduction
The main aim of this booklet is to exemplify standards for those teaching Cambridge IGCSE Computer
Science 0478 – Paper 1: Theory, and to show how different levels of candidates’ performance (high, middle
and low) relate to the subject’s curriculum and assessment objectives.
In this booklet candidate responses have been chosen to exemplify a range of answers. Each response is
accompanied by a brief commentary explaining the strengths and weaknesses of the answers.
The questions, mark schemes and pre-release material used here are available to download as a zip
file from Teacher Support as the Example Candidate Responses Files. These files are:
Question Paper 12, June 2015
Question paper 0478_s15_qp_12.pdf
Mark scheme 0478_s15_ms_12.pdf
For each question there are examples of marked candidate responses each with an examiner comment on
performance. Comments are given to indicate where and why marks were awarded and how additional
marks could have been obtained. In this way, it is possible to understand what candidates have done to
gain their marks and what they still have to do to improve.
This document illustrates the standard of candidate work for those parts of the assessment which help
teachers assess what is required to achieve marks beyond what should be clear from the mark scheme.
Some question types where the answer is clear from the mark scheme, such as short answers and multiple
choice, have therefore been omitted.
Other past papers, Examiner Reports and other teacher support materials are available on Teacher Support
at https://teachers.cie.org.uk
4 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Assessment at a glance
All candidates take two papers.
All candidates take: and:
Paper 1 1 hour 45 minutes Paper 2 1 hour 45 minutes
Theory 60% Problem solving and 40%
Programming
75 marks 50 marks
Short answer and structured questions Short answer and structured questions
Questions will be based on section 1 of the Questions will be based on section 2 of the
Subject content Subject content
All questions are compulsory All questions are compulsory
No calculators are permitted 20 marks are from questions set on the pre-
Externally assessed release material*
No calculators are permitted
Externally assessed
*The pre-release material for Paper 2 Problem-solving and Programming is made available to Centres shortly after the
estimated entries deadline for the June and November examinations. For the March examination it will be made available
to Centres shortly after the 0478 Computer Science final entries deadline. It is also reproduced in the question paper.
Candidates must not bring any prepared material into the examination.
Cambridge IGCSE® Computer Science 0478 5
Example Candidate Responses – Paper 1: Theory
Paper 1: Theory
Question 1
Example candidate response – high
6 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Examiner comment – high
This candidate was able to recognise which statements were true and false about cookies. No incorrect
answers were given.
This candidate was able to match all the correct terms to the correct definitions. No terms were incorrectly
matched.
Marks awarded for 1(a) = 4/4
Marks awarded for 1(b) = 4/4
Total mark awarded = 8 out of 8
Cambridge IGCSE® Computer Science 0478 7
Example Candidate Responses – Paper 1: Theory
Example candidate response – middle
8 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Examiner comment – middle
This candidate has made a common error in their answer to 1(a). It is a common error to think that
cookies are only used in advertising. They can be used for many other reasons, such as retaining
preferences for websites.
This candidate also managed to match all the correct terms to the definitions.
Marks awarded for 1(a) = 3/4
Marks awarded for 1(b) = 4/4
Total mark awarded = 7 out of 8
Cambridge IGCSE® Computer Science 0478 9
Example Candidate Responses – Paper 1: Theory
Example candidate response – low
10 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Examiner comment – low
This candidate has made a common error in their answer to 1(a). It is a common error to think that
cookies are only used in advertising. They also made the mistake of thinking that cookies act like a
virus. Cookies are created to collect data, whereas a virus is created to corrupt data.
This candidate matched three definitions incorrectly. They mixed their understanding of the
definitions of phishing, pharming and spyware; this is a common mistake to make.
Marks awarded for 1(a) = 2/4
Marks awarded for 1(b) = 2/4
Total mark awarded = 4 out of 8
Cambridge IGCSE® Computer Science 0478 11
Example Candidate Responses – Paper 1: Theory
Question 2
Example candidate response – high
Examiner comment – high
This candidate chose capacitive as their touch screen technology. They gave a reasonably good answer for
(i), stating that capacitive is built up from layers of glass. They appear to have misunderstood the question
slightly as they then went onto give a disadvantage of the technology. This is required in the second section.
In (ii) they repeat the disadvantage they gave in (i) and now gain a mark for it. They also provide a good
advantage of the technology.
Marks awarded for 2(i) = 1/2
Marks awarded for 2(ii) = 2/2
Total mark awarded = 3 out of 4
12 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Example candidate response – middle
Examiner comment – middle
This candidate provides a good detailed response to (i). They give two correct points about infra-red
touch screen technology, stating that rays are sent across the screen and when we touch the screen
we block those rays. They then go on to explain that a signal is sent to the computer in the phone to
register where the screen is being touched, from the location of where the beams are broken.
In (ii), they provide two incorrect answers. Infra-red technology is actually expensive. There is also
no reference to what the expense relates to. It should read that it is expensive to manufacture. The
rays are also not harmful to us.
Marks awarded for (i) = 2/2
Marks awarded for (ii) = 0/2
Total mark awarded = 2 out of 4
Cambridge IGCSE® Computer Science 0478 13
Example Candidate Responses – Paper 1: Theory
Example candidate response – low
Examiner comment – low
In (i), the candidate has been very vague in their response and has not been able to demonstrate their
knowledge of how resistive technology works.
In (ii), the candidate is also vague in their advantages and disadvantages, not making any specific
points about the technology.
Marks awarded for (i) = 0/2
Marks awarded for (ii) = 0/2
Total mark awarded = 0 out of 4
14 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Question 3
Example candidate response – high
Examiner comment – high
This candidate was able to correctly match all the input devices, descriptions and applications.
Total mark awarded = 6 out of 6
Cambridge IGCSE® Computer Science 0478 15
Example Candidate Responses – Paper 1: Theory
Example candidate response – middle
Examiner comment – middle
This candidate has mixed up two of the applications. They have made the mistake of thinking that barcodes are read
from passports. This is not true in the sense of this description, it would be much more applicable to an automatic
stock control system, where the barcode is read upon purchase, and the stock level is reduced.
Total mark awarded = 5 out of 6
16 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Question 4
Example candidate response – high
Examiner comment – high
In (a) this candidate correctly states that SSL is secure sockets layer.
In (b) they manage to get the correct sequence of events when a person uses a secure website.
Marks awarded for (a) = 1/1
Marks awarded for (b) = 5/5
Total mark awarded = 6/6
Cambridge IGCSE® Computer Science 0478 17
Example Candidate Responses – Paper 1: Theory
Example candidate response - middle
Examiner comment – middle
In (a) this candidate correctly states that SSL is secure sockets layer.
In (b) they mix up stages 2 and 4 in the sequence. The browser needs the server to identify itself before it can carry out
any further stages.
Marks awarded for 4(a) = 1/1
Marks awarded for 4(b) = 3/5
Total mark awarded = 4 out of 6
18 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Example candidate response – low
Examiner comment – low
In (a), the candidate gives an incorrect response from the definition of SSL. It was a good attempt, but not
correct.
In (b), the candidate starts the sequence correctly but then gets the last three stages in the incorrect order.
The web browser needs to check the certificate is trustworthy before it will share the encrypted data.
Marks awarded for 4(a) = 0/1
Marks awarded for 4(b) = 2/5
Total mark awarded = 2 out of 6
Cambridge IGCSE® Computer Science 0478 19
Example Candidate Responses – Paper 1: Theory
Question 5
Example candidate response – high
20 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Example candidate response – high, continued
Examiner comment – high
In (a), the candidate demonstrated their knowledge of even parity by correctly identifying which bits were correctly and
incorrectly transmitted.
In (b)(i) the candidate identified the correct column and the correct byte for the error.
In (b)(ii) the candidate correctly states that byte 7 and column 6 had odd parity and it should have been even.
In (c) the candidate has correctly converted the binary number to denary. They have shown the calculation they have
used to do this, which is often a good practice to do.
In (d) the candidate has correctly described when an error would occur. Candidates need to make sure they state it
would be an even number of bits for the error to go unnoticed.
Marks awarded for (a) = 3/3
Marks awarded for (b)(i) = 2/2
Marks awarded for (b)(ii) = 2/2
Marks awarded for (c) = 1/1
Marks awarded for (d) = 1/1
Total mark awarded = 9 out of 9
Cambridge IGCSE® Computer Science 0478 21
Example Candidate Responses – Paper 1: Theory
Example candidate response – middle
22 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Example candidate response – middle, continued
Examiner comment – middle
In (a), the candidate demonstrated their knowledge of even parity by correctly identifying which bits were correctly
and incorrectly transmitted.
In (b)(i), the candidate identified the correct byte, but not the correct column. They may have identified the column
as 7 rather than 6 by including the letter column in the counting of the columns. They needed to refer to the title at
the top of the column, this should have been 6.
In (b)(ii), the candidate was able to gain a mark from stating the row and column followed odd parity, but this was
too vague for a second mark, as it did not refer to how the odd parity was identified.
In (c) the candidate gave the correct denary number.
In (d) the candidate is too vague in their answer. They start to possibly explain by saying the bits could be muddled
up. But to get a mark they would need to state that it was an even number of bits that were changed.
Marks awarded for (a) = 3/3
Marks awarded for (b)(i) = 1/2
Marks awarded for (b)(ii) = 1/2
Marks awarded for (c) = 1/1
Marks awarded for (d) = 0/1
Total mark awarded = 6 out of 9
Cambridge IGCSE® Computer Science 0478 23
Example Candidate Responses – Paper 1: Theory
Example candidate response – low
24 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Example candidate response – low, continued
Examiner comment – low
In (a), the candidate has managed to confuse odd parity with even parity. Therefore they have reversed the answer
that should have been given.
In (b)(i), the candidate has not been able to identify a correct byte or column for the error.
In (b)(ii), the candidate has mistakenly thought that the parity byte at the bottom of column 8 is incorrect as all the
others with 1’s in them are 1. They are not able to demonstrate an understanding of odd and even parity.
In (c) they did not give the correct number for the conversion.
In (d) they were not able to provide an answer. Wherever possible, candidates should try and provide some attempt
at an answer. If they are able to show some basic knowledge, they may be able to gain a mark.
Marks awarded for (a) = 0/3
Marks awarded for (b)(i) = 0/2
Marks awarded for (b)(ii) = 0/2
Marks awarded for (c) = 0/1
Marks awarded for (d) = 0/1
Total mark awarded = 0 out of 9
Cambridge IGCSE® Computer Science 0478 25
Example Candidate Responses – Paper 1: Theory
Question 6
Example candidate response – high
26 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Example candidate response – high, continued
Cambridge IGCSE® Computer Science 0478 27
Example Candidate Responses – Paper 1: Theory
Examiner comment – high
In (a) this candidate has drawn a neat and correct logic circuit. Candidates should make sure that gates are drawn
clearly and accurately as this is what is assessed first.
In (b) this candidate has correctly worked out the output for each section in the truth table. They have made good
use of the working space available to do this; it is good practice for candidates to do so.
In (c) this candidate has given the correct four outputs for the XOR gate.
Marks awarded for (a) = 5/5
Marks awarded for (b) = 4/4
Marks awarded for (c) = 1/1
Total mark awarded = 10 out of 10
28 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Example candidate response – middle
Cambridge IGCSE® Computer Science 0478 29
Example Candidate Responses – Paper 1: Theory
Example candidate response – middle, continued
30 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Examiner comment – middle
In (a) this candidate has drawn a neat and correct logic circuit. Candidates should make sure that gates are drawn
clearly and accurately as this is what is assessed first.
In (b) the candidate starts off well with one correct set of output. After this it appears that they begin to misunderstand
the logic and cannot given any further correct sets of outputs.
In (c) the candidate almost gets the correct answer, but is not quite right in their first output, so they do not get a mark.
Marks awarded for (a) = 5/5
Marks awarded for (b) = 1/4
Marks awarded for (c) = 0/1
Total mark awarded = 6 out of 10
Cambridge IGCSE® Computer Science 0478 31
Example Candidate Responses – Paper 1: Theory
Example candidate response – low
32 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Example candidate response – low, continued
Cambridge IGCSE® Computer Science 0478 33
Example Candidate Responses – Paper 1: Theory
Examiner comment – low
In (a) the candidate does not draw a logic circuit that will gain any marks. They also make a common error drawing
one of their logic gates, the NOT gate. They miss off the small circular part at the tip of the gate, in the first gate. If
candidates do this in their answer this cannot be classed as a NOT gate, as it is not drawn correctly.
In (b) the candidate is able to make two sets of correct conversions.
In (c) the candidate makes a common error with the last output. They have forgotten that if both inputs in an XOR gate
are 1, the output will be 0 and not 1, like in an OR gate.
Marks awarded for (a) = 0/5
Marks awarded for (b) = 2/4
Marks awarded for (c) = 0/1
Total mark awarded = 2 out of 10
34 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Question 7
Example candidate response – high
Cambridge IGCSE® Computer Science 0478 35
Example Candidate Responses – Paper 1: Theory
Examiner comment – high
In (a) this candidate has given a very good answer that is detailed about the process. They missed describing how the
process would avoid turning the light on and off with small changes. They would have been awarded the final mark if it
had been included.
In (b) this candidate gave three different sensors and three different applications, but only their last two were valid. It is
a common error for candidates to refer to a heat sensor, but they need to be more specific about this, for example an
infra-red sensor.
Marks awarded for (a) = 4/5
Marks awarded for (b) = 4/6
Total mark awarded = 8 out of 11
36 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Example candidate response – middle
Cambridge IGCSE® Computer Science 0478 37
Example Candidate Responses – Paper 1: Theory
Examiner comment – middle
In (a) the candidate makes two common errors at the start. A light sensor detects light but it is not aware of the
intensity of it, this is something the microprocessor calculates. Second, they refer to what the sensor sends as
information; this is incorrect as it is data at this stage because it has not been given any context or meaning. They then
go on to make two points that can gain a mark. They attempt to cover what happens to avoid small frequent changes,
but are a little too vague in their response to gain a mark, as they put two different suggestions.
In (b) the candidate cannot gain a mark for a heat sensor as they need to be more specific, for example an infrared
sensor. They also cannot gain a mark for the application for acoustic sensor. Although it is a valid explanation, it is a
repeat of the same application for pressure sensor, and each application must be different.
Marks awarded for (a) = 2/5
Marks awarded for (b) = 3/6
Total mark awarded = 5 out of 11
38 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Example candidate response – low
Cambridge IGCSE® Computer Science 0478 39
Example Candidate Responses – Paper 1: Theory
Examiner comment – low
In (a) this candidate starts off well gaining a mark in their first sentence. They then become repetitive and vague in
their response and cannot gain any further marks as a result.
In (b) they are able to gain two marks for their first sensor and application. Their second suggestion is not a sensor.
The pushing of a button may be something a sensor can detect, but is not a senor itself. They make the same mistake
stating a heat sensor. This is not specific enough and needs to refer to, for example, an infra-red sensor.
Marks awarded for (a) = 1/5
Marks awarded for (b) = 2/6
Total mark awarded = 3 out of 11
40 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Question 8
Example candidate response – high
Examiner comment – high
This candidate managed to give the correct term for all 5 definitions.
Total mark awarded = 5 out of 5
Cambridge IGCSE® Computer Science 0478 41
Example Candidate Responses – Paper 1: Theory
Example candidate response – middle
Examiner comment – middle
This candidate has made a common error and mixed up the definitions of freeware and free software.
Total mark awarded = 3 out of 5
42 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Example candidate response – low
Examiner comment – low
This candidate has made the common error of mixing up the definitions of freeware and free software. They are also
incorrect with Copyright law. This is one part of computer ethics but not the entirety, so it doesn’t match the full
definition.
Total mark awarded = 2 out of 5
Cambridge IGCSE® Computer Science 0478 43
Example Candidate Responses – Paper 1: Theory
Question 9
Example candidate response – high
44 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Example candidate response – high, continued
Examiner comment – high
In (a) this candidate has made a common error in thinking that as an interpreter interprets the code as it goes along it
might make the computer crash more easily, but it is the compiler that will in fact do this.
In (b) the candidate gave a good response stating it translates to machine code.
In (c) the candidate has provided a good response. Candidates need to make sure they state who or what the code is
easier to understand for, which this candidate did.
In (d) the candidate correctly states it allows access to specific hardware.
In (e) the candidate correctly recognised each part of code.
Marks awarded for (a) = 4/5
Marks awarded for (b) = 1/1
Marks awarded for (c) = 1/1
Marks awarded for (d) = 1/1
Marks awarded for (e) = 2/2
Total mark awarded = 9 out of 10
Cambridge IGCSE® Computer Science 0478 45
Example Candidate Responses – Paper 1: Theory
Example candidate response – middle
46 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Example candidate response – middle, continued
Examiner comment – middle
In (a) this candidate was able to correctly recognise all five statements.
In (b) the candidate has got the conversion the wrong way around. It should be from high level language to machine
code.
In (c) the candidate has not said who it is easy to understand and read for. This is needed to gain the mark.
In (d) the candidate has given an incorrect response as errors are not executed by low level language.
In (e) the candidate correctly recognised each part of code.
Marks awarded for (a) = 5/5
Marks awarded for (b) = 0/1
Marks awarded for (c) = 0/1
Marks awarded for (d) = 0/1
Marks awarded for (e) = 2/2
Total mark awarded = 7 out of 10
Cambridge IGCSE® Computer Science 0478 47
Example Candidate Responses – Paper 1: Theory
Example candidate response – low
48 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Example candidate response – low
Examiner comment – low
In (a) this candidate has mostly confused the role on a compiler and an interpreter and has got most of the statements
incorrect as a result. This is a common error that is made.
In (b) the candidate gave a good response stating it translates to machine code.
In (c) the candidate has provided a response that is just about sufficient for a mark, saying it is easier to see errors in
high-level language.
In (d) the candidate states that low level language is quicker to execute. This is a common misconception made by
candidates and is not always the case.
In (e) the candidate correctly recognised each part of code.
Marks awarded for (a) = 1/5
Marks awarded for (b) = 1/1
Marks awarded for (c) = 1/1
Marks awarded for (d) = 0/1
Marks awarded for (e) = 2/2
Total mark awarded = 5 out of 10
Cambridge IGCSE® Computer Science 0478 49
Example Candidate Responses – Paper 1: Theory
Question 10
Example candidate response – high
50 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Example candidate response – high, continued
Examiner comment – high
In (a) this candidate converted all four letters correctly
In (b) this candidate managed to perform the bit shift correctly and converted the binary to hexadecimal successfully.
Marks awarded for (a) = 2/2
Marks awarded for (b) = 4/4
Total mark awarded = 6 out of 6
Cambridge IGCSE® Computer Science 0478 51
Example Candidate Responses – Paper 1: Theory
Example candidate response – middle
52 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Examiner comment – middle
In (a) this candidate was not able to correctly convert any of the letters into binary.
In (b) this candidate did manage to perform the bit shift correctly and converted the binary to hexadecimal
successfully. This was done on an initial incorrect binary value from (a), but as they could demonstrate the skill of a bit
shift and convert those values in correct hexadecimal values, they were awarded all four marks.
Marks awarded for (a) = 0/2
Marks awarded for (b) = 4/4
Total mark awarded = 4 out of 6
Cambridge IGCSE® Computer Science 0478 53
Example Candidate Responses – Paper 1: Theory
Example candidate response – low
54 Cambridge IGCSE® Computer Science 0478
Example Candidate Responses – Paper 1: Theory
Example candidate response – low, continued
Cambridge IGCSE® Computer Science 0478 55
Example Candidate Responses – Paper 1: Theory
Examiner comment – low
In (a) the candidate was able to convert two of the letters correctly for a mark.
In (b) they did not manage to perform the bit shift correctly on either binary number, but they could
demonstrate enough skill for one mark in converting one of their binary values to the correct hex value.
Marks awarded for (a) = 1/2
Marks awarded for (b) = 1/4
Total mark awarded = 2 out of 6
56 Cambridge IGCSE® Computer Science 0478
Cambridge International Examinations
1 Hills Road, Cambridge, CB1 2EU, United Kingdom
t: +44 1223 553554 f: +44 1223 553558
e: info@cie.org.uk www.cie.org.uk
® IGCSE is the registered trademark of Cambridge International Examinations.
© Cambridge International Examinations 2016
Version 2.0
