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GCSE
COMPUTER SCIENCE
Paper 2 - Computing concepts
Specimen Assessment Materials Time allowed: 1 hour 45 minutes
Materials
• There are no additional materials required for this paper.
• You must not use a calculator.
Instructions
• Use black ink or black ball-point pen. Use pencil only for drawing.
• Answer all questions.
• You must answer the questions in the spaces provided.
• Do all rough work in this book.
• Cross through any work you do not want to be marked.
Information
• The total number of marks available for this paper is 90.
Advice
For the multiple-choice questions, completely fill in the lozenge alongside the appropriate answer.
CORRECT METHOD
WRONG METHODS
If you want to change your answer you must cross out your original answer as shown.
If you wish to return to an answer previously crossed out, ring the answer you now wish to select as
shown.
8525/2
2
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Answer all questions.
0 1
A bit pattern is shown in Figure 1.
Figure 1
0 1
. 1
Convert the bit pattern shown in Figure 1 into decimal.
[1 mark]
0 1
. 2
Convert the bit pattern shown in Figure 1 into hexadecimal.
[2 marks]
Answer:
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0 1
. 3
A student’s answer to the question “Why is hexadecimal often used instead of
binary?” is shown in Figure 2.
Figure 2
Because it uses fewer digits it will take up less space in a computer’s memory.
Explain why the student’s answer is incorrect.
[2 marks]
0 1
. 4
Explain how a binary number can be multiplied by 8 by shifting bits.
[2 marks]
ASCII (American Standard Code for Information Interchange) is a coding system that
can be used to represent characters. In ASCII the character A is represented by the
numeric code 65.
0 1
. 5
Shade one lozenge to indicate which character is represented by the numeric code
70.
[1 mark]
A
E
B
F
C
f
D
6
E
e
4
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0 1
. 6
Unicode is an alternative to the ASCII coding system.
State two advantages of using Unicode to represent characters instead of using
ASCII.
[2 marks]
When data is stored in a computer it is often compressed. One method that can be
used to compress text data is Huffman coding. To produce a Huffman code each
character in a piece of text is placed in a tree, with its position in the tree determined
by how often the character was used in the piece of text.
A Huffman tree for the text ZOE SAW A ZEBRA AT THE ZOO is shown in
Figure 3.
Figure 3
R
H W B
T S
E O
SPACE
Z A
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Using this Huffman tree, the Huffman coding for the character E would be the bit
pattern 110 because from the top of the tree E is to the right, then right again and then
left.
The character Z is represented by the bit pattern 010 because from the top of the tree
Z is to the left, then right and then left.
0 1
. 7
Using the Huffman code in Figure 3, complete the table to show the Huffman coding
for the characters O, SPACE and B. [3 marks]
Character Huffman coding
O
SPACE
B
0 1
. 8
Using Huffman coding, the text ZOE SAW A ZEBRA AT THE ZOO can be stored
in 83 bits.
Calculate how many additional bits are needed to store the same piece of text using
ASCII. Show your working. [3 marks]
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0 2
Bob purchases a 4GB SD card for use as secondary storage in his phone.
0 2
. 1
Calculate how many megabytes there are in 4GB. Show your working.
[2 marks]
0 2
. 2
An SD card is a type of solid state storage.
State two advantages of solid state storage compared to magnetic storage.
[2 marks]
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0 2
. 3
Many modern desktop computers have both solid state drives and magnetic hard disk
drives.
Give two reasons why desktop computers have a magnetic hard disk drive and a
solid state drive instead of having just a solid state drive.
[2 marks]
0 2
. 4
Describe how data is stored on, and read from, a magnetic hard disk.
[4 marks]
Turn over for the next question
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0 2
. 5
In recent years, there has been a large growth in the use of cloud storage.
Discuss the advantages and disadvantages of using cloud storage.
In your answer you should include an explanation of the reasons for the large growth
in recent years and consider any legal, ethical and environmental issues related to the
use of cloud storage. [9 marks]
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0 3
Most schools have a computer network.
0 3
. 1
Some schools allow teachers to access the school network from their home
computers.
Give one reason why some schools allow this and one reason why some schools do
not allow this.
[2 marks]
Reason for:
Reason against:
0 3
. 2
State three advantages of using a computer network.
[3 marks]
PANs and LANs are two different types of network.
0 3
. 3
Describe one difference between a PAN and a LAN.
[1 mark]
0 3
. 4
Give one example of where a PAN could be used.
[1 mark]
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0 3
. 5
When two computers on a network communicate with each other they need to use the
same protocol.
Define the term network protocol.
[2 marks]
For questions 0 3 . 6 to 0 3 . 8 shade one lozenge to indicate the
most suitable protocol to use in the situation described.
0 3
. 6
Used to retrieve email stored on a server
[1 mark]
A
HTTP
B
HTTPS
C
FTP
D
SMTP
E
IMAP
0 3
. 7
Used to make a payment securely when purchasing goods from a website
[1 mark]
A
HTTP
B
HTTPS
C
FTP
D
SMTP
E
IMAP
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0 3
. 8
Used to send an email from a client machine to an email server.
[1 mark]
A
HTTP
B
HTTPS
C
FTP
D
SMTP
E
IMAP
0 3
. 9
TCP/IP is a protocol used in networking. There are 4 layers in the TCP/IP stack.
Complete the table by placing the four layers of the TCP/IP stack into order (1-4)
where 1 is the top layer and 4 is the bottom layer.
[3 marks]
Layer Order (1-4)
Transport
Link
Internet
Application
0 4
Many computers use the Von Neumann architecture.
0 4
. 1
In a computer that uses the Von Neumann architecture, bit patterns can be stored in
the main memory. Shade the correct lozenge to indicate what these bit patterns could
represent. You should only shade one lozenge.
[1 mark]
A Data
B Instructions
C Data and instructions
D Data or instructions, but not both
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0 4
. 2
Five components of a CPU are given below. For each row in Table 1, choose the
letter A, B, C, D, E that best matches the description.
Letters should not be used more than once.
A. Bus
B. Arithmetic Logic Unit
C. Control Unit
D. Clock
E. Register
[3 marks]
Table 1
Description Letter
Sends a continuous series of electronic pulses
Decodes the current instruction
Completes calculations
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0 5
Social engineering is where someone is tricked or manipulated into providing secure
information or access to a secure system. Describe each of the following social
engineering techniques.
[3 marks]
Blagging:
Phishing:
Shouldering:
Turn over for the next question
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0 6
A sound engineer is recording a singer.
0 6
. 1
Describe why the sound must be converted to a digital format before it can be stored
on a computer system.
[2 marks]
0 6
. 2
The sound engineer is using a sampling rate of 2000 Hz and a sample resolution of 4
bits. What is the minimum file size of a 5-second recording? Your answer should be
given in bytes.
You should show your working.
[4 marks]
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0 6
. 3
The sound engineer currently uses a sample resolution of 4 bits which enables a
sample to be stored as one of 16 different bit patterns. She wants to increase the
number of bit patterns available from 16 to 32. Shade one lozenge which shows the
minimum sample resolution (in bits) she can choose that will allow her to do this.
[1 mark]
A 3 bits
B 5 bits
C 8 bits
D 16 bits
0 6
. 4
Shade one lozenge to show which of the following correctly states the effects of
increasing the sampling rate.
[1 mark]
A Decreases both the quality of the recording and the file size
B Has no effect on the quality of the recording or the file size
C Improves the quality of the recording and has no effect on the file size
D Improves the quality of the recording and increases the file size
Turn over for the next question
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0 7 The three examples of code shown in Figure 4 are all equivalent to one another.
Figure 4
Example 1 Example 2 Example 3
a ← 4
b ← 3
IF a = b THEN
c ← a + b
ENDIF
MOV R0, #4
MOV R1, #3
CMP R0, R1
BNE end
ADD R2, R0, R1
end:
HLT
0 7 . 1
Shade one lozenge to show the statement that is true about Figure 4.
[1 mark]
A None of the examples of code is in a low-level language.
B Only one of the examples of code is in a low-level language.
C Only two of the examples of code are in low-level languages.
D All three of the examples of code are in low-level languages.
0 7 . 2
Explain why a developer, who is good at both low-level and high-level programming,
would normally use high-level languages when writing programs.
[4 marks]
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0 7 . 3
Statements A and B refer to two different types of program translator.
Statement A: This type of translator can convert a high-level language program
into machine code. The source code is analysed fully during the translation
process. The result of this translation can be saved, meaning the translation
process does not need to be repeated.
Statement B: This type of translator was used to convert the code in
Example 2 to the code in Example 3 in Figure 4.
State the type of program translators referred to in statements A and B.
[2 marks]
Statement A:
Statement B:
Turn over for the next question
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0 8
. 1
Complete the truth table for the AND logic gate.
[1 mark]
A B A AND B
0 0
0 1
1 0
1 1
0 8
. 2
A logic circuit is being developed for an audio advert in a shop that plays automatically
if a customer is detected nearby.
• The system has two sensors, A1 and A2, that detect if a customer is near. The
audio plays if either of these sensors is activated.
• The system should only play if another audio system, S, is not playing.
• The output from the circuit, for whether the advert should play or not, is Q.
Complete the logic circuit for this system.
[3 marks]
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DO NOT WRITE ON THIS PAGE
ANSWER IN THE SPACES PROVIDED
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0 9
A relational database is being developed to store information about the games that are
available to play at a games café and the advance bookings that have been made for
those games. Each game has a unique name.
The database contains two tables: Game and Booking.
The database is currently being tested by the person who has developed it so the
database tables only contain a small amount of data that is being used for testing.
The contents of the tables are shown in Figure 5.
Figure 5
Game
Name MinPlayers MaxPlayers LengthOfGame Complexity
Friday 1 1 25 2.12
Scythe 1 5 90 3.37
Terra Mystica 2 5 100 3.95
Agricola 1 4 90 3.31
Pandemic 2 4 45 2.42
Booking
GameTableID Name Date StartTime Customer Hours
1 Friday 28/05/19 11 Hawkins 1
2 Scythe 28/05/19 11 Jemisin 1
3 Pandemic 28/05/19 15 Gormally 1
1 Pandemic 28/05/19 13 Van Perlo 2
1 Terra Mystica 29/05/19 15 Hawkins 2
0 9
. 1
State the field in the Booking table that is a foreign key.
[1 mark]
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0 9
. 2
State the most suitable data type to use for the Complexity field.
[1 mark]
0 9
. 3
Due to a change in layout at the café, the game table with an ID of 2 is no longer
suitable for games that can have more than four players. The manager needs to find
out the customer, date and time of all bookings made for the game table with an ID of
2 that are for a game that can have more than four players.
Write an SQL query that could be used to find this information for the manager. The
results should be shown in date order.
[6 marks]
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0 9
. 4
The LengthOfGame field shows the average amount of time it takes to play a game
in minutes.
A query to add 10 minutes to the length of time taken for all games that have a
Complexity of more than three is shown in Figure 6.
Figure 6
UPDATE Game
SET LengthOfGame = LengthOfGame + 9
WHERE Complexity = 3
The query contains two errors. Refine the query in Figure 6 to correct the errors.
[2 marks]
1 0
The games café is evaluating the security for their network.
1 0
. 1
State two reasons why using a biometric authentication measure is better than
password authentication for staff accounts.
[2 marks]
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1 0
. 2
Explain why it would not be appropriate for the café to use MAC address filtering on
their wireless network.
[2 marks]
END OF QUESTIONS
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ANSWER IN THE SPACES PROVIDED
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GCSE
COMPUTER SCIENCE
8525/2
Paper 2 Computing concepts
Mark scheme
Specimen Assessment Materials
MARK SCHEME – GCSE COMPUTER SCIENCE – 8525/2 – SAMS
Mark schemes are prepared by the Lead Assessment Writer and considered, together with the relevant
questions, by a panel of subject teachers. This mark scheme includes any amendments made at the
standardisation events which all associates participate in and is the scheme which was used by them in
this examination. The standardisation process ensures that the mark scheme covers the students’
responses to questions and that every associate understands and applies it in the same correct way.
As preparation for standardisation each associate analyses a number of students’ scripts. Alternative
answers not already covered by the mark scheme are discussed and legislated for. If, after the
standardisation process, associates encounter unusual answers which have not been raised they are
required to refer these to the Lead Assessment Writer.
It must be stressed that a mark scheme is a working document, in many cases further developed and
expanded on the basis of students’ reactions to a particular paper. Assumptions about future mark
schemes on the basis of one year’s document should be avoided; whilst the guiding principles of
assessment remain constant, details will change, depending on the content of a particular examination
paper.
Further copies of this mark scheme are available from
The following annotation is used in the mark scheme:
;
//
/
A
R - means a single mark - means alternative response - means an alternative word or sub-phrase - means acceptable creditworthy answer. Also used to denote a valid answer that goes beyond
the expectations of the GCSE syllabus. - means reject answer as not creditworthy
NE - means not enough
I - means ignore
DPT - in some questions a specific error made by a candidate, if repeated, could result in the
candidate failing to gain more than one mark. The DPT label indicates that this mistake should
only result in a candidate losing one mark on the first occasion that the error is made. Provided
that the answer remains understandable, subsequent marks should be awarded as if the error
was not being repeated.
MARK SCHEME – GCSE COMPUTER SCIENCE – 8525/2 – SAMS
Level of response marking instructions
Level of response mark schemes are broken down into levels, each of which has a descriptor. The
descriptor for the level shows the average performance for the level. There are marks in each level.
Before you apply the mark scheme to a student’s answer read through the answer and annotate it (as
instructed) to show the qualities that are being looked for. You can then apply the mark scheme.
Step 1 Determine a level
Start at the lowest level of the mark scheme and use it as a ladder to see whether the answer meets the
descriptor for that level. The descriptor for the level indicates the different qualities that might be seen in
the student’s answer for that level. If it meets the lowest level then go to the next one and decide if it
meets this level, and so on, until you have a match between the level descriptor and the answer. With
practice and familiarity you will find that for better answers you will be able to quickly skip through the
lower levels of the mark scheme.
When assigning a level you should look at the overall quality of the answer and not look to pick holes in
small and specific parts of the answer where the student has not performed quite as well as the rest. If
the answer covers different aspects of different levels of the mark scheme you should use a best fit
approach for defining the level and then use the variability of the response to help decide the mark within
the level, ie if the response is predominantly level 3 with a small amount of level 4 material it would be
placed in level 3 but be awarded a mark near the top of the level because of the level 4 content.
Step 2 Determine a mark
Once you have assigned a level you need to decide on the mark. The descriptors on how to allocate
marks can help with this. The exemplar materials used during standardisation will help. There will be an
answer in the standardising materials which will correspond with each level of the mark scheme. This
answer will have been awarded a mark by the Lead Examiner. You can compare the student’s answer
with the example to determine if it is the same standard, better or worse than the example. You can then
use this to allocate a mark for the answer based on the Lead Examiner’s mark on the example.
You may well need to read back through the answer as you apply the mark scheme to clarify points and
assure yourself that the level and the mark are appropriate.
Indicative content in the mark scheme is provided as a guide for examiners. It is not intended to be
exhaustive and you must credit other valid points. Students do not have to cover all of the points
mentioned in the Indicative content to reach the highest level of the mark scheme.
An answer which contains nothing of relevance to the question must be awarded no marks.
3
MARK SCHEME – GCSE COMPUTER SCIENCE – 8525/2 – SAMS
4
Qu Part Marking guidance Total
marks
01
1
Mark is for AO2 (apply)
78;
1
01
2
All marks AO2 (apply)
4; (This must be the left hand digit to gain the mark)
E; (This must be the right hand digit to gain the mark)
Maximum 1 mark: If final answer not correct.
2
01
3
All marks AO1 (understanding)
(The answer is incorrect because) the number will (still) be represented using
binary in a computer’s memory;
so it will take up the same amount of memory space;
2
01
4
All marks AO1 (understanding)
(Shifting the bit pattern) three places; to the left;
Mark as follows:
1 mark: for correct direction of shift
1 mark: for correct number of times to shift
2
01
5
Mark is for AO2 (apply)
B F;
R. If more than one lozenge shaded
1
01
6
All marks AO1 (understanding)
Advantages:
Can represent a wider range of characters;
Can represent characters from a wider range of languages;
Can represent characters used in scientific / mathematical / technical
/ specialist documents;
2
MARK SCHEME – GCSE COMPUTER SCIENCE – 8525/2 – SAMS
5
Qu Part Marking guidance Total
marks
01
7
All marks AO2 (apply)
Character Huffman coding
O 111
SPACE 10
B 00110
Mark as follows:
1 mark per correct response
3
01
8
1 mark for AO1 (understanding) and 2 marks for AO2 (apply)
7; * 26; = 182
182 – 83; = 99
Mark as follows:
1 mark for AO1: identifying number of bits (7) used to represent an ASCII
character;
1 mark for AO2: multiplying by 26;
1 mark for AO2: subtracting 83 from their answer for the number of bits used
to represent the ASCII version of the text; A. Incorrectly calculated number of
bits used for ASCII version
Maximum 1 mark: for correct answer with no working out shown
3
02
1
1 mark for AO1 (recall) and 1 mark for AO2 (apply)
1000 × 4 // 4000;;×
1 mark for AO1: identifying that there are 1000 megabytes in a gigabyte;
1 mark for AO2: multiplying by 4;
A. 1024 × 4 // 4096;;
Maximum 1 mark: If final answer not correct.
2
MARK SCHEME – GCSE COMPUTER SCIENCE – 8525/2 – SAMS
6
Qu Part Marking guidance Total
marks
02
2
All marks AO1 (understanding)
Lighter; Smaller;
Uses less power; More robust;
Generates less heat; Quieter;
Max 2
2
02
3
2 marks for AO2 (apply)
Using just solid state would cost much more;
Can get higher storage capacity by including magnetic hard disk;
2
02
4
All marks AO1 (understanding)
On a hard disk binary data represented by tiny magnetised regions;
where the magnetic orientation in one direction represents 0, and the
other direction represents 1;
When reading data the read/write head is moved (to be
over correct track); and the platter/disk spins round;
A whole sector/block read in one go (by the read/write head);
Max 4
4
MARK SCHEME – GCSE COMPUTER SCIENCE – 8525/2 – SAMS
7
Qu Part Marking guidance Total
marks
02
5
All marks AO2 (apply)
Level Description Mark Range
3 Answer demonstrates a sustained line of
reasoning with a substantiated
explanation for the recent large growth in
the use of cloud storage that includes both
technological and social reasons.
There is a logically structured
consideration of the advantages and the
disadvantages associated with the use of
cloud storage - including relevant points
covering at least two of legal, ethical and
environmental issues.
7-9
2 Answer includes an explanation for the
recent large growth in the use of cloud
storage that includes both technological
and social reasons.
There is a logically structured
consideration of the advantages and the
disadvantages associated with the use of
cloud storage - including one or two
relevant points related to legal, ethical and
environmental issues.
4-6
1 The answer includes either a description of
some of the reasons for the recent large
growth in the use of cloud computing
and/or brief consideration of the
advantages and/or disadvantages
associated with using cloud storage.
1-3
No creditworthy answer 0
9
MARK SCHEME – GCSE COMPUTER SCIENCE – 8525/2 – SAMS
8
Guidance - Indicative Response (reasons for growth)
Higher bandwidth mobile networks (eg 4G);
Increased availability of mobile devices;
Reduction in cost of large capacity storage devices;
Improvements in network security;
People have a higher level of trust in cloud storage;
Improvements in web browser software;
Increased availability of supercomputers (for cloud processing);
Companies have managed to develop business models based on cloud
computing that allow them to make a profit;
Guidance - Indicative Response (advantages of cloud storage)
Enables user to access their data from more places/devices;
Enables user to more easily share data with others (can make parts of their
cloud storage publically available);
Increases the amount of storage available;
Reduced cost of computing devices for users as no need for as much
built-in secondary storage;
Guidance - Indicative Response (disadvantages of cloud storage)
Increased security risks;
Relies on access to high-bandwidth network connection; Could
potentially cost more due to ongoing costs; Reliance on company
providing the cloud service;
Increased chance of others accessing personal data (data privacy
issues);
MARK SCHEME – GCSE COMPUTER SCIENCE – 8525/2 – SAMS
9
Qu Part Marking guidance Total
marks
03
1
All marks AO1 (understanding)
Reasons for allowing:
Teachers can access resources on the school network to allow
them to plan lessons at home;
Teachers can teach lessons from home (using
videoconferencing) if they are not able to get into work (eg
travel difficulties);
Teachers can access electronic copies of student work so that
they do not have to carry marking home;
Reasons for not allowing:
Data protection issues – schools may not want potentially
sensitive student information to be accessed outside of school;
To try to help teachers have a work-life balance;
Increased security risks as teachers may not have fully
protected computers at home (eg if a teacher does not have
anti-virus software on their home computer this may cause
problems when they connect their computer to the school
network);
Max 1 mark: if only described reasons for allowing access
Max 1 mark: if only described reasons for not allowing access
2
03
2
All marks AO1 (understanding)
Share hardware; A. by example
Share data/files;
Easier to work collaboratively;
Use of communication tools
Central management for machines A. by example: centralised software
deployment, centralised back-ups;
Files not stored on local machine so can be accessed from multiple machines;
Can monitor computer users;
Increase available storage;
Max 3 marks
3
MARK SCHEME – GCSE COMPUTER SCIENCE – 8525/2 – SAMS
10
03
3
1 mark for AO1 (understanding)
PANs are centred around one person, LANs cover a limited
geographical area / LANs cover a larger area;
PANs have one user, LANs (normally) have more than one user;
PAN uses Bluetooth, LAN uses alternative protocols / connection methods (A. by
example);
Note: answer must cover both PAN and LAN to be awarded a mark
Max 1
1
03
4
1 mark for AO1 (understanding)
Wearable computing devices;
Connecting headphones to a music player;
Connecting pedometer to a mobile phone;
A. any suitable example
Max 1
1
03
5
All marks AO1 (recall)
a set of rules;
that allow two devices to communicate;
2
03
6
Mark is for AO1 (recall)
E IMAP;
R. If more than one lozenge shaded
1
03
7
Mark is for AO1 (recall)
B HTTPS;
R. If more than one lozenge shaded
1
Qu Part Marking guidance Total
marks
MARK SCHEME – GCSE COMPUTER SCIENCE – 8525/2 – SAMS
11
03
8
Mark is for AO1 (recall)
D SMTP;
R. If more than one lozenge shaded
1
03
9
All marks AO1 (recall)
Layer
Order (1-4)
Transport
2
Link
4
Network
3
Application
1
Mark as follows:
1 mark: any row correct;
2 marks: any two rows correct;
3 marks: all four rows correct;
3
Qu Part Marking guidance Total
marks
MARK SCHEME – GCSE COMPUTER SCIENCE – 8525/2 – SAMS
12
Qu Part Marking guidance Total
marks
04 1 1 marks for AO1 (understanding)
C Data and instructions;
R. If more than one lozenge shaded
1
04 2 3 marks for AO1 (understanding)
Description Letter
Sends a continuous series of electronic pulses D;
Decodes the current instruction C;
Completes calculations B;
Mark as follows:
1 mark: one row correct;
2 marks: two rows correct;
3 marks: all rows correct;
3
5 3 marks for AO1 (understanding)
1 mark each for describing the social engineering technique.
Blagging
This is where a victim is tricked/persuaded by a fraudster to give their details or
payment information for a false reason/purpose;
Phishing
Is where the victim receives and responds to a communication that appears to be
from a valid or known source but is in fact fraudulent. (It allows the fraudster to
capture private information before the victim realises);
Shouldering
This is where someone watches and recordsremembers a victim entering their
pin or security information such as passwords. (They can then use this
information to gain access to a system);
3
MARK SCHEME – GCSE COMPUTER SCIENCE – 8525/2 – SAMS
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Qu Part Marking guidance Total
marks
06 1 2 marks for AO1 (understanding)
Maximum of 2 from:
Computer systems use binary/ones and zeros/voltage on or off;
Sound is analogue/continuous;
Computers use digital data/discrete values;
2
06 2 4 marks for AO2 (apply)
4 marks if answer is correct
5,000 bytes/5,000B;;;;
A. 5,000
If answer given is not 5,000 bytes then award working marks as follows:
Mark A for multiplying any two of 2,000, 4 and 5 even if the result is incorrect;
Mark B for multiplying all of 2,000, 4 and 5 even if the result is incorrect;
Mark C for attempting to divide the result of a multiplication by 8;
Partially correct examples:
Example 1
2,000 * 4 = 8,000; (Mark A)
8,000 / 8 = 1,000; (Mark C)
Example 2
2,000 * 4 * 5 = 20,000;; (Mark A and Mark B, note result is incorrect)
20,000 / 8 = 2,000; (Mark C, note result is incorrect)
4
MARK SCHEME – GCSE COMPUTER SCIENCE – 8525/2 – SAMS
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Qu Part Marking guidance Total
marks
06 3 Mark is for AO2 (apply)
B 5 bits;
R. If more than one lozenge shaded
1
06 4 Mark is for AO2 (apply)
D Improves the quality of the recording and increases the file size;
R. If more than one lozenge shaded
1
07 1 Mark is for AO1 (understanding)
C Only two of the examples of code are in low-level languages;
R. If more than one lozenge shaded
1
07 2 4 marks for AO1 (understanding)
Maximum four marks from:
• High-level languages have built-in functions;
• High-level languages have built-in libraries;
• High-level languages have more support/help;
• High-level languages have structures (such as selection and iteration);
• High-level languages can be less machine dependent/more portable;
• It (usually) requires fewer lines of code to be written;
• It is (usually) quicker to develop code in high-level languages;
• It is easier to find mistakes in code;
• The code is easier to maintain//understand;
• It is easier to structure code in high-level languages;
NE. references to efficiency or speed unless correctly qualified;
A. Easier to read in place of easier to understand on this occasion;
R. Answers relating to programmer expertise;
4
07 3 2 marks for AO1 (understanding)
[Statement A:] compiler;
[Statement B:] assembler;
2
MARK SCHEME – GCSE COMPUTER SCIENCE – 8525/2 – SAMS
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Qu Part Marking guidance Total
marks
08 1 Mark is for AO1 (understanding)
Only reward if column A AND B is completely correct;
A B A AND B
0 0 0
0 1 0
1 0 0
1 1 1
1
08 2 3 marks for AO2 (apply)
Max 2 marks if not fully correct (the fully correct answer is given in example 1).
Mark A if A1 and A2 are the inputs to an OR gate;
Mark B if S is the input to a NOT gate;
Mark C if the output from an AND gate is Q;
Example 1 (Fully correct answer)
See next page for partially correct answers
3
MARK SCHEME – GCSE COMPUTER SCIENCE – 8525/2 – SAMS
16
Example 2 (Marks B and C)
Example 3 (Marks B and C)
Example 4 (Marks A and B)
MARK SCHEME – GCSE COMPUTER SCIENCE – 8525/2 – SAMS
17
Qu Part Marking guidance Total
marks
09 1 1 mark for AO2 (apply)
Name;
1
09 2 1 mark for AO2 (apply)
Real // Float // Decimal;
1
09 3 6 marks for AO3 (program)
1 mark: correct fields in SELECT clause
1 mark: one correct table in FROM clause
1 mark: second correct table in FROM clause
1 mark: a correct condition in WHERE clause
1 mark: correct conditions and correct usage of AND in WHERE clause // correct
conditions and correct usage of AND in WHERE clause and correct usage of ON
with INNER JOIN
1 mark: ORDER BY clause
Max 5 if any errors
Sample answer
SELECT Customer, Date, Time
FROM Booking, Game
WHERE Booking.Name = Game.Name
AND MaxPlayers = 4
AND GameTableID = 2
ORDER BY Date
I. the inclusion of ASC, DESC in ORDER BY clause
Alternative answer
SELECT Customer, Date, Time
FROM Booking INNER JOIN Game ON Booking.Name = Game.Name
WHERE MaxPlayers = 4
AND GameTableID = 2
ORDER BY Date
6
MARK SCHEME – GCSE COMPUTER SCIENCE – 8525/2 – SAMS
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Qu Part Marking guidance Total
marks
09 4 2 marks for AO3 (refine)
1 mark: changing +9 to +10;
1 mark: changing =3 to 3
UPDATE Game
SET LengthOfGame = LengthOfGame + 10
WHERE Complexity 3
2
10
1
All marks AO2 (apply)
Staff could forget their password // staff can’t forget biometric measure;
Shouldering risk when staff entering their password // no risk of shouldering when
using biometric data;
Lower risk of hacking;
Max 2
2
10
2
All marks AO2 (apply)
Network is made available to members of the public;
Won’t know the MAC addresses for (most) of the devices connecting to the network;
2
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Content preview
Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signature
GCSE
COMPUTER SCIENCE
Paper 2 - Computing concepts
Specimen Assessment Materials Time allowed: 1 hour 45 minutes
Materials
• There are no additional materials required for this paper.
• You must not use a calculator.
Instructions
• Use black ink or black ball-point pen. Use pencil only for drawing.
• Answer all questions.
• You must answer the questions in the spaces provided.
• Do all rough work in this book.
• Cross through any work you do not want to be marked.
Information
• The total number of marks available for this paper is 90.
Advice
For the multiple-choice questions, completely fill in the lozenge alongside the appropriate answer.
CORRECT METHOD WRONG METHODS
If you want to change your answer you must cross out your original answer as shown.
If you wish to return to an answer previously crossed out, ring the answer you now wish to select as
shown.
8525/2
, 2
Do not write
outside the
box
Answer all questions.
0 1 A bit pattern is shown in Figure 1.
Figure 1
01001110
0 1 . 1 Convert the bit pattern shown in Figure 1 into decimal.
[1 mark]
0 1 . 2 Convert the bit pattern shown in Figure 1 into hexadecimal.
[2 marks]
Answer:
, 3
Do not write
outside the
0 1 . 3 A student’s answer to the question “Why is hexadecimal often used instead of box
binary?” is shown in Figure 2.
Figure 2
Because it uses fewer digits it will take up less space in a computer’s memory.
Explain why the student’s answer is incorrect.
[2 marks]
0 1 . 4 Explain how a binary number can be multiplied by 8 by shifting bits.
[2 marks]
ASCII (American Standard Code for Information Interchange) is a coding system that
can be used to represent characters. In ASCII the character A is represented by the
numeric code 65.
0 1 . 5 Shade one lozenge to indicate which character is represented by the numeric code
70.
[1 mark]
A E
B F
C f
D 6
E e
Turn
Turn over
over ►►
, 4
Do not write
outside the
0 1 . 6 Unicode is an alternative to the ASCII coding system. box
State two advantages of using Unicode to represent characters instead of using
ASCII.
[2 marks]
When data is stored in a computer it is often compressed. One method that can be
used to compress text data is Huffman coding. To produce a Huffman code each
character in a piece of text is placed in a tree, with its position in the tree determined
by how often the character was used in the piece of text.
A Huffman tree for the text ZOE SAW A ZEBRA AT THE ZOO is shown in
Figure 3.
Figure 3
SPACE
Z E O
A
S T
R H B W