9618 · June 2024
Computer Science
Candidates should be very careful about writing their answer first in pencil and then over-writing in ink. Even after being erased the pencil markings are still picked up on the electronic scanning.
Source: Cambridge International
Cohort performance
Session statistics from official examination reports
No data available in official reports
Key examiner messages
Top priorities from the principal examiner before you revise
There is a need to use technical terminology correctly.
Candidates should be aware that using a term inappropriately can completely change an answer.
For example, it is not correct to say that because compression reduces the size of a file the transmission speed will be faster.
The transmission speed depends on factors other than the size of the file.
Question difficulty map
How candidates performed on each question in this series
9618/11
Theory Fundamentals
Assessment objectives
Skill and AO weighting from official examiner commentary
No data available in official reports
Method marks watchlist
Where working, steps, or method marks were commonly lost
No data available in official reports
Recurring mistakes across years
Themes examiners flag in multiple recent sessions for this subject
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Question choice intelligence
Mean scores and popularity for optional questions (HKDSE electives)
No data available in official reports
Level exemplars
What candidate scripts at each grade level looked like
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Grade & admission context
How marks relate to grade thresholds and entry standards
No data available in official reports
Deep insights
What top candidates did
Techniques and approaches examiners rewarded in this series
Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June…
Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June 2024 Principal Examiner Report for Teachers © 2024 COMPUTER SCIENCE Paper 9618/11 Theory Fundamentals Key messages There is a need to use technical terminology correctly. Candidates should be aware that using a term inappropriately can completely change an answer. For example, it is not correct to say that because compression reduces the size of a file the transmission speed will be faster. The transmission speed depends on factors other than the size of the file. The correct response is that because compression reduces the size of a file the time taken to transmit the file will be shorter. At this level of study some application of knowledge is expected, and candidates should ensure that they actually answer the question set. For example, if a question asks why lossy compression would not be used in a given situation, credit will not be given for just a description of lossy compression with no reference to why it is unsuitable for the scenario given in the question. When a question requires some working, for example, number base conversions or low-level language program segments, candidates should make sure that their final answer is very clearly identified. Candidates must ensure that they read the questions fully and think carefully about their answers before beginning to write. Sometimes examples are given in the stem of the question which are then explicitly excluded from accepted responses. For example, if a question states that a range check is an example of a validation check and asks for two other validation checks, no mark will be awarded if candidates give a range check as one of their answers. General comments Candidates should be very careful about writing their answer first in pencil and then over-writing in ink. Even after being erased the pencil markings are still picked up on the electronic scanning. This results in a double image which is very difficult to read. If an answer is illegible no marks can be awarded. Planning an answer or writing a first draft should be done either on any blank pages in the script or on an additional sheet of paper. In either case the rough copy should be clearly crossed through. Similarly, if candidates write a response in the answer space on the question paper and later decide that the answer is incorrect and needs to be replaced, the new version should be written either on any blank pages in the script or on an additional sheet of paper, rather than trying to squash the new answer into the existing answer space. When this happens a note for the Examiner such as, ‘Please see additional page 1’, is very helpful. Candidates should also avoid writing in the margins of the page as these can sometimes be removed during the scanning process. Comments on specific questions These comments should be read in conjunction with the published mark scheme for this paper. Question 1 (a) This question was answered well, many candidates correctly chose the second option. (b) This question was answered well, many candidates were able to draw a correct logic circuit for the given expression. The most common error was a misinterpretation of the position of the innermost brackets resulting in the circuit for NOT(NOT A AND NOT (B XOR C)) instead of the one given.
Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June…
Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June 2024 Principal Examiner Report for Teachers © 2024 Question 2 (a) This was a question where candidates were expected to apply their knowledge of embedded systems to a specific example, in this case, a video doorbell. Answers tended to fall into two groups, either a repeat of the information given in the question which just described the doorbell without any reference to it being an embedded system, or a generic description of an embedded system with no reference to the doorbell. Candidates should read the question carefully and make sure that the responses match what is being asked. (b) There were some good answers to this question, with appropriate justifications of both a monitoring and a control system. Some candidates should understand that vague answers such as, ‘it is a monitoring system because it does not control anything’ are insufficient for credit at this level of study. (c) (i) This question was answered well. The most popular correct answers were the start-up instructions and the current sensor readings. (ii) This question was not answered at all well. Some candidates were able to identify the two types of logic gates used and the number of transistors contained in each cell. Many candidates need to improve their understanding of the principal operation of solid state memory. (iii) This question was not answered well. Some candidates were able to state that a buffer was used as a temporary store for data. Many answers then included statements such as, ‘the buffer sends the video data to the secondary storage’. Candidates should be aware that statements like this demonstrate a lack of understanding, if a buffer is an area of storage, it cannot ‘do’ anything. It is a processor that ensures the data is sent from the buffer to the secondary storage. A better answer is, ‘the microprocessor in the doorbell ensures that the video data is transmitted from the buffer to the secondary storage device’. (d) This was another question where candidates were expected to apply their knowledge, and it was not answered at all well. A few candidates realised that increasing the sampling rate would increase the size of the file and that it would therefore take longer to transmit the file to the smartphone and cause the secondary storage to fill up sooner, both of which affect the performance of the doorbell. (e) (i) While there were a few good answers to this question, many candidates need to improve their understanding of what is meant by bit streaming. (ii) This question was answered well. Many candidates were able to correctly give two differences. The most popular correct answers described live versus stored content and the whether the user was able to pause, rewind etc. Question 3 (a) Many candidates were able to explain how an interpreter stops when it encounters an error, thus allowing the error to be fixed in real-time. Some otherwise correct answers were not able to be credited as candidates wrote that it was the interpreter fixing the errors rather than the developer. (b) This question was generally answered well. Many candidates were able to explain that using an executable file meant that the users had no access to the source code and so could not edit or copy it. Further explanation was more challenging. Vague statements about .exe files executing faster without any expansion are insufficient for credit at this level. Question 4 (a) There were a number of good, completely correct answers to this question. Candidates must ensure that their final answer is clearly indicated. Some candidates need to improve their understanding of the different operands used; specifically, when the operand is a value and when it is the contents of a memory location. (b) This question was also answered well. Many candidates correctly applied the logic operations to the appropriate operands. The first answer was the one most likely to be incorrect where candidates had used denary 31 for the operand rather than the contents of memory location 31.
Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June…
Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June 2024 Principal Examiner Report for Teachers © 2024 Question 5 (a) Candidates found this question challenging. Bland statements such as, ‘the server is the bank server and the client is the customer’ are insufficient. Many responses described the actions of the smartphone user, when the question asked for the roles of the different devices. When describing the role of the server, for example, the minimum that would be expected is a statement about the storage of all the customer data and another statement about receiving and processing of requests from the client. (b) There were some good, complete answers to this question. Some candidates need to improve their understanding of parity, particularly of the use of parity blocks. (c) (i) There were some good, complete answers to this question. Some candidates should be aware that vague general answers such as just, ‘a firewall blocks malicious software’ are not technical enough for credit at this level of study. (ii) There were a few interesting and imaginative answers to this question. Many candidates seemed to be familiar with the use of facial recognition on a smartphone. Some candidates need to ensure that they are describing the use of Artificial Intelligence for facial recognition, not describing the use of facial recognition for authentication. There was considerable confusion between the two. Question 6 (a) Almost all candidates were able to describe a table for the users including the fields username, email address and age. Some candidates overlooked the statement in the stem of the question that stated that the username was a unique attribute and incorrectly used the first-name and last-name combination as the primary key. Few candidates realised that the user rating would also be included in this table. The table describing each quiz often contained the correct attributes, with the filename a popular correct choice for the primary key. The linking table was a little more challenging, although some candidates recognised it as the breakdown of a standard many-to- many relationship and correctly implemented it as such. (b) Descriptions of the Data dictionary were more often correct than the descriptions of the Logical schema. Some candidates need to improve their understanding of a logical schema. Many candidates were able to state that the data dictionary contained the metadata about the database and give appropriate examples of content. A common incorrect description for the logical schema was, ‘a schema that stores the logic’. Some candidates attempted to describe logical operations within a database and wrote about the evaluation of logic expressions. A correct description of a logical schema is, ‘an implementation independent overview of the database, using a method such as an Entity-Relationship diagram’. (c) (i) There were a few correct SQL scripts. Many candidates need to improve their understanding of the syntax for the statement to add a foreign key to an existing table. (ii) In this SQL script, the FROM clause was often correct. The SELECT clause was usually attempted, but there was confusion between the use of SUM and COUNT. Several otherwise correct SELECT clauses attempted to total the data in the EventID field instead of counting the number of events for each player. The GROUP BY clause was frequently missing. Question 7 This question was answered very well. Some candidates should take care to ensure that their working is clearly visible and that any overflow is clearly indicated. Question 8 (a) This question was also answered well. Some candidates need to improve their understanding of the difference between a star topology and a mesh topology. (b) (i) This question too was answered well. Many candidates were able to correctly state what is meant by a public IP address.
Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June…
Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June 2024 Principal Examiner Report for Teachers © 2024 (ii) Many candidates were able to correctly identify two differences between IPv4 and IPv6 addresses. The most popular correct answers were the different number of bits and the different number of groups of digits. Some candidates need to ensure they read the question carefully. No mark was awarded for the different separators as this was given in the question. A small but significant number of candidates incorrectly stated that IPv6 had six groups of digits rather than eight.
Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June…
Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June 2024 Principal Examiner Report for Teachers © 2024 (b) This question was answered well, many candidates were able to draw a correct logic circuit for the given expression. The most common error was a misinterpretation of the position of the outermost brackets resulting in the circuit for NOT(A AND B) OR (B AND C) instead of the one given. Question 2 (a) There were a few good answers to this question, many candidates were able to correctly complete the first statement. Some candidates need to improve their understanding of the principal operation of a VR headset. (b) This question was not answered well. Some candidates were able to state that a buffer was used as a temporary store for data. Many answers then included statements such as, ‘the buffer sends the data to the headset’. Candidates should be aware that statements like this demonstrate a lack of understanding, if a buffer is an area of storage, it cannot ‘do’ anything. It is a microprocessor that arranges for the data to be sent from the buffer to the headset. A better answer is, ‘the microprocessor in the headset ensures that data is retrieved from the buffer’. (c) The command word in this question was ‘explain’. Many candidates were able to state the benefits of using EEPROM instead of other types of ROM but without further explanation or expansion. Candidates should be encouraged to look carefully at the command words in the question. A question that begins with the word ‘explain’ requires a different response to one that starts with the word ‘state’ or ‘identify’. (d) (i) Many of the responses to this question were very general and some described the encoding of characters rather than pixels. There were a number of references to each colour being given a code, but few responses made it clear that these codes were unique to each different colour or that the codes were then stored in the same order and sequence as the pixels in the image. Some candidates mis-interpreted the meaning of the word ‘encoded’ in the question and described different forms of compression. (ii) There were some good, complete answers to this question. Many candidates were able to correctly describe the contents of a vector graphic drawing list. Some candidates need to take greater care with the wording of their answers. Several descriptions referenced all the shapes that can be drawn, which reads as the library of shapes rather than the subset of shapes required to make up a particular image. (iii) This question was also answered well. Many candidates were able to give two correct reasons why the video did not need to be compressed. Easily the most popular answer was that there was so that there was no degradation in the quality of the video and hence the user experience was not adversely affected. Question 3 (a) (i) This was a question where candidates needed to read the stem of the question carefully. Some candidates overlooked the statements in the question that explicitly ruled out any methods of authentication, and passwords or biometric scans were popular incorrect answers. The most frequent correct answer was a firewall, and many candidates who identified this measure were also able to give a complete description. (ii) There were a number of excellent complete answers to this question. Encryption was easily the most popular correct choice. Candidates who choose to describe a particular method of encryption should be careful about stating that the encryption key is sent with the cipher text. (b) While there was a small number of good answers, there was considerable confusion here between the characteristics of thin clients and the characteristics of thick clients. Some candidates need to improve their understanding of the differences between the two. The question asked for descriptions of the characteristics as used in the exam marking software. Frequently descriptions simply repeated the characteristic with no reference to the software. Candidates should also be aware that at this level of study marks will not be awarded twice when one characteristic is the converse of the other. For example, first answer, ‘the server does most of the processing’, second answer, ‘the client does very little processing’.
Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June…
Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June 2024 Principal Examiner Report for Teachers © 2024 (c) (i) This question was generally answered well. Some candidates need to be more careful with the use of the technical terminology. ‘Package’ is not acceptable instead of ‘packet’. (ii) Many candidates found this question challenging and need to improve their understanding of the role of the Public Switched Telephone Network (PSTN) in the transmission of data over the internet. Question 4 (a) This question was answered very well. Most candidates were able to correctly identify the relationship between the given tables. (b) There were several good, completely correct SQL scripts. When the table and attribute names are given in the question candidates should take care to copy them correctly in their answers. (c) There were a small number of correct scripts, but many candidates found linking the foreign key much more challenging. A frequent error was the use of UPDATE TABLE instead of ALTER TABLE. (d) Answers to this question would have benefitted from some initial planning. Very little in the way of planning was seen on any of the scripts. Many candidates realised that a table for data about the candidates would be needed, although frequently there was no formal identification of a primary key. Identification of the other tables needed proved to be much more challenging. Some candidates attempted to modify the given tables which was not what was required. Few candidates realised that in total three additional tables would be needed to avoid any many to many relationships. Some candidates did describe a second table to link the candidates to the exams they had taken and correctly included the primary keys of the EXAM table and the STUDENT table as foreign keys. More often than not this table also included the ExamQuestionID and the marks gained by the candidate which would have been better separated out to a third table. Question 5 (a) There were a number of good, completely correct answers to this question. Candidates must ensure that their final answer is clearly indicated. Some candidates need to improve their understanding of the different operands used; specifically, when the operand is a value and when it is the contents of a memory location. (b) This question was also answered well. Many candidates correctly applied the logic operations to the appropriate operands. The first answer was the one most likely to be incorrect where candidates had used denary 29 for the operand rather than the contents of memory location 29. Question 6 Many candidates found this question challenging. There was some confusion between memory management and file management, with several responses describing utility programs such as defragmentation. Candidates should also be aware that at this level of study there is a need to demonstrate more than just general knowledge, and statements such as ‘memory management manages memory’ or ‘process management manages processes’ are far too vague for credit. The question asked for an explanation of how these two operating system management tasks supported multi-tasking, so reference to the use of memory and the allocation of other resources to several processes appearing to run simultaneously would be expected. Question 7 (a) This question was generally answered well. Some candidates need to improve their understanding of the different units of file sizes. A popular incorrect answer was 3 mebibytes. (b) Again, there were a good number of correct answers. A frequent incorrect answer was the calculation of (10 – 100) instead of (100 – 10). Some candidates should understand that when the question asks for a calculation to be completed using binary subtraction, no credit will be given for performing the calculation in denary and then converting the answer to binary.
Command word playbook
How to match each command word to the expected response style
No data available in official reports
Time traps
Sections where candidates spent disproportionate time relative to marks
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Syllabus traceability
Topics linked to questions and mark weighting in this session
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MCQ trap analytics
Commonly chosen wrong options from examiner commentary
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Topic heatmap across years
Mark concentration by topic and exam year for this subject
Mark intensity
Programming
Algorithm Design and Problem-solving
Databases
Information representation
Hardware
Difficulty trend
How session difficulty has shifted across recent years
Paper comparison
Marks and duration breakdown across papers in this session
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Marks you can still earn
Where valid approaches outside the mark scheme may still gain credit
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Practise what examiners flagged
Target weak topics from this report inside the Revui app
Self-diagnostic checklist
Key actions before you sit this paper — copy and tick off as you revise
- 1Message
There is a need to use technical terminology correctly.
- 2Message
Candidates should be aware that using a term inappropriately can completely change an answer.
- 3Message
For example, it is not correct to say that because compression reduces the size of a file the transmission speed will be faster.
- 4Message
The transmission speed depends on factors other than the size of the file.
- 5Strength
Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June…: Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June 2024 Princ
- 6Strength
Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June…: Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June 2024 Princ
- 7Strength
Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June…: Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June 2024 Princ
Teacher briefing pack
One-page session summary for tutors and classroom review
June 2024 2024
Computer Science
Cambridge International Advanced Subsidiary and Advanced Level 9618 Computer Science June 2024 Principal Examiner Report for Teachers © 2024 COMPUTER SCIENCE Paper 9618/11 Theory Fundamentals Key messages There is a need to use technical terminology correctly. Candidates should b
There is a need to use technical terminology correctly.
Candidates should be aware that using a term inappropriately can completely change an answer.
For example, it is not correct to say that because compression reduces the size of a file the transmission speed will be faster.
Examiner insights
General comments
- •Candidates should be very careful about writing their answer first in pencil and then over-writing in ink.
- •Even after being erased the pencil markings are still picked up on the electronic scanning.
- •This results in a double image which is very difficult to read.
- •If an answer is illegible no marks can be awarded.
- •Planning an answer or writing a first draft should be done either on any blank pages in the script or on an additional sheet of paper.