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Worked solutions

IB Computer Science SL · Paper 1

Computer Science, Standard Level

Session: May 2014
Marks: 70
Duration: 1 hour 30 min
Calculator: Not allowed
Questions: 14

Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 Q10 Q11 Q12 Q13 Q14

Keep your copy of the paper open alongside. We don't reproduce the questions: each part below is labelled to match the May 2014 global paper, which your school or the IB can provide.

Practice mode

Hide our working until you've had a go.

Questions 1–11 · 25 marks

Question 1

2 marks

Planning considerations for organizational IT infrastructure

System fundamentals

(a)

2 marks

Identify two critical planning dimensions for implementing a new organizational IT system:
1) User roles and access governance: Establishing user permissions, security tiers, data partition rules, and collaborative workflow requirements.
2) Technical and budgetary feasibility: Evaluating hardware/software infrastructure compatibility with legacy data alongside delivery schedules and cost limits.

Mentor tip

State two distinct feasibility dimensions such as user role permissions or legacy system compatibility.

Question 2

2 marks

Characteristics and role of beta testing

System fundamentals

(a)

2 marks

Explain the core function and timing of beta testing:
1) Pre-release evaluation by target users: Deployed in the final testing phase to a selected group of actual end users outside the development team.
2) Real-world operational validation: Uncovers unpredicted defects, usability roadblocks, and compatibility errors across diverse live user environments prior to general commercial launch.

Mentor tip

Specify that testing is conducted by real end users in live environments, distinct from internal software engineers.

Question 3

4 marks

Workplace observation method for system requirements gathering

System fundamentals

(a)

2 marks

Describe one major advantage of direct observation:
Direct verification of authentic workflows: Analysts capture actual employee actions, undocumented workarounds, and subtle procedural bottlenecks that respondents routinely overlook or misstate during surveys and interviews.

Mentor tip

Emphasize that observing genuine operational routines eliminates subjective reporting bias.

(b)

2 marks

Describe one major disadvantage of direct observation:
Hawthorne effect and high resource consumption: Individuals frequently alter regular behavioral habits when consciously aware of being observed, potentially distorting findings; furthermore, monitoring a complete business process cycle demands significant analyst time and expense.

Mentor tip

Highlight behavioral alteration due to scrutiny and the extensive time commitment involved.

Question 4

2 marks

Usability limitations of handheld mobile hardware

System fundamentals

(a)

2 marks

Outline a prominent usability hurdle in mobile interface design:
Restricted physical display area: Small screen dimensions limit readable content volume, resulting in compact virtual button targets and crowded menus that elevate input error rates, particularly under glare or while traveling.

Mentor tip

Directly link physical constraints (e.g., small screen or lack of tactile key feedback) to the specific user difficulty experienced.

Question 5

2 marks

Functional distinction between primary memory stores

Computer organisation

(a)

2 marks

Distinguish between two fundamental primary memory types:
1) Random Access Memory (RAM): Volatile read-write memory holding currently executing application machine instructions, dynamic variables, and active operating system processes.
2) Read-Only Memory (ROM): Non-volatile permanent memory storing immutable bootstrap firmware (such as the BIOS/UEFI) required to initialize system hardware during power-up.

Mentor tip

Contrast volatility and operational role: RAM stores currently running programs, while ROM stores startup boot instructions.

Question 6

2 marks

Computer-aided design (CAD) benefits and industrial application

System fundamentals

(a)

2 marks

Outline a significant benefit of computer-aided design software with an example:
1) Rapid visual prototyping and stress simulation: Engineers and architects build precise 3D virtual assemblies, testing mechanical tolerances and thermal loads prior to physical manufacturing.
2) Cost reduction and rapid iteration: For example, automotive designers modify structural vehicle frames virtually, reducing physical wind-tunnel prototyping iterations and accelerating time-to-market.

Mentor tip

Provide a concrete industrial context (e.g., aerospace or architectural design) and link 3D modeling directly to saved time or materials.

Question 7

2 marks

Digital representation of colour values

Computer organisation

(a)

2 marks

Outline how color is digitally structured and stored in memory:
1) Additive color decomposition: A color is separated into primary component intensity channels—typically Red, Green, and Blue (RGB).
2) Quantization with byte allocation: Each color channel is allocated a defined bit depth (e.g., 8 bits / 1 byte, representing integers 0 to 255), combining into a 24-bit true color representation yielding over 16.7 million variations.

Mentor tip

Mention both channel splitting (RGB components) and assigning binary bytes to quantify brightness levels.

Question 8

2 marks

Architectural features of peer-to-peer networks

Networks

(a)

2 marks

Identify two architectural properties of peer-to-peer (P2P) systems:
1) Decentralized node parity: All participating nodes (peers) possess equal operational status, functioning simultaneously as both clients and servers without depending on a centralized master server.
2) Distributed resource sharing: Bandwidth, file chunks, and processing tasks are shared dynamically across member nodes, improving resilience and eliminating single points of network failure.

Mentor tip

Emphasize the absence of a central server and the dual client/server capability of every connected peer.

Question 9

2 marks

Definition and structure of data packets

Networks

(a)

2 marks

Define the term data packet within networked communications:
1) Standardized discrete transmission unit: A formatted block into which data payloads are partitioned for routing across a packet-switched network.
2) Header and payload composition: Contains the user data payload accompanied by control metadata, including sender IP, recipient IP, sequence numbering, and error-checking checksums.

Mentor tip

Mention both the segmented data payload and the essential header control metadata (source/destination addresses and sequence IDs).

Question 10

3 marks

Factors causing variable data transmission speeds

Networks

(a)

3 marks

Explain why data transmission rates fluctuate across networks:
1) Heterogeneous physical transmission media: Network routes utilize varied infrastructure (e.g., gigabit fiber-optic trunks vs slower copper twisted-pair lines or interference-prone Wi-Fi), imposing varying theoretical bandwidth ceilings.
2) Dynamic network traffic and buffer congestion: Peak utilization leads to queuing delays at intermediate routers and packet drops, triggering latency spikes and TCP retransmissions.
3) Packet switching multi-path routing: Individual packets traverse disparate physical routes with varying hop counts and geographic distances, creating variable arrival times.

Mentor tip

Cite physical media throughput differences alongside dynamic factors like intermediate router congestion or packet rerouting.

Question 11

2 marks

Object-oriented programming objects as abstraction mechanisms

Computational thinking, problem-solving and programming

(a)

2 marks

Explain how an object embodies the computer science concept of abstraction:
1) Encapsulation and information hiding: An object bundles internal state data and algorithmic implementations, concealing complex internal mechanisms from client code.
2) Clean interface exposure: External modules interact exclusively through high-level public methods without needing to manage low-level data structures or memory representations.

Mentor tip

Emphasize hiding underlying structural complexity while presenting an intuitive public functional interface.

Questions 12–14 · 45 marks

Question 12

15 marks

Boolean logic evaluation, truth table construction, and array condition extraction

Computer organisation
Computational thinking, problem-solving and programming

(a)

3 marks

Formulate a single Boolean expression representing Harry being tired:
Given conditions for tiredness (T):
- Works and hungry: W AND H
- Works and not sunny: W AND NOT S
- Does not work and not hungry: NOT W AND NOT H
Combined Boolean sum-of-products expression:
T = (W AND H) OR (W AND NOT S) OR (NOT W AND NOT H)

T = (W \land H) \lor (W \land \neg S) \lor (\neg W \land \neg H)

Mentor tip

Combine the three independent conditions using the logical OR operator.

(b)

4 marks

Construct the complete truth table for tiredness condition T across all input combinations:
Row 0 [W=0, H=0, S=0]: NOT W AND NOT H = 1 AND 1 = 1 -> T = 1
Row 1 [W=0, H=0, S=1]: NOT W AND NOT H = 1 AND 1 = 1 -> T = 1
Row 2 [W=0, H=1, S=0]: No conditions satisfied -> T = 0
Row 3 [W=0, H=1, S=1]: No conditions satisfied -> T = 0
Row 4 [W=1, H=0, S=0]: W AND NOT S = 1 AND 1 = 1 -> T = 1
Row 5 [W=1, H=0, S=1]: No conditions satisfied -> T = 0
Row 6 [W=1, H=1, S=0]: W AND H = 1, W AND NOT S = 1 -> T = 1
Row 7 [W=1, H=1, S=1]: W AND H = 1 -> T = 1

Mentor tip

Evaluate each minterm carefully: rows 0, 1, 4, 6, and 7 evaluate to 1, while rows 2, 3, and 5 evaluate to 0.

(c)

1 mark

Identify the mathematical relationship between variable S and array index:
The truth table inputs correspond to binary integer values: Index = 4W + 2H + S.
Because S corresponds to the least significant bit (2^0):
When Index is odd, S = 1; when Index is even, S = 0 (i.e., S = Index mod 2).

S = Index (mod 2)

Mentor tip

Notice that odd index numbers have their least significant bit set to 1, corresponding to S = 1.

(d)

4 marks

Construct pseudocode algorithm TEST to extract and output W, H, S for tired states:
loop INDEX from 0 to 7
if TIRED[INDEX] == 1 then
// Extract S (bit 0)
if INDEX mod 2 == 1 then
S = 1
else
S = 0
end if
// Extract H (bit 1)
if (INDEX div 2) mod 2 == 1 then
H = 1
else
H = 0
end if
// Extract W (bit 2)
if INDEX div 4 == 1 then
W = 1
else
W = 0
end if
output W, H, S
end if
end loop

Mentor tip

Use integer division (div) and modulus (mod) to unpack the three binary bits from INDEX.

(e)

3 marks

Outline how to process collection STUDENT to identify students tired due to Work and Hunger:
1) Collection traversal: Loop through the STUDENT collection using methods hasNext() and getNext().
2) Record extraction: For each student element, retrieve their NAME and associated TIRED array.
3) Condition verification: Both Work (W=1) and Hunger (H=1) are active when binary indices have bits 1 and 2 set—specifically indices 6 (W=1, H=1, S=0) and 7 (W=1, H=1, S=1).
4) Selective output: If student.TIRED[6] == 1 or student.TIRED[7] == 1, output the student's name.

Mentor tip

Iterate across the collection and check whether TIRED[6] or TIRED[7] equals 1, since indices 6 and 7 represent W=1 and H=1.

Question 13

15 marks

SaaS architecture, security concerns, and enterprise extranets

System fundamentals
Networks

(a)

3 marks

Describe three key operational features of Software-as-a-Service (SaaS):
1) Centralized cloud hosting: Applications and databases reside on remote vendor servers rather than on local client hardware.
2) Thin-client browser access: Users interact with the software on demand via standard web browsers across existing network connections.
3) Vendor-managed maintenance: All software updates, bug patches, infrastructure scaling, and security definitions are maintained centrally by the service provider.

Mentor tip

Highlight remote infrastructure hosting, universal thin-client web access, and centralized vendor maintenance.

(b)

6 marks

Discuss key security limitations of adopting SaaS across an international enterprise:
1) Data storage governance and sovereignty: Corporate records reside on third-party servers outside the organization's direct physical control, raising risks of unauthorized provider access, data mining, or non-compliance if data centers reside in jurisdictions with weak privacy regulations.
2) Provider dependency and insolvency: If the SaaS vendor experiences unexpected bankruptcy, server host outages, or severe data corruption, corporate operations face severe interruption and possible permanent record loss.
3) Transmission interception risks: Continuous exchange of confidential enterprise data over public internet connections increases vulnerability to man-in-the-middle attacks, packet sniffing, and network downtime.

Mentor tip

Examine both storage risks (jurisdictional control, vendor viability) and transmission vulnerabilities (interception over public networks).

(c)

2 marks

Define the term extranet:
A controlled private extension of an organization's internal intranet that utilizes standard internet protocols to provide authenticated external stakeholders (such as clients, vendors, and business partners) secure access to specific organizational services and data.

Mentor tip

Clarify that it is an extended private network granting restricted, authenticated access to external stakeholders over internet protocols.

(d)

4 marks

Distinguish between a Virtual Private Network (VPN) and an Extranet:
1) Encryption and tunneling architecture: A VPN establishes an encrypted virtual tunnel across public networks, encrypting all transmitted network traffic at the packet level; an extranet provides access-controlled web portals or APIs where encryption is typically applied at the application/session layer (e.g., HTTPS).
2) Scope of network access: A VPN authenticates remote staff to grant broad access to the entire corporate LAN as if physically connected; an extranet grants strictly partitioned access restricted only to designated external web services and resources.

Mentor tip

Contrast the broad, encrypted tunnel access of a VPN with the narrow, application-specific service portal access of an extranet.

Question 14

15 marks

Automotive radio frequency management and object-oriented storage

Computational thinking, problem-solving and programming

(a)

1 mark

State the frequency value at Radio[2]:
Radio[2] contains 90.2.

Mentor tip

Index 2 corresponds to the third position in zero-based arrays.

(b)

2 marks

Outline how numerical frequencies are stored in fixed-length strings:
1) Leading zero padding: Prefix frequencies under 100 with '0' (e.g., 88.7 becomes '088.7') to fix character width to 5.
2) Character serialization: Convert each numeric digit and punctuation point into its character byte representation.

Mentor tip

Explain that numbers below 100 receive a leading '0' so all strings possess identical length.

(c)

6 marks

Construct pseudocode to calculate frequency range:
MIN = Radio[0]
MAX = Radio[0]
loop K from 1 to 5
if Radio[K] < MIN then
MIN = Radio[K]
end if
if Radio[K] > MAX then
MAX = Radio[K]
end if
end loop
RANGE = MAX - MIN
output RANGE

Mentor tip

Initialize MIN and MAX to Radio[0] before scanning the remaining elements.

(d)

2 marks

Outline how an object collection stores preset station records:
1) Class encapsulation: Define a RadioStation class encapsulating two attributes: stationName (String) and stationFrequency (Real).
2) Collection storage: When a preset is assigned, instantiate a new RadioStation object populated with the broadcast data and insert it into a dynamic collection data structure.

Mentor tip

Describe an object containing both name and frequency fields stored within a collection.

(e)

4 marks

Construct pseudocode to retrieve and display station data upon button activation:
BUTTON = readButtonPress() // Obtain pressed preset index (0 to 5)
COLLECTION.resetNext()
FOUND = false
loop while COLLECTION.hasNext() and not FOUND
ITEM = COLLECTION.getNext()
if ITEM.getButtonId() == BUTTON then
output ITEM.getName()
output ITEM.getFrequency()
FOUND = true
end if
end loop

Mentor tip

Iterate through the collection, match the button identifier, and output the associated name and frequency.

Our analysis

Where the marks are

Each part sorted by the topic it mostly tests. Computational thinking, problem-solving and programming carries the most marks on this paper.

Computational thinking, problem-solving and programming24 marks · 34%
Q11, Q12, Q14
System fundamentals21 marks · 30%
Q1, Q2, Q3, Q4, Q6, Q13
Networks13 marks · 19%
Q8, Q9, Q10, Q13
Computer organisation12 marks · 17%
Q5, Q7, Q12

Mentor insights

Traps to watch for

01
Binary bit position mapping from array index · Q12
Remember that the truth table inputs map to binary bitweights: W represents bit 2 (div 4), H represents bit 1 ((div 2) mod 2), and S represents bit 0 (mod 2). S is odd when bit 0 is 1.
02
Distinguishing VPN cryptographic tunnels from web extranets · Q13
A VPN encapsulates all network traffic within an encrypted network-layer tunnel for remote employees, whereas an extranet provides partitioned web-layer access to designated services for external clients.
03
Array range initialization logic · Q14
Always initialize MIN and MAX to the first element (Radio[0]) before the loop. Setting MIN = 0 causes MIN to incorrectly remain 0 for all positive frequencies.

Solutions and tips are GeorgeTheTutor's own; the questions are not reproduced here. Not affiliated with or endorsed by the International Baccalaureate Organization.

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Worked solutions

IB Computer Science SL · Paper 1

Computer Science, Standard Level

Session: May 2014
Marks: 70
Duration: 1 hour 30 min
Calculator: Not allowed
Questions: 14

Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 Q10 Q11 Q12 Q13 Q14

Keep your copy of the paper open alongside. We don't reproduce the questions: each part below is labelled to match the May 2014 global paper, which your school or the IB can provide.

Practice mode

Hide our working until you've had a go.

Questions 1–11 · 25 marks

Question 1

2 marks

Planning considerations for organizational IT infrastructure

System fundamentals

(a)

2 marks

Identify two critical planning dimensions for implementing a new organizational IT system:
1) User roles and access governance: Establishing user permissions, security tiers, data partition rules, and collaborative workflow requirements.
2) Technical and budgetary feasibility: Evaluating hardware/software infrastructure compatibility with legacy data alongside delivery schedules and cost limits.

Mentor tip

State two distinct feasibility dimensions such as user role permissions or legacy system compatibility.

Question 2

2 marks

Characteristics and role of beta testing

System fundamentals

(a)

2 marks

Explain the core function and timing of beta testing:
1) Pre-release evaluation by target users: Deployed in the final testing phase to a selected group of actual end users outside the development team.
2) Real-world operational validation: Uncovers unpredicted defects, usability roadblocks, and compatibility errors across diverse live user environments prior to general commercial launch.

Mentor tip

Specify that testing is conducted by real end users in live environments, distinct from internal software engineers.

Question 3

4 marks

Workplace observation method for system requirements gathering

System fundamentals

(a)

2 marks

Describe one major advantage of direct observation:
Direct verification of authentic workflows: Analysts capture actual employee actions, undocumented workarounds, and subtle procedural bottlenecks that respondents routinely overlook or misstate during surveys and interviews.

Mentor tip

Emphasize that observing genuine operational routines eliminates subjective reporting bias.

(b)

2 marks

Describe one major disadvantage of direct observation:
Hawthorne effect and high resource consumption: Individuals frequently alter regular behavioral habits when consciously aware of being observed, potentially distorting findings; furthermore, monitoring a complete business process cycle demands significant analyst time and expense.

Mentor tip

Highlight behavioral alteration due to scrutiny and the extensive time commitment involved.

Question 4

2 marks

Usability limitations of handheld mobile hardware

System fundamentals

(a)

2 marks

Outline a prominent usability hurdle in mobile interface design:
Restricted physical display area: Small screen dimensions limit readable content volume, resulting in compact virtual button targets and crowded menus that elevate input error rates, particularly under glare or while traveling.

Mentor tip

Directly link physical constraints (e.g., small screen or lack of tactile key feedback) to the specific user difficulty experienced.

Question 5

2 marks

Functional distinction between primary memory stores

Computer organisation

(a)

2 marks

Distinguish between two fundamental primary memory types:
1) Random Access Memory (RAM): Volatile read-write memory holding currently executing application machine instructions, dynamic variables, and active operating system processes.
2) Read-Only Memory (ROM): Non-volatile permanent memory storing immutable bootstrap firmware (such as the BIOS/UEFI) required to initialize system hardware during power-up.

Mentor tip

Contrast volatility and operational role: RAM stores currently running programs, while ROM stores startup boot instructions.

Question 6

2 marks

Computer-aided design (CAD) benefits and industrial application

System fundamentals

(a)

2 marks

Outline a significant benefit of computer-aided design software with an example:
1) Rapid visual prototyping and stress simulation: Engineers and architects build precise 3D virtual assemblies, testing mechanical tolerances and thermal loads prior to physical manufacturing.
2) Cost reduction and rapid iteration: For example, automotive designers modify structural vehicle frames virtually, reducing physical wind-tunnel prototyping iterations and accelerating time-to-market.

Mentor tip

Provide a concrete industrial context (e.g., aerospace or architectural design) and link 3D modeling directly to saved time or materials.

Question 7

2 marks

Digital representation of colour values

Computer organisation

(a)

2 marks

Outline how color is digitally structured and stored in memory:
1) Additive color decomposition: A color is separated into primary component intensity channels—typically Red, Green, and Blue (RGB).
2) Quantization with byte allocation: Each color channel is allocated a defined bit depth (e.g., 8 bits / 1 byte, representing integers 0 to 255), combining into a 24-bit true color representation yielding over 16.7 million variations.

Mentor tip

Mention both channel splitting (RGB components) and assigning binary bytes to quantify brightness levels.

Question 8

2 marks

Architectural features of peer-to-peer networks

Networks

(a)

2 marks

Identify two architectural properties of peer-to-peer (P2P) systems:
1) Decentralized node parity: All participating nodes (peers) possess equal operational status, functioning simultaneously as both clients and servers without depending on a centralized master server.
2) Distributed resource sharing: Bandwidth, file chunks, and processing tasks are shared dynamically across member nodes, improving resilience and eliminating single points of network failure.

Mentor tip

Emphasize the absence of a central server and the dual client/server capability of every connected peer.

Question 9

2 marks

Definition and structure of data packets

Networks

(a)

2 marks

Define the term data packet within networked communications:
1) Standardized discrete transmission unit: A formatted block into which data payloads are partitioned for routing across a packet-switched network.
2) Header and payload composition: Contains the user data payload accompanied by control metadata, including sender IP, recipient IP, sequence numbering, and error-checking checksums.

Mentor tip

Mention both the segmented data payload and the essential header control metadata (source/destination addresses and sequence IDs).

Question 10

3 marks

Factors causing variable data transmission speeds

Networks

(a)

3 marks

Explain why data transmission rates fluctuate across networks:
1) Heterogeneous physical transmission media: Network routes utilize varied infrastructure (e.g., gigabit fiber-optic trunks vs slower copper twisted-pair lines or interference-prone Wi-Fi), imposing varying theoretical bandwidth ceilings.
2) Dynamic network traffic and buffer congestion: Peak utilization leads to queuing delays at intermediate routers and packet drops, triggering latency spikes and TCP retransmissions.
3) Packet switching multi-path routing: Individual packets traverse disparate physical routes with varying hop counts and geographic distances, creating variable arrival times.

Mentor tip

Cite physical media throughput differences alongside dynamic factors like intermediate router congestion or packet rerouting.

Question 11

2 marks

Object-oriented programming objects as abstraction mechanisms

Computational thinking, problem-solving and programming

(a)

2 marks

Explain how an object embodies the computer science concept of abstraction:
1) Encapsulation and information hiding: An object bundles internal state data and algorithmic implementations, concealing complex internal mechanisms from client code.
2) Clean interface exposure: External modules interact exclusively through high-level public methods without needing to manage low-level data structures or memory representations.

Mentor tip

Emphasize hiding underlying structural complexity while presenting an intuitive public functional interface.

Questions 12–14 · 45 marks

Question 12

15 marks

Boolean logic evaluation, truth table construction, and array condition extraction

Computer organisation
Computational thinking, problem-solving and programming

(a)

3 marks

Formulate a single Boolean expression representing Harry being tired:
Given conditions for tiredness (T):
- Works and hungry: W AND H
- Works and not sunny: W AND NOT S
- Does not work and not hungry: NOT W AND NOT H
Combined Boolean sum-of-products expression:
T = (W AND H) OR (W AND NOT S) OR (NOT W AND NOT H)

T = (W \land H) \lor (W \land \neg S) \lor (\neg W \land \neg H)

Mentor tip

Combine the three independent conditions using the logical OR operator.

(b)

4 marks

Construct the complete truth table for tiredness condition T across all input combinations:
Row 0 [W=0, H=0, S=0]: NOT W AND NOT H = 1 AND 1 = 1 -> T = 1
Row 1 [W=0, H=0, S=1]: NOT W AND NOT H = 1 AND 1 = 1 -> T = 1
Row 2 [W=0, H=1, S=0]: No conditions satisfied -> T = 0
Row 3 [W=0, H=1, S=1]: No conditions satisfied -> T = 0
Row 4 [W=1, H=0, S=0]: W AND NOT S = 1 AND 1 = 1 -> T = 1
Row 5 [W=1, H=0, S=1]: No conditions satisfied -> T = 0
Row 6 [W=1, H=1, S=0]: W AND H = 1, W AND NOT S = 1 -> T = 1
Row 7 [W=1, H=1, S=1]: W AND H = 1 -> T = 1

Mentor tip

Evaluate each minterm carefully: rows 0, 1, 4, 6, and 7 evaluate to 1, while rows 2, 3, and 5 evaluate to 0.

(c)

1 mark

Identify the mathematical relationship between variable S and array index:
The truth table inputs correspond to binary integer values: Index = 4W + 2H + S.
Because S corresponds to the least significant bit (2^0):
When Index is odd, S = 1; when Index is even, S = 0 (i.e., S = Index mod 2).

S = Index (mod 2)

Mentor tip

Notice that odd index numbers have their least significant bit set to 1, corresponding to S = 1.

(d)

4 marks

Construct pseudocode algorithm TEST to extract and output W, H, S for tired states:
loop INDEX from 0 to 7
if TIRED[INDEX] == 1 then
// Extract S (bit 0)
if INDEX mod 2 == 1 then
S = 1
else
S = 0
end if
// Extract H (bit 1)
if (INDEX div 2) mod 2 == 1 then
H = 1
else
H = 0
end if
// Extract W (bit 2)
if INDEX div 4 == 1 then
W = 1
else
W = 0
end if
output W, H, S
end if
end loop

Mentor tip

Use integer division (div) and modulus (mod) to unpack the three binary bits from INDEX.

(e)

3 marks

Outline how to process collection STUDENT to identify students tired due to Work and Hunger:
1) Collection traversal: Loop through the STUDENT collection using methods hasNext() and getNext().
2) Record extraction: For each student element, retrieve their NAME and associated TIRED array.
3) Condition verification: Both Work (W=1) and Hunger (H=1) are active when binary indices have bits 1 and 2 set—specifically indices 6 (W=1, H=1, S=0) and 7 (W=1, H=1, S=1).
4) Selective output: If student.TIRED[6] == 1 or student.TIRED[7] == 1, output the student's name.

Mentor tip

Iterate across the collection and check whether TIRED[6] or TIRED[7] equals 1, since indices 6 and 7 represent W=1 and H=1.

Question 13

15 marks

SaaS architecture, security concerns, and enterprise extranets

System fundamentals
Networks

(a)

3 marks

Describe three key operational features of Software-as-a-Service (SaaS):
1) Centralized cloud hosting: Applications and databases reside on remote vendor servers rather than on local client hardware.
2) Thin-client browser access: Users interact with the software on demand via standard web browsers across existing network connections.
3) Vendor-managed maintenance: All software updates, bug patches, infrastructure scaling, and security definitions are maintained centrally by the service provider.

Mentor tip

Highlight remote infrastructure hosting, universal thin-client web access, and centralized vendor maintenance.

(b)

6 marks

Discuss key security limitations of adopting SaaS across an international enterprise:
1) Data storage governance and sovereignty: Corporate records reside on third-party servers outside the organization's direct physical control, raising risks of unauthorized provider access, data mining, or non-compliance if data centers reside in jurisdictions with weak privacy regulations.
2) Provider dependency and insolvency: If the SaaS vendor experiences unexpected bankruptcy, server host outages, or severe data corruption, corporate operations face severe interruption and possible permanent record loss.
3) Transmission interception risks: Continuous exchange of confidential enterprise data over public internet connections increases vulnerability to man-in-the-middle attacks, packet sniffing, and network downtime.

Mentor tip

Examine both storage risks (jurisdictional control, vendor viability) and transmission vulnerabilities (interception over public networks).

(c)

2 marks

Define the term extranet:
A controlled private extension of an organization's internal intranet that utilizes standard internet protocols to provide authenticated external stakeholders (such as clients, vendors, and business partners) secure access to specific organizational services and data.

Mentor tip

Clarify that it is an extended private network granting restricted, authenticated access to external stakeholders over internet protocols.

(d)

4 marks

Distinguish between a Virtual Private Network (VPN) and an Extranet:
1) Encryption and tunneling architecture: A VPN establishes an encrypted virtual tunnel across public networks, encrypting all transmitted network traffic at the packet level; an extranet provides access-controlled web portals or APIs where encryption is typically applied at the application/session layer (e.g., HTTPS).
2) Scope of network access: A VPN authenticates remote staff to grant broad access to the entire corporate LAN as if physically connected; an extranet grants strictly partitioned access restricted only to designated external web services and resources.

Mentor tip

Contrast the broad, encrypted tunnel access of a VPN with the narrow, application-specific service portal access of an extranet.

Question 14

15 marks

Automotive radio frequency management and object-oriented storage

Computational thinking, problem-solving and programming

(a)

1 mark

State the frequency value at Radio[2]:
Radio[2] contains 90.2.

Mentor tip

Index 2 corresponds to the third position in zero-based arrays.

(b)

2 marks

Outline how numerical frequencies are stored in fixed-length strings:
1) Leading zero padding: Prefix frequencies under 100 with '0' (e.g., 88.7 becomes '088.7') to fix character width to 5.
2) Character serialization: Convert each numeric digit and punctuation point into its character byte representation.

Mentor tip

Explain that numbers below 100 receive a leading '0' so all strings possess identical length.

(c)

6 marks

Construct pseudocode to calculate frequency range:
MIN = Radio[0]
MAX = Radio[0]
loop K from 1 to 5
if Radio[K] < MIN then
MIN = Radio[K]
end if
if Radio[K] > MAX then
MAX = Radio[K]
end if
end loop
RANGE = MAX - MIN
output RANGE

Mentor tip

Initialize MIN and MAX to Radio[0] before scanning the remaining elements.

(d)

2 marks

Outline how an object collection stores preset station records:
1) Class encapsulation: Define a RadioStation class encapsulating two attributes: stationName (String) and stationFrequency (Real).
2) Collection storage: When a preset is assigned, instantiate a new RadioStation object populated with the broadcast data and insert it into a dynamic collection data structure.

Mentor tip

Describe an object containing both name and frequency fields stored within a collection.

(e)

4 marks

Construct pseudocode to retrieve and display station data upon button activation:
BUTTON = readButtonPress() // Obtain pressed preset index (0 to 5)
COLLECTION.resetNext()
FOUND = false
loop while COLLECTION.hasNext() and not FOUND
ITEM = COLLECTION.getNext()
if ITEM.getButtonId() == BUTTON then
output ITEM.getName()
output ITEM.getFrequency()
FOUND = true
end if
end loop

Mentor tip

Iterate through the collection, match the button identifier, and output the associated name and frequency.

Our analysis

Where the marks are

Each part sorted by the topic it mostly tests. Computational thinking, problem-solving and programming carries the most marks on this paper.

Computational thinking, problem-solving and programming24 marks · 34%
Q11, Q12, Q14
System fundamentals21 marks · 30%
Q1, Q2, Q3, Q4, Q6, Q13
Networks13 marks · 19%
Q8, Q9, Q10, Q13
Computer organisation12 marks · 17%
Q5, Q7, Q12

Mentor insights

Traps to watch for

01
Binary bit position mapping from array index · Q12
Remember that the truth table inputs map to binary bitweights: W represents bit 2 (div 4), H represents bit 1 ((div 2) mod 2), and S represents bit 0 (mod 2). S is odd when bit 0 is 1.
02
Distinguishing VPN cryptographic tunnels from web extranets · Q13
A VPN encapsulates all network traffic within an encrypted network-layer tunnel for remote employees, whereas an extranet provides partitioned web-layer access to designated services for external clients.
03
Array range initialization logic · Q14
Always initialize MIN and MAX to the first element (Radio[0]) before the loop. Setting MIN = 0 causes MIN to incorrectly remain 0 for all positive frequencies.

Solutions and tips are GeorgeTheTutor's own; the questions are not reproduced here. Not affiliated with or endorsed by the International Baccalaureate Organization.

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