IB Computer Science Paper 1 (Topic 1, 2, 3, 6, 7)

Identify the functions of an operating system.

(1) Process management - allocates CPU time and manages running processes; (2) Memory management - allocates and deallocates RAM; (3) File system management - organizes and controls access to files; (4) Device management - controls peripherals using drivers; (5) Security management - manages authentication and access rights; (6) User interface provision - CLI or GUI; (7) Interrupt handling - manages hardware/software interrupts.

What is process management in an operating system?

Process management is the function of the OS that creates, schedules, suspends, resumes and terminates processes while allocating CPU time efficiently (e.g., via scheduling algorithms).

What is memory management in an operating system?

Memory management allocates RAM to processes, prevents unauthorized access between processes, manages virtual memory and handles paging/swapping.

What is file system management?

The OS function that organizes files into directories, manages file storage, naming, permissions and access control.

What is device management?

The OS controls hardware devices through drivers and manages input/output operations between hardware and software.

What is interrupt handling?

Interrupt handling allows the OS to respond to hardware or software signals that require immediate CPU attention (e.g., I/O completion, timer interrupts).

Explain one benefit of using a dedicated operating system instead of a generic operating system.

A dedicated OS is optimized for a specific task, resulting in improved performance, reduced resource usage, better security, greater reliability, fewer background processes, lower attack surface, and more predictable behavior (important in real-time/control systems).

What are advantages of a dedicated operating system in embedded or control systems?

(1) Optimized for specific hardware, (2) Faster boot time, (3) Lower memory usage, (4) Increased security due to limited features, (5) Greater stability, (6) Reduced power consumption, (7) More reliable real-time performance.

What are disadvantages of a dedicated operating system?

(1) Limited flexibility, (2) Less compatible with third-party software, (3) Harder to update/upgrade, (4) Higher development cost.

Explain how sensors and microprocessors maintain a constant temperature in a smart house.

A temperature sensor measures the current temperature and sends analog data to an ADC. The microprocessor compares the measured value to a preset target temperature. If there is a difference (error), the processor sends signals to an actuator (air conditioning unit). The system uses feedback in a closed-loop control system to continuously adjust output until the error is minimized.

What is a sensor in a control system?

A sensor is an input device that detects physical quantities (temperature, pressure, light) and converts them into electrical signals.

What is an actuator?

An actuator is an output device that converts electrical signals into physical action (e.g., turning on air conditioning, opening a valve).

What is a microprocessor's role in a control system?

The microprocessor processes sensor input, compares it to desired values, calculates error, and sends control signals to actuators.

What is a closed-loop control system?

A control system that uses feedback from sensors to compare actual output with desired output and automatically adjust to reduce error.

What is an open-loop control system?

A control system that does not use feedback; output is not adjusted based on actual result.

What is feedback in a control system?

Feedback is information about the system's output that is returned to the controller to reduce error.

What is the error value in a control system?

Error = Desired value (set point) − Actual measured value.

What is a set point?

The target or desired value a control system attempts to maintain (e.g., 22°C).

Why is ADC needed in temperature control systems?

Sensors often produce analog signals; the ADC (analogue to digital converter) converts them into digital signals the microprocessor can process.

What is the difference between analog and digital signals?

Analog signals are continuous; digital signals are discrete binary values.

Contrast centralized and distributed air conditioning control systems.

Centralized system: One main controller manages entire system; simpler design; single point of failure; less flexible; easier maintenance. Distributed system: Multiple controllers operate independently; more fault-tolerant; scalable; faster localized responses; more complex coordination; higher implementation cost.

What is a centralized control system?

A system where one central controller manages all sensors and actuators.

Advantages of centralized control systems

Simpler architecture, easier monitoring, lower hardware cost, easier data aggregation.

Disadvantages of centralized control systems

Single point of failure, scalability issues, possible slower response, higher network dependency.

What is a distributed control system (DCS)?

A system where multiple controllers manage different parts independently but communicate with each other.

Advantages of distributed control systems

Improved reliability (no single point of failure), scalable, faster local response, modular design, better fault isolation.

Disadvantages of distributed control systems

More complex design, higher cost, synchronization challenges, more maintenance.

Why are distributed systems often used in smart homes or industrial environments?

They improve fault tolerance, scalability, and allow independent operation if one controller fails.

What is fault tolerance?

The ability of a system to continue operating correctly even if part of it fails.

Why is real-time processing important in temperature control systems?

Real-time processing ensures sensor input is processed immediately so corrective action occurs without delay, preventing temperature overshoot or instability.

What is a real-time operating system (RTOS)?

An OS designed to process data and respond within strict timing constraints.

Why would an RTOS be suitable for a smart home temperature system?

It guarantees predictable response times, ensuring stable temperature regulation.

What is multitasking in an operating system?

The ability to run multiple processes seemingly simultaneously by allocating CPU time slices.

Why is multitasking necessary in smart home systems?

The system must manage air conditioning, alarms, surveillance and user inputs concurrently.

Identify two roles that a computer can perform in a network.

A computer in a network can act as: (1) Client - requests services/resources; (2) Server - provides services/resources; (3) Peer - acts as both client and server in P2P networks; (4) Gateway - connects different networks; (5) Proxy server - acts as intermediary for requests.

What is a client in a network?

A client is a computer that requests services, resources or data from a server.

What is a server?

A server is a computer that provides resources, services or data to clients over a network.

What is a peer-to-peer (P2P) network?

A network where each computer can act as both client and server without centralized control.

What is a gateway in networking?

A device that connects two different networks, often translating between protocols.

What is a proxy server?

A server that acts as an intermediary between a client and another server, often for security or caching.

Define the term "data packet."

A data packet is a unit of data formatted for transmission across a network. It contains a header (source address, destination address, sequence number, error checking) and payload (actual data).

What information is contained in a packet header?

Source IP, destination IP, sequence number, protocol information, error-detection data (checksum).

Why are packets used in networking?

They allow large data to be broken into smaller units, enabling efficient routing, error handling, and reassembly.

What is packet switching?

A method of transmitting data where packets travel independently through different routes and are reassembled at the destination.

Identify two reasons why fibre optic cable would be preferred over wireless connectivity.

Fibre optic is preferred because: (1) Higher bandwidth; (2) Faster transmission speed; (3) Lower latency; (4) More secure (harder to intercept); (5) Less interference; (6) More reliable over long distances.

What are advantages of fibre optic cables?

High speed, high bandwidth, low signal degradation, immunity to electromagnetic interference, secure transmission.

What are disadvantages of fibre optic cables?

Higher installation cost, fragile cables, complex installation.

What are advantages of wireless connectivity?

Mobility, easy installation, lower initial infrastructure cost.

What are disadvantages of wireless connectivity?

Interference, lower security, limited range, lower bandwidth compared to fibre.

Describe one method of implementation for a new computer system.

Implementation methods include: (1) Direct changeover - old system replaced immediately; (2) Parallel running - both systems run simultaneously; (3) Phased implementation - system introduced in stages; (4) Pilot running - introduced in one location first.

What is direct changeover?

The old system is immediately replaced by the new system; fast but high risk.

What is parallel running?

Both systems operate together until the new system is proven reliable; low risk but expensive.

What is phased implementation?

System introduced in stages; reduces risk but takes time.

What is pilot implementation?

System tested in one department/location before full rollout.

Outline one method of collecting information from stakeholders concerning requirements for a new system.

Methods include: (1) Interviews; (2) Questionnaires; (3) Observation; (4) Document analysis; (5) Workshops/focus groups; (6) Prototyping.

What are advantages of interviews?

Detailed responses, clarification possible, in-depth understanding.

What are advantages of questionnaires?

Cost-effective, large audience, quantitative analysis.

What is observation in requirements gathering?

Watching users perform tasks to identify system needs.

What is prototyping?

Creating an early model of the system to gather user feedback.

Identify two reasons why patches may be necessary for an operating system.

Patches are necessary to: (1) Fix security vulnerabilities; (2) Fix software bugs; (3) Improve performance; (4) Add compatibility; (5) Improve stability.

Identify two methods used to obtain operating system patches.

(1) Automatic updates via internet; (2) Manual download from vendor website; (3) Update via installation media; (4) Network administrator deployment.

What is a software patch?

A software update designed to fix bugs, vulnerabilities or improve functionality.

Why are security patches important?

They protect systems from malware, hacking and data breaches.

Why is hexadecimal used in computing?

It provides a compact representation of binary numbers (1 hex digit = 4 bits).

Define the term peripheral.

A peripheral is any external device connected to a computer that provides input, output, or storage but is not part of the core CPU or memory.

What are types of peripherals?

Input devices (keyboard, mouse), Output devices (monitor, printer), Storage devices (external HDD), Communication devices (network card).

Identify two features of a graphical user interface (GUI).

GUI features include: (1) Windows; (2) Icons; (3) Menus; (4) Pointer; (5) Scroll bars; (6) Toolbars; (7) Dialog boxes.

What is WIMP in GUI design?

Windows, Icons, Menus, Pointer.

Identify one common feature in application software to improve usability.

Common usability features include: (1) Help menu; (2) Tooltips; (3) Consistent layout; (4) Undo/redo; (5) Keyboard shortcuts; (6) Search function; (7) Error messages.

What is usability?

The degree to which software is easy, efficient and satisfying to use.

What are usability principles?

Consistency, feedback, simplicity, error prevention, accessibility.

What are basic logic gates?

AND, OR, NOT, NAND, NOR, XOR.

What is an AND gate?

Outputs 1 only if all inputs are 1.

What is an OR gate?

Outputs 1 if at least one input is 1.

What is a NOT gate?

Inverts input (0→1, 1→0).

What is NAND?

NOT(AND); outputs 0 only if all inputs are 1.

What is NOR?

NOT(OR); outputs 1 only if all inputs are 0.

What is XOR?

Outputs 1 if inputs are different.

What is Boolean algebra?

A mathematical system used to represent and simplify logic expressions using AND, OR, NOT operations.

Describe two hardware components needed to implement a wireless network.

A wireless network requires: (1) Wireless Access Points (WAPs) to transmit/receive Wi-Fi signals; (2) Wireless Network Interface Cards (NICs) in devices; (3) A router to manage traffic between networks; (4) Switches to connect wired infrastructure; (5) A modem for internet access; (6) Firewalls for security.

What is a Wireless Access Point (WAP)?

A device that allows wireless devices to connect to a wired network using Wi-Fi.

What is a wireless NIC?

A wireless network interface card is a hardware component that enables a device to connect to a wireless network.

What is the function of a router in a wireless network?

It routes data packets between networks and assigns IP addresses (via DHCP).

What is a network switch?

A device that connects multiple devices in a LAN and forwards data using MAC addresses.

Identify two advantages of a wireless network for students.

Advantages include: (1) Mobility — access network anywhere on campus; (2) Convenience — no physical cables required; (3) Supports BYOD devices; (4) Flexible learning environments; (5) Easier device connectivity.

What are advantages of wireless networks?

Mobility, scalability, easier installation, reduced cabling costs, flexible workspace.

What are disadvantages of wireless networks?

Security risks, interference, lower speed than fibre, signal degradation.

Outline two methods to prevent unauthorized access to wireless data.

Security methods include: (1) Encryption (WPA3/WPA2); (2) Strong authentication/password protection; (3) MAC address filtering; (4) Firewalls; (5) VPN usage; (6) Network monitoring; (7) Two-factor authentication.

What is WPA encryption?

Wi-Fi Protected Access encrypts wireless data to prevent interception.

What is MAC address filtering?

A security measure allowing only approved device MAC addresses to connect.

What is a firewall?

A security system that monitors and controls network traffic based on rules.

What is two-factor authentication (2FA)?

A security method requiring two forms of verification (password + code).

Identify two technologies required to provide a VPN.

A VPN requires: (1) VPN server software; (2) VPN client software; (3) Encryption protocols (IPSec/SSL/TLS); (4) Secure authentication system; (5) Internet connectivity.

What is a VPN?

A Virtual Private Network creates an encrypted tunnel over a public network to securely access a private network.

What encryption protocols are used in VPNs?

IPSec, SSL/TLS, OpenVPN.

Explain one benefit to staff of using a VPN for remote access.

A VPN allows secure remote access to school resources as if the user were on-site, protecting sensitive data through encryption and maintaining confidentiality.

What are benefits of VPN usage?

Secure remote access, data encryption, protects from interception, enables safe public Wi-Fi use.

What are limitations of VPNs?

Reduced speed due to encryption overhead, configuration complexity, cost of maintenance.

Outline one reason why protocols are used in communication.

Protocols ensure standardized communication rules so devices can reliably exchange data, including formatting, error handling, synchronization, and addressing.

What is a network protocol?

A set of agreed rules governing communication between devices.