Edexcel GCSE Computer Science (1CP2) Exam Questions

• A The next instruction (1)
• The only correct answer is A. The correct answer is the next instruction.
• B is not correct because data is fetched during the execute stage
• C is not correct because an instruction is decoded after it is fetched
• D is not correct because the program counter holds the address used to fetch the instruction

Award up to two marks for a linked description such as:

• Carries out arithmetic operations/calculations, such as addition or subtraction (1) so that the result can be stored in a register (1)
• Carries out logical operations, such as comparing two data items (1) to see which one is greater/larger (1)
• Compares two data items (1) to decide whether a condition is true / which path a program takes next (1)

Allow the result of an arithmetic or logical operation being held/stored in a register, but only where the operation is named.

Do not accept answers that say the ALU stores data or results without naming an operation (registers/main memory store data).

Do not accept answers about controlling components, decoding instructions or timing (that is the control unit or the clock).

Do not award credit for 'it processes data' on its own; an arithmetic or a logical operation must be named.

An example on its own, e.g. 'it adds two numbers', does not earn a second mark; the second mark needs a linked development.

Award up to two marks for a linked explanation such as:

• More applications/programs can be open/run at the same time (1) because more instructions and data can be held in main memory at once (1)
• Programs run faster (1) because the CPU does not have to wait for instructions/data to be read/transferred from slower secondary storage (1)
• The CPU waits/idles for less time (1) because instructions and data can be transferred to the CPU more quickly from RAM (1)

For both marks, the expansion must follow/associate with the statement.

Do not accept 'more files/photos/documents can be stored' or 'the computer has more storage' - this is a benefit of secondary storage, not RAM.

Do not accept 'the CPU becomes faster' or 'the clock speed increases'.

Indicative content

What embedded systems are used for in the drone

• An embedded system is a computer built into a larger device that performs a single, dedicated function as part of that device.
• The drone contains several embedded systems, and each one is dedicated to a task such as flight control, navigation, obstacle detection or battery monitoring rather than being a general-purpose computer.
• The flight controller embedded system processes data from the drone's sensors and changes the signals sent to the rotors, so the drone stays stable and can be steered while carrying a parcel.
• The GPS receiver embedded system works out the drone's position and uses it to navigate along the route to the customer's address.
• The camera embedded system captures images or video that are processed to detect obstacles, such as trees, buildings or overhead cables, in the drone's path.
• Sensor embedded systems, for example ultrasonic or infrared sensors, measure the distance to the ground and to obstacles so the drone can land and avoid collisions.
• The battery management and communication embedded systems monitor the charge and send the drone's status and location to the control centre, and the rotor-control embedded systems drive the rotors so the drone can take off, hover and land.

Benefits of using embedded systems in the drone

• Embedded systems use little power, so the drone can fly for longer and deliver more parcels on one charge.
• They are small and light, which is important because a heavier drone needs more power to stay in the air.
• Because each embedded system is dedicated to one task, it can respond quickly and reliably, so the drone can change direction in time to avoid an obstacle.
• Combining the processor, memory and input/output in one unit reduces the number of separate components and the cost per drone, so a fleet of delivery drones is cheaper to build.
• Embedded systems allow the drone to fly autonomously, so the company does not need a human pilot for every delivery.
• Programs are held in ROM, so the drone's behaviour is consistent and predictable each time it flies.

Any drawbacks or limitations of using embedded systems in the drone

• Each embedded system has limited processing power, so the drone may not be able to run complex obstacle-recognition software and could fail to identify an unusual obstacle.
• They have limited storage and RAM, so the drone cannot store much flight data or video on board and must send it to the control centre.
• The software is held in ROM and is difficult to update, so fixing a bug or adding a new feature may mean returning the drone or connecting it to a computer.
• The embedded systems are dedicated to the drone, so they cannot easily be reused for a different task if the drone is retired.
• If an embedded system fails, the drone may crash, which could injure people or damage property, so robustness is essential.
• A general-purpose computer would be too large and heavy for the drone, so the drone has to use these limited dedicated systems and cannot run general-purpose software.

Levels

• Level 0 (0 marks): No rewardable content.
• Level 1 (1–2 marks): Basic, independent points are made, showing elements of understanding of key concepts/principles of computer science. (AO1) The discussion will contain basic information with little linkage between points made or application to the context. (AO2)
• Level 2 (3–4 marks): Demonstrates adequate understanding of key concepts/principles of computer science. (AO1) The discussion shows some linkages and lines of reasoning with some structure and application to the context. (AO2)
• Level 3 (5–6 marks): Demonstrates comprehensive understanding of key concepts/principles of computer science to support the discussion being presented. (AO1) The discussion is well developed, with sustained lines of reasoning that are coherent and logically structured, and which clearly apply to the context. (AO2)

Additional guidance

• Level 3 responses must cover what embedded systems are used for in the drone and both benefits and drawbacks/limitations, with reasoning applied to the delivery drone. Do not accept general-purpose computer uses such as connecting to Wi-Fi to play videos, installing new software, apps or games, or using a server; do not accept the drone itself as a single embedded system unless a specific dedicated function is explained.
• A definition of an embedded system on its own, with no application to the drone, cannot lift an answer above Level 1; limited storage and inability to be repurposed must be linked to the drone, for example little flight data can be stored or the system cannot be reused for another task, to gain credit.