Edexcel GCSE Computer Science (1CP2) Exam Questions

• B 7 (1)
• The only correct answer is B. The correct answer is 7.
• A is not correct because 6 bits give only 64 combinations, which is not enough for 70 characters
• C is not correct because 7 bits already give 128 combinations, so 8 bits is not the minimum needed
• D is not correct because 70 is the number of characters needed, not a number of bits

• C Tebibyte (1)
• The only correct answer is C. The correct answer is tebibyte.
• A is not correct because a gibibyte is 1024 mebibytes
• B is not correct because a mebibyte is 1024 kibibytes
• D is not correct because a terabyte is 1000 gigabytes

Award one mark for any of the following up to a maximum of two marks:

• A network that covers a small geographical area / is on a single site / is within one building (1)
• (Two or more) computers/devices connected together (1)
• So that the connected devices can share data/files/resources such as printers or an internet connection (1)
• Uses cabling/infrastructure owned by the organisation (1)

Do not accept a network that covers a large geographical area / connects networks in different countries, as this describes a WAN.

Do not accept 'a network in a school' on its own, as this repeats the stem without a LAN feature such as a single site or connected devices.

Do not accept 'a network that connects to the internet' without a LAN feature such as a single site or connected devices.

Do not accept 'owned by one organisation' on its own, as a WAN can also be owned by one organisation.

Do not accept 'local' on its own without saying what it means.

The share mark needs the sharing to be linked to the connected devices/network, e.g. 'share files' or 'share printers'.

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

• Existing data would be lost (1) because the new file would overwrite/replace its contents (1)
• The original file could not be recovered (1) because its contents would be destroyed/replaced (1)
• A program that uses the existing file would fail (1) because the file's data would have been changed/removed (1)
• The user could lose important work (1) because the old file is replaced by the new one (1)

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

Do not accept 'so files do not have the same name' without a reason linked to loss of data.

Do not accept 'to keep files tidy' or 'so the computer does not crash' without a reason linked to the existing file's contents being lost.

Award one mark for each correct digit in the correct position:

• 5 (1)
• A (1)

Answer: 5A

Award one mark for each correct nibble in the correct order:

• 0010 (1)
• 0100 (1)

0 marks if the response is not 8-bit binary.

Ignore a carry shown beyond the eighth bit.

Award one mark for:

• overflow (error) (1)

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.

Indicative content

Machine independence

• A high-level language is machine independent, so the same source code can be run on different types of computer with few or no changes.
• The company can write the program once and sell it to users with different computers, without rewriting the code for each type of computer.
• Only one version of the program needs to be written and maintained, so development takes the company less time.

Processor specificity

• A low-level language is processor-specific, so a program written for one processor will not run on a different processor without being rewritten.
• Assembly language instructions depend on the instruction set of the particular processor, so the company would need a separate version of the program for each type of computer.
• Writing a separate low-level version for every type of computer would take the company much longer than writing one high-level program.
• Low-level code gives direct control of the hardware of one processor, so it is better suited to device drivers than to a program that must run on many different computers.

Translation

• High-level source code is translated for each type of computer by a compiler or an interpreter, so one version of the source code is enough for all the users.
• Assembly language is translated into machine code by an assembler, and the assembler produces machine code for one specific processor only.
• Machine code is already in a form that one particular processor can execute directly, but the same machine code will not run on a different processor.
• Each high-level statement translates into several machine code instructions, so the programmer does not need to know the instruction set of the processor.

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 both high-level machine independence and low-level processor specificity, with the effect on the company's decision.
• Do not award low-level language, assembly language or machine code as portable, or 'high-level languages are written in English/like English' as a reason for machine independence.