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June 2025 OCR: A Level Computer Science
H446/01 Computer Systems – Merged Question
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What is Von Neumann architecture? - CORRECT ANSWER A computer architecture design where the CPU, memory, and input/output devices are connected through a single bus, allowing both data and instructions to be stored in the same memory space. How does Harvard architecture differ from Von Neumann architecture? - CORRECT ANSWER Harvard architecture has separate memory storage for instructions and data, allowing simultaneous access, while Von Neumann architecture uses a single memory space for both. What are two features of a replacement processor that would increase performance? - CORRECT ANSWER 1. Higher clock speed (e.g., 3.0 GHz) for faster processing. 2. Increased number of cores (e.g., quad-core) for better multitasking capabilities. What is pipelining? - CORRECT ANSWER A technique used in processors where multiple instruction phases (fetch, decode, execute) are overlapped to improve instruction throughput and overall performance. What is one benefit of using a processor that allows pipelining? - CORRECT ANSWER Pipelining increases the instruction throughput, allowing the processor to execute more instructions in a given time, thus improving overall system performance. How is the accumulator used during the Fetch-Decode-Execute cycle? - CORRECT ANSWER The accumulator temporarily holds the results of arithmetic and logic operations performed by the CPU during the execution phase.
How is the program counter used during the Fetch-Decode-Execute cycle? - CORRECT ANSWER The program counter holds the memory address of the next instruction to be fetched and is incremented after each instruction fetch. What is the purpose of the Little Man Computer (LMC) program? - CORRECT ANSWER The LMC program calculates and outputs the total amount of donations received by the charity, potentially adding a bonus based on the donation amount. What is the output for an input of 10 in the LMC program? - CORRECT ANSWER The output will be 10, as there is no bonus added for amounts less than 100. What is the output for an input of 50 in the LMC program? - CORRECT ANSWER The output will be 50, as there is no bonus added for amounts less than 100. What is the output for an input of 120 in the LMC program? - CORRECT ANSWER The output will be 140, as a bonus of 20 is added to the total of 120. What is the purpose of the 'DAT' instruction in LMC? - CORRECT ANSWER The 'DAT' instruction is used to define data values that can be used in the program, such as constants for calculations. What does the 'INP' instruction do in LMC? - CORRECT ANSWER The 'INP' instruction prompts the user to input a value, which is then stored in a designated memory location. What does the 'OUT' instruction do in LMC? - CORRECT ANSWER The 'OUT' instruction outputs the value stored in the accumulator to the user. What is the role of the 'STA' instruction in LMC? - CORRECT ANSWER The 'STA' instruction stores the value from the accumulator into a specified memory location. What is the role of the 'LDA' instruction in LMC? - CORRECT ANSWER The 'LDA' instruction loads a value from a specified memory location into the accumulator.
Name three registers used during the Fetch-Decode-Execute cycle. - CORRECT ANSWER 1. Program Counter (PC) - holds the address of the next instruction to be executed. 2. Instruction Register (IR) - holds the current instruction being executed. 3. Accumulator (ACC) - stores intermediate results of arithmetic and logic operations. What is the suitability of CISC processors for mobile devices? - CORRECT ANSWER CISC processors may not be as suitable for mobile devices due to their higher power consumption and complexity, which can lead to reduced battery life and performance. What is the suitability of RISC processors for mobile devices? - CORRECT ANSWER RISC processors are often more suitable for mobile devices due to their lower power consumption, simpler design, and ability to execute instructions more quickly, which enhances battery life and performance. What is the main difference between CISC and RISC? - CORRECT ANSWER The main difference is that CISC processors have a complex set of instructions that can execute multiple tasks per instruction, while RISC processors have a simplified set of instructions that focus on executing a single task per instruction efficiently. What is a primary key? - CORRECT ANSWER A primary key is a unique identifier for a record in a database table, ensuring that no two records can have the same primary key value. What is a foreign key? - CORRECT ANSWER A foreign key is a field in one table that uniquely identifies a row of another table, establishing a relationship between the two tables. What is the foreign key in the database? - CORRECT ANSWER The foreign key is 'PackageType' in the 'Membership' table. What is the data type of the CostPerMonth(£) field? - CORRECT ANSWER The data type of the CostPerMonth(£) field is 'Currency' or 'Decimal'. What field could be stored using a Boolean data type? - CORRECT ANSWER The field 'Adverts' could be stored using a Boolean data type.
What does the Adverts field indicate? - CORRECT ANSWER The Adverts field indicates whether customers will be shown adverts, with 'true' meaning they will see adverts and 'false' meaning they will not. What is SQL? - CORRECT ANSWER SQL (Structured Query Language) is a programming language used to manage and manipulate relational databases. What SQL query returns the Username and FirstName for customers who see adverts? - CORRECT ANSWER SELECT Username, FirstName FROM Membership WHERE Adverts = true; What is one method of capturing a new customer's personal data? - CORRECT ANSWER One method is using an online registration form, which is suitable because it allows customers to easily input their information directly into the database. What is a suitable method for exchanging data with other computer systems? - CORRECT ANSWER 1. API (Application Programming Interface) - allows different systems to communicate and exchange data. 2. File Transfer Protocol (FTP) - enables the transfer of files between systems. What does ACID stand for? - CORRECT ANSWER ACID stands for Atomicity, Consistency, Isolation, and Durability, which are properties that guarantee reliable processing of database transactions. What does it mean for a transaction to be durable? - CORRECT ANSWER Durability means that once a transaction has been committed, it will remain so, even in the event of a system failure. How can durability be achieved for a completed transaction? - CORRECT ANSWER Durability can be achieved by writing the transaction data to a non-volatile storage medium, such as a hard drive. What is record locking? - CORRECT ANSWER Record locking is a mechanism that prevents multiple transactions from modifying the same record simultaneously, ensuring the isolation property of ACID. How does record locking ensure isolation in transactions? - CORRECT ANSWER Record locking ensures isolation by preventing other transactions from accessing a record that is currently being modified, thus avoiding conflicts and ensuring data integrity.
What does the constructor method do in a class? - CORRECT ANSWER The constructor method initializes the attributes of a class when an object is created, often setting default values. What is the purpose of the updateviews() method? - CORRECT ANSWER The updateviews() method is used to increase the number of views for a video by one each time it is called. How do you convert hexadecimal B7E to binary? - CORRECT ANSWER The hexadecimal value B7E converts to binary as 101101111110. How do you convert the binary number 110010101 to denary? - CORRECT ANSWER The binary number 110010101 represents the denary number - 53 when using sign and magnitude representation. What is two's complement? - CORRECT ANSWER Two's complement is a method for representing signed integers in binary, allowing for easy addition and subtraction of both positive and negative numbers. How do you perform binary subtraction using two's complement? - CORRECT ANSWER To perform binary subtraction using two's complement, convert the number to be subtracted into its two's complement form and then add it to the other number. What is a normalized floating point number? - CORRECT ANSWER A normalized floating point number is represented in a way that maximizes precision by ensuring that the leading digit of the mantissa is non- zero. What is the denary version of the normalized floating point number 1010 1110? - CORRECT ANSWER To convert the normalized floating point number 1010 1110 to denary, separate the mantissa (1010) and exponent (1110). The mantissa in decimal is 10, and the exponent in decimal (two's complement) is - 2. The denary value is calculated as 10 * 2^(-2) = 10 / 4 = 2.5. What does it mean for a floating point number to be not normalized? - CORRECT ANSWER A floating point number is not normalized if the mantissa does not have a leading non-zero digit, which can lead to less precision.
What is Artificial Intelligence (AI)? - CORRECT ANSWER Artificial Intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems, including learning, reasoning, and self-correction. How can AI inherit biases from programmers? - CORRECT ANSWER AI can inherit biases from programmers through biased training data, flawed algorithms, or the subjective decisions made during the development process. What are examples of AI being affected by bias? - CORRECT ANSWER Examples include facial recognition systems misidentifying individuals based on race, hiring algorithms favoring certain demographics, and predictive policing tools disproportionately targeting specific communities. What measures can be taken to prevent bias in AI? - CORRECT ANSWER Measures include using diverse and representative training datasets, implementing bias detection tools, conducting regular audits of AI systems, and involving multidisciplinary teams in AI development. What is the significance of the mantissa in floating point representation? - CORRECT ANSWER The mantissa represents the significant digits of the number and determines the precision of the floating point representation. What is the role of the exponent in floating point representation? - CORRECT ANSWER The exponent determines the scale or range of the number, allowing for representation of very large or very small values. What is the purpose of using a 6-bit mantissa and 3-bit exponent? - CORRECT ANSWER Using a 6-bit mantissa and a 3-bit exponent allows for a balance between precision and range in floating point representation. What is the maximum value represented by a normalized floating point number with 6 bits for the mantissa and 3 bits for the exponent? - CORRECT ANSWER The maximum value would occur with the mantissa set to its maximum normalized value and the exponent set to its maximum value, which would be calculated based on the specific representation rules.
What are the consequences of using biased AI systems? - CORRECT ANSWER Consequences can include discrimination, loss of trust in technology, and negative impacts on affected individuals and communities. What is the purpose of using two's complement for the exponent? - CORRECT ANSWER Using two's complement for the exponent allows for a more efficient representation of both positive and negative exponents in floating point numbers. What is the significance of the leading digit in the mantissa? - CORRECT ANSWER The leading digit in the mantissa is significant because it determines the precision and range of the floating point representation. What is the output of print(mystery(10,20))? - CORRECT ANSWER The output is 30. What is the output of print(mystery(0,70))? - CORRECT ANSWER The output is 70. What is the output of print(mystery(45,55))? - CORRECT ANSWER The output is 55. What is the purpose of a translator? - CORRECT ANSWER The purpose of a translator is to convert high- level programming code into machine code that can be executed by a computer. What is one difference between a compiler and an interpreter? - CORRECT ANSWER A compiler translates the entire program into machine code before execution, while an interpreter translates the program line-by-line during execution. What is another difference between a compiler and an interpreter? - CORRECT ANSWER Compilers produce an object code file that can be executed later, while interpreters execute the code directly without producing an intermediate file. What happens during lexical analysis? - CORRECT ANSWER During lexical analysis, comments and whitespace are removed, and keywords are replaced with tokens.
What happens during syntax analysis? - CORRECT ANSWER During syntax analysis, an abstract syntax tree is built and a symbol table is created for variables. What is the purpose of code generation? - CORRECT ANSWER The purpose of code generation is to create object code that can be executed by the computer. What is the purpose of code optimization? - CORRECT ANSWER The purpose of code optimization is to improve the performance and efficiency of the code by reducing its size or execution time. What is the function of asc() in programming? - CORRECT ANSWER The asc() function takes a character as input and returns its ASCII value. What is one similarity between ASCII and Unicode? - CORRECT ANSWER Both ASCII and Unicode are character encoding standards used to represent text in computers. What is one difference between ASCII and Unicode? - CORRECT ANSWER ASCII uses 7 bits to represent characters, allowing for 128 unique symbols, while Unicode uses multiple bytes to represent a much larger set of characters. What is another difference between ASCII and Unicode? - CORRECT ANSWER ASCII primarily supports English characters, while Unicode supports characters from multiple languages and scripts. What is the spiral model in software development? - CORRECT ANSWER The spiral model is a software development methodology that combines iterative development with the systematic risk analysis of each iteration. What is the waterfall model in software development? - CORRECT ANSWER The waterfall model is a linear and sequential approach to software development where each phase must be completed before the next begins. What is a benefit of the spiral model? - CORRECT ANSWER A benefit of the spiral model is that it allows for incremental development and frequent reassessment of risks.
What is an encrypted messaging program? - CORRECT ANSWER A software application that secures messages through encryption, ensuring that only intended recipients can read the content. What is the TCP/IP stack? - CORRECT ANSWER A set of communication protocols used for the internet and similar networks, consisting of layers that handle different aspects of data transmission. What happens at the application layer of the TCP/IP stack? - CORRECT ANSWER At the application layer, user applications interact with the network, preparing data for transmission and managing communication protocols, such as HTTP or FTP. What is the link layer in TCP/IP? - CORRECT ANSWER The link layer, also known as the network interface layer, network access layer, or simply the network layer, is responsible for the physical transmission of data over a network. It handles the protocols and technologies that connect devices to the network. What happens at the link layer when using a program? - CORRECT ANSWER At the link layer, the program interacts with the hardware to send and receive data frames. It manages the addressing of devices on the local network, error detection, and the framing of data packets for transmission. What is the role of the network interface layer? - CORRECT ANSWER The network interface layer facilitates communication between the network layer and the physical network. It prepares data for transmission and ensures that it is properly formatted for the specific network technology being used. What is data framing? - CORRECT ANSWER Data framing is the process of encapsulating data packets into frames for transmission over a network. Each frame contains a header with addressing information and a trailer for error checking. What is error detection in the link layer? - CORRECT ANSWER Error detection in the link layer involves techniques to identify errors that may occur during data transmission. Common methods include checksums and cyclic redundancy checks (CRC). What is the significance of MAC addresses? - CORRECT ANSWER MAC addresses are unique identifiers assigned to network interfaces for communication on the physical network. They are used to ensure that data frames are delivered to the correct device.
What protocols operate at the link layer? - CORRECT ANSWER Common protocols that operate at the link layer include Ethernet, Wi-Fi (IEEE 802.11), and Point-to-Point Protocol (PPP). What is the function of the physical layer in relation to the link layer? - CORRECT ANSWER The physical layer is responsible for the actual transmission of raw bitstreams over a physical medium, while the link layer manages the framing and addressing of these bits into data frames. What is the difference between the link layer and the network layer? - CORRECT ANSWER The link layer focuses on local network communication and data framing, while the network layer is responsible for routing data across multiple networks and managing logical addressing (e.g., IP addresses). How does the link layer handle multiple access? - CORRECT ANSWER The link layer employs multiple access protocols, such as Carrier Sense Multiple Access (CSMA) and Token Ring, to manage how multiple devices share the same communication medium. What is the purpose of a network switch? - CORRECT ANSWER A network switch operates at the link layer to connect devices within a local area network (LAN), forwarding data frames based on MAC addresses to the appropriate destination. What is a data link protocol? - CORRECT ANSWER A data link protocol defines the rules for data transmission over a specific physical medium, including how frames are constructed, addressed, and checked for errors. What is the role of a network interface card (NIC)? - CORRECT ANSWER A network interface card (NIC) is a hardware component that connects a computer to a network, providing the necessary interface for data transmission and reception at the link layer. What is the significance of the frame header? - CORRECT ANSWER The frame header contains essential information such as source and destination MAC addresses, frame type, and control information necessary for the proper handling of the frame. What is the purpose of flow control in the link layer? - CORRECT ANSWER Flow control mechanisms in the link layer manage the rate of data transmission between devices to prevent overwhelming a receiving device and ensure smooth communication.
What is OCR? - CORRECT ANSWER OCR stands for Oxford Cambridge and RSA, an organization that provides educational assessments and qualifications. What is the purpose of the OCR Copyright Team? - CORRECT ANSWER The OCR Copyright Team seeks permission to reproduce third-party content used in assessment materials and addresses any copyright issues. Where can you find the OCR Copyright Acknowledgements Booklet? - CORRECT ANSWER The OCR Copyright Acknowledgements Booklet is available for download on the OCR public website after the live examination series. What should you do if you have queries about OCR copyright? - CORRECT ANSWER For queries or further information, you can contact the OCR Copyright Team at their office in Cambridge. What does OCR do if they fail to acknowledge third-party content? - CORRECT ANSWER If OCR unwittingly fails to acknowledge or clear third-party content, they will correct the mistake at the earliest opportunity. What is the relationship between OCR and the University of Cambridge? - CORRECT ANSWER OCR is part of Camalphanumeric - CORRECT ANSWER collective name for letters, digits, symbols analogue signal - CORRECT ANSWER a continuous signal which can't be processed by a computer argument - CORRECT ANSWER a value that a parameter of a subprogram actually takes ALU - CORRECT ANSWER part of CPU that carries out arithmetic and Boolean operations array - CORRECT ANSWER data structure where all data is stored and defined under one variable name ASCII - CORRECT ANSWER A 7-bit character set consisting of 128 characters assembler - CORRECT ANSWER a program that turns assembly language into machine code
assembly language - CORRECT ANSWER low-level langauge authentication - CORRECT ANSWER a process for checking user identity binary - CORRECT ANSWER a counting system using base-2 consisting of 0s and 1s binary shift - CORRECT ANSWER moving the bits in a binary number left or right and filling gaps with 0s BIOS - CORRECT ANSWER Basic Input Output System bitmap image - CORRECT ANSWER a graphic made up of pixels bit - CORRECT ANSWER a binary digit either 0 or 1 bit rate - CORRECT ANSWER number of bits used per second of sampled audio breakpoint - CORRECT ANSWER a programming tool used to halt a program at a specific place byte - CORRECT ANSWER 8 bits casting - CORRECT ANSWER a way of changing from one data type to another character - CORRECT ANSWER a single alphanumeric symbol code editor - CORRECT ANSWER part of an IDE where you write and edit your source code colour depth - CORRECT ANSWER the number of bits used for each pixel in an image file
error diagnostics - CORRECT ANSWER information about an error once it is detected extended ASCII - CORRECT ANSWER an 8-bit character set consisting of 256 characters extreme data - CORRECT ANSWER Test data on the boundary of what a program will accept field - CORRECT ANSWER A column of a database used to store a category of data file handling - CORRECT ANSWER reading from and writing to external files file sharing - CORRECT ANSWER copying files between services of work final testing - CORRECT ANSWER when the testing stage of the software developing cycle is only done once to check the software. flat-file database - CORRECT ANSWER A database that only contains one table of data flow diagram - CORRECT ANSWER a graphical way of showing an algorithm FOR loop - CORRECT ANSWER A type of count-controlled iteration statement functionality testing - CORRECT ANSWER A type of testing that assesses how well a program meets the requirements function - CORRECT ANSWER A sub program that takes parameters and returns a value Gigabyte - CORRECT ANSWER 1000 megabytes global variable - CORRECT ANSWER a variable available throughout the whole program
GPU - CORRECT ANSWER A circuit for handling the processing of graphics and images GUI - CORRECT ANSWER Allows the user to interact with the computer in a visual and intuitive way GUI builder - CORRECT ANSWER an IDE tool for giving a program a graphical user interface hexadecimal - CORRECT ANSWER a counting system using base-16 consisting of 0-9 digits and letters a-f high-level language - CORRECT ANSWER A programming language like C++ or Java IF statement - CORRECT ANSWER type of selection statement indentation - CORRECT ANSWER Spaces put at the beginning of a line of code to help show a programs structure input sanitation - CORRECT ANSWER removing unwanted characters from an input input validation - CORRECT ANSWER Checking that an input meets a certain criteria integer - CORRECT ANSWER A numerical data type for whole numbers interpreter - CORRECT ANSWER A translator that turns source code into machine code iteration statement - CORRECT ANSWER A statement which make a program repeat a series of instructions iterative testing - CORRECT ANSWER Repeated testing done during the development of a program
