JAMB UTME - Computer Studies - 2025

Computers are grouped into generations based on the core technology used to build them, and this technology strongly affected their cost, size, and reliability.

First generation computers were built using vacuum tubes. Vacuum tubes consumed enormous amounts of electrical power, generated a great deal of heat, required constant cooling, and failed frequently, which meant they needed continuous maintenance and replacement parts. All of this made first generation computers extremely expensive to keep running.

Later generations moved to transistors (second generation), integrated circuits (third generation), and microprocessors (fourth generation), each of these advances reduced power consumption, heat output, size, and the frequency of failures, which steadily lowered running costs compared to the vacuum-tube-based first generation machines.

Exam tip: link vacuum tubes directly to the first generation, and remember that their high power use, heat, and failure rate is exactly why running them was so expensive.

The central processing unit is made up of several parts that work together, but only one of them is responsible for directing the others. The arithmetic and logic unit performs calculations and comparisons, and the memory unit stores data, but neither of these decides when or how the various components should act.

That coordinating role belongs to the control unit. It generates the timing and control signals that tell the input unit when to supply data, the arithmetic and logic unit when to perform an operation, the memory unit when to read or write data, and the output unit when to display results. By managing this flow of instructions and resources across every other unit, the control unit acts as the coordinator of the entire processor.

There is no separate "coordinating unit" in standard computer architecture; whenever a question asks which part coordinates or manages the CPU's other components, the answer is the control unit.

A server or network can only handle a limited number of requests at once. An attack that deliberately overwhelms that capacity by sending far more traffic or connection requests than the system can process is designed to make the service unavailable to the genuine users it is meant to serve. This is the defining feature of a denial-of-service attack: the goal is disruption of availability, not theft of data.

This is different from attacks that aim to steal or manipulate information. A man-in-the-middle attack secretly intercepts communication between two parties to read or alter it. A phishing attack tricks a user into revealing personal information, usually through a fake message or website. An SQL injection attack inserts malicious code into a database query to access or corrupt stored data. None of these three works by flooding a system with excessive traffic; they rely on deception or exploiting how data is processed, not on overwhelming capacity.

Examination reminder: when a question describes an attack that floods a system to stop legitimate access, look for "denial of service" language such as "unavailable," "overwhelmed," or "flooded."

Different networks often use different addressing schemes, protocols, or data formats, so a device is needed to translate between them whenever data must travel from one network to another. The device designed for exactly this role sits at the boundary between two networks and converts data from the format or protocol used on one network into the format required by the other, acting as an entry and exit point that allows devices on separate networks to communicate with each other.

A device used to connect and switch between two communication lines manually is a much simpler switching tool and does not perform the protocol translation needed to join two different networks. A device that converts digital data into signals suitable for transmission over a telephone line, and back again, connects a single computer or network to a communication line, but it does not translate between two different networks' addressing or protocol standards. A device that combines multiple separate signals into one shared communication channel, so they can be transmitted together and later separated at the receiving end, is concerned with sharing transmission capacity, not with enabling communication between two distinct networks.

The keyword to associate with cross-network communication is the device sitting at the "gate" between two different networks, translating data so that devices on each side can understand one another despite using different network standards.

The hexadecimal number system is a base-16 numbering system, meaning it uses sixteen distinct symbols to represent values. Since the ordinary decimal digits 0 to 9 only provide ten symbols, hexadecimal borrows six letters of the alphabet to represent the remaining values.

Counting upward from 9, the next value (equivalent to decimal 10) is represented by the letter A, decimal 11 by B, decimal 12 by C, decimal 13 by D, decimal 14 by E, and decimal 15 by F. This gives the complete set of sixteen hexadecimal digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F. The sequence therefore runs from 0-9 and A-F, which completes the sixteen required symbols.

A letter such as D or E marks only the fourth or fifth letter in the sequence, not the last one, so stopping there would leave the system with fewer than sixteen symbols. Only F closes the full run from A through F.

Exam tip: remember that hexadecimal always has exactly sixteen symbols, so if you are ever unsure where the letter sequence ends, count six letters starting from A; the sixth letter, F, is always the final hexadecimal digit.

This question is asking you to separate a general thinking skill from formally defined software development models.

SDLC, the waterfall model, and the prototype model are all specific, named approaches used in problem solving within software development, each with defined stages describing how a solution is planned, built, and delivered. Critical thinking, on the other hand, is a general mental skill, the ability to analyse information logically and evaluate ideas objectively, it is not a structured, named model with defined stages that guides how a software problem is solved from start to finish.

Because critical thinking describes a way of reasoning rather than a formal development model, it does not belong in the same category as SDLC, waterfall, and prototype, which are all concrete frameworks with clearly defined steps.

Exam tip: when a question lists several named development frameworks alongside a general skill or ability, the general skill is usually the odd one out, since it lacks the defined structure that makes something a "model."

Computer networks are classified by the size of the area they cover. A network confined to a single building, such as one office, one school building, or one home, is called a Local Area Network (LAN). It connects computers and devices that are close together, usually using cables or a local wireless router.

A Campus Area Network (CAN) covers several buildings on one site, larger than a single office. A Metropolitan Area Network (MAN) spans a city, and a Wide Area Network (WAN) spans a country or the entire globe, connecting many separate LANs together, for example the internet. Since the question specifies a network contained inside one office building, the scale matches a LAN, not the larger categories.

Exam takeaway: rank the network types by geographic scale from smallest to largest, LAN, CAN, MAN, WAN, and match the scenario described to the size that fits.

File security refers to the deliberate measures put in place to protect stored data from loss, corruption, or unauthorised access. Genuine file-security methods include restricting access with a password, keeping duplicate copies through backup so data can be recovered if the original is damaged, and running anti-virus software to detect and remove malicious programs that could destroy or steal data.

Hacking is the opposite of a security method. It is the unauthorised act of breaking into a computer system to access, alter, or steal data, which is precisely the threat that passwords, backups, and anti-virus software are designed to guard against. Because it attacks file security rather than protecting it, hacking cannot be classed alongside the other three items.

When a question asks which item does not belong with a set of protective measures, check whether that item is itself a threat rather than a defence; a threat can never be listed as a security method.

The term "booting" comes from the phrase "pulling yourself up by your bootstraps", describing how a computer, on power-up, must load its own operating system into memory before it can do anything else, without any operating system already running to help it.

Booting therefore refers specifically to the process of starting a computer: the system runs its initial hardware checks, then loads the operating system from storage into memory so that the machine becomes ready for use. This is the meaning that matches the everyday word "starting".

"Restarting" describes shutting down and booting again, which is a related but more specific event than the general act of starting up. "Loading" and "running" are broader terms that can apply to any program, not specifically to the unique process of bringing a computer to life from a powered-off state.

Examination reminder: reserve "booting" for the very first startup sequence of a computer, and use "rebooting" only when specifically describing a restart after the system was already running.

PowerPoint offers several ways to view a presentation, each suited to a different task. Slide Sorter view shows small thumbnails of every slide for reordering them, Presenter view is used while actually delivering the presentation and shows notes only to the speaker on a separate screen, and Reading view displays the slides full-screen for reviewing content without editing tools.

To add speaker notes directly onto a slide, the correct approach is to open the View tab and select Notes Page. This view displays each slide with a text box beneath it specifically for typing notes that the presenter can refer to, and clicking into that area allows the notes to be typed or edited directly.

The distinction to hold onto is that Presenter view displays notes that already exist while presenting, whereas Notes Page view is where those notes are actually written and edited beforehand.

This question is testing whether you know the wide range of things computers are used for today, rather than a single narrow technical fact.

Computers are routinely used for entertainment (games, streaming video and music), for accessing and processing information (research, storing records, calculations), and for social media (connecting with people, sharing posts and messages online). Since every one of these listed activities is, in fact, something computers are commonly used for, there is no option among them that correctly names something computers are not used for.

Because entertainment, information, and social media are all genuine, everyday uses of a computer, the only option consistent with the facts is the one that rejects all three as the exception being asked for.

Exam tip: on "which is NOT" questions, always check whether every listed item actually fits the category before picking one, if they all fit, the correct choice is the one that says none of them is the exception.

A word processor is application software designed for creating and handling text documents. Its core functions cover the whole life cycle of a document, from first creating it to producing a final copy.

Users can write new text into a document, go back and edit that text by inserting, deleting, or reformatting words and paragraphs, and then print the finished document onto paper. These are not separate, competing capabilities; they are all standard, everyday functions built into any word processor such as Microsoft Word.

Because writing, editing, and printing are all genuine and commonly used features of a word processor, the complete and accurate answer covers all three rather than singling out just one.

Exam takeaway: when a question lists several correct, non-conflicting capabilities of the same software and one choice claims all of these are true, check whether every listed capability genuinely holds before ruling it out.

Booting is the process of starting up a computer and loading its operating system into memory. The type of boot depends on the state the computer was in before it started: a warm boot or reboot happens when a computer that is already switched on is restarted, either through software or a reset button, without disconnecting its power supply.

Starting a computer from a completely powered-down state, where it had no power running through it beforehand, is called a cold boot. During a cold boot, the system must run its full startup checks from scratch, including the power-on self-test, since none of its circuits were already active.

Distinguish the two by the starting condition of the machine: powered off before starting means a cold boot, while restarting a machine that was already on means a warm boot.

An algorithm is a step-by-step set of instructions for solving a problem, and it can be represented in more than one way: written out in structured, code-like sentences, or represented visually. The visual, diagrammatic method uses standard shapes, such as an oval for start and end points, a rectangle for a process step, and a diamond for a decision point, all connected by arrows that show the order in which steps are carried out. This diagrammatic representation of an algorithm is called a flowchart, and it lets someone follow the logic of an algorithm visually without reading detailed written instructions.

Pseudocode also represents an algorithm's logic, but it does so through structured, plain-language statements written in lines of text resembling programming code, not through shapes and diagrams. Code refers to the actual instructions written in a specific programming language that a computer can execute, which is a textual, executable representation rather than a diagrammatic one. Graphics is simply a general term for visual images and does not refer to any structured method of representing an algorithm's logical steps.

When a question specifically asks for the "diagrammatic" representation of an algorithm, that phrasing should immediately point to flowcharts, since pseudocode and code are both text-based rather than diagram-based.

Keyboards include several special-purpose keys that change how ordinary letter keys behave rather than typing a character themselves. The Caps Lock key is one of these.

Pressing Caps Lock toggles the keyboard between typing letters in upper case, capital letters, and typing them in lower case, small letters. Once activated, every letter key pressed produces a capital letter until Caps Lock is pressed again to switch back.

This is distinct from moving through pages, deleting files, or inserting spaces, which are handled by other dedicated keys such as Page Up or Page Down, the Delete key, and the Space bar respectively. Caps Lock's sole function is the upper case and lower case switch.

Exam takeaway: remember Caps Lock as a toggle switch for letter case, separate from navigation, deletion, or spacing functions on the keyboard.

Binary Coded Decimal (BCD) is a method of representing decimal numbers in binary form by encoding each individual decimal digit (0-9) separately, rather than converting the whole number to a single binary value.

Since a decimal digit can range from 0 to 9, at least four binary bits are needed to represent it, because \(2^4 = 16\) possible combinations are enough to cover all ten digit values (0000 to 1001 are used, while 1010 to 1111 are unused). A group of exactly four bits is called a nibble, which is half of a standard 8-bit byte.

So in BCD, every decimal digit of a number is stored as its own 4-bit nibble. For example, the decimal number 47 would be stored as 0100 (representing 4) followed by 0111 (representing 7), two nibbles placed side by side rather than one combined binary value.

A common confusion is mixing this up with a byte, which is 8 bits and normally holds two BCD digits (one nibble each), or with a single bit, which can only represent two states (0 or 1) and cannot encode a full decimal digit on its own.

Exam tip: whenever a question links "4 bits" with "one decimal digit," the term being tested is nibble, not byte or bit.

A Java program is not translated straight from its human-readable source code into machine language. It first passes through a Java compiler, which converts the source code into an intermediate form designed to run on the Java Virtual Machine (JVM) rather than directly on any specific processor. This intermediate form is called byte code.

The Java interpreter, working as part of the JVM, then reads this byte code and translates it, instruction by instruction, into the machine language that the actual computer processor can execute. This two-step process (source code to byte code by the compiler, then byte code to machine language by the interpreter) is what allows the same compiled Java program to run on different types of computers without being rewritten, since only the byte code needs to be produced once. A nibble, a bit, and high level language describe unrelated units or the original source form, not the intermediate form the interpreter actually works from.

Exam takeaway: remember the Java pipeline in order: high-level source code is compiled into byte code, and the interpreter (JVM) then converts that byte code into machine language for execution.

Communication channels are classified by the direction in which data can travel between two devices.

Simplex mode allows data to travel in only one direction at all times; one device can only transmit and the other can only receive, with no possibility of the roles reversing. A common example is a radio broadcast, where the signal flows from the transmitter to the receiver and never the other way.

The other modes all allow communication in both directions, differing only in timing. Half duplex mode allows data to travel in both directions, but only one direction at a time, similar to a walkie-talkie where users take turns speaking. Duplex and full duplex mode (these refer to the same concept) allow data to travel in both directions simultaneously, as happens in an ordinary telephone conversation.

When a question asks for a channel that sends data in one direction only, with no reverse flow at any time, that description matches simplex mode specifically, since every other mode listed permits two-way communication.

Logic gates produce an output based on fixed rules applied to their inputs. An AND gate only outputs HIGH when every input is HIGH, a NOT gate simply inverts a single input, and a NOR gate outputs HIGH only when all of its inputs are LOW, the opposite behaviour of what is being described.

The gate that produces a HIGH output whenever at least one of its inputs is HIGH is the OR gate. Its truth table shows that the only way to get a LOW output is for every single input to be LOW at the same time; as soon as one or more inputs become HIGH, the output switches to HIGH.

Remember the OR gate by the phrase "any one is enough": if any single input is HIGH, the output is HIGH.

A spreadsheet is a document organised into rows and columns of cells, used for storing numbers, performing calculations, and building charts from data. The application built specifically for this purpose provides ready-made formulas, functions, and cell-referencing tools that let a user calculate totals, averages, and other results automatically as data changes.

A presentation application is designed for building slideshows made up of text, images, and animations for delivering talks, not for organising data in a row-and-column grid. An early word-processing program built for Apple computers, along with a modern word-processing application, are both designed for typing, formatting, and editing text documents such as letters and reports; while a word processor can display a simple table, it lacks the calculation engine, cell referencing, and formula system that define a true spreadsheet.

The defining feature to look for in this kind of question is the presence of a grid of cells combined with built-in formulas for automatic calculation, since that combination is unique to spreadsheet software among the applications listed.

Program development is a step-by-step process: understanding the problem, designing a solution, writing code, and testing it. Each step depends on careful, methodical work, because a mistake made early, such as a misread requirement or a rushed line of code, tends to carry forward and multiply through later stages.

Being stable, steady, and patient keeps a programmer working carefully through each step rather than rushing or skipping checks, which directly reduces the likelihood of making errors such as logic mistakes, typing errors, or missed requirements. A calm, methodical approach also makes it easier to spot a small error before it becomes a bigger problem buried deep in the program.

This is not about avoiding debugging tools or slowing the work down for its own sake; patience is valuable specifically because it prevents the errors that would otherwise need to be found and fixed later, often at greater cost in time.

Booting is the process by which a computer starts up and becomes ready for use. When power is switched on, the hardware first runs a small built-in startup routine, but that routine's main job is to locate and load a larger program that will manage the whole system from that point onward.

That larger program is the operating system, OS, which controls hardware resources, manages files, and provides the environment in which other software, including compilers, assemblers, and loaders, can run. Without an operating system installed and loadable, the startup process has nothing to hand control over to, so the computer cannot complete booting into a usable state.

Compilers, assemblers, and loaders are useful programs for translating and preparing other software, but none of them manage the overall running of the machine the way an operating system does, and none of them can substitute for its absence during boot.

Exam takeaway: booting is really the process of loading the operating system, so the operating system is the one component that is indispensable for it to succeed.

Programming languages are grouped into levels based on how close they are to the way a computer's hardware actually operates. A high-level language uses English-like keywords and structures (such as loops, functions, and readable variable names) that are far removed from the binary instructions a processor executes, which makes such languages easier for humans to read, write, and maintain. A low-level language, by contrast, is written in instructions that closely mirror the processor's own operations, using short mnemonic codes tied directly to specific hardware registers and memory addresses.

Among the options, the language built from short mnemonics that map almost one-to-one onto a processor's machine instructions is a low-level language: it requires a programmer to think in terms of registers, memory addresses, and individual CPU operations rather than abstract logic. The other three languages listed all use readable, structured syntax with built-in libraries and abstractions that let a programmer describe what should happen without worrying about the underlying hardware, which is exactly what defines a high-level language.

A common misconception is that "low-level" means simple or beginner-friendly; it actually means low-level in terms of abstraction from hardware, and such languages are typically harder to learn because they demand precise control over the machine itself.

Just as social situations in the physical world have accepted rules of polite behaviour, online communication has its own accepted set of behavioural rules that help interactions stay respectful and orderly.

The specific term for etiquette followed while working or communicating online is netiquette, a blend of the words "network" and "etiquette". It covers practices such as respecting others' privacy, avoiding offensive language, and not spamming or misusing shared online spaces.

The idea that "anything goes" as long as a person remains anonymous is the opposite of etiquette; it describes a lack of accountability rather than a code of good conduct. "Netflix" is a streaming entertainment service and has no connection to behavioural rules online. "Piracy" refers to the illegal copying or distribution of protected content, which is a specific offence, not a general code of online conduct.

Notice how the word netiquette is built by combining "net", short for network, with "etiquette", which makes it easy to recall its meaning directly from its spelling.

Before any mechanical or electronic calculating devices existed, people needed a way to keep track of numbers and perform arithmetic. The earliest such device, dating back thousands of years to ancient civilisations, is a manual counting frame consisting of a wooden or metal frame with rods holding movable beads. By sliding these beads into different positions, a user could add, subtract, and perform other simple calculations. Because it was the very first tool humans built specifically to compute, it is recognised as the first computing machine ever invented.

The other options came much later and depended on more advanced design ideas. A device made of two logarithmic scales that slide against each other to multiply and divide numbers was developed in the 17th century, long after the counting frame was already in wide use. A set of rods marked with multiplication tables, used to simplify multiplication and division by manual lookup, was invented in the early 1600s, and a mechanical device using gears to perform addition and subtraction was built shortly afterward, also in the 17th century. All three of these tools represent later refinements in calculating technology, not the original invention.

When a question asks for the "first" computing device, look for the tool with the oldest documented history rather than the most sophisticated mechanism; simplicity and antiquity, not complexity, mark the starting point of computing history.

Several keys on a keyboard perform editing actions rather than inserting a new character, and each has a distinct, specific role during text entry.

The backspace key removes the character immediately to the left of the cursor each time it is pressed, which is the standard way to delete text while typing. The arrow keys only move the cursor position without removing anything, the enter key starts a new line or confirms an action, and the escape key cancels an operation or closes a dialog rather than deleting characters.

Because deleting typed text specifically requires removing characters one at a time from where the cursor sits, only the backspace key performs that function among the options given.

Exam takeaway: separate keys that move the cursor, like the arrow keys, from keys that remove content, like backspace, since students often confuse navigation keys with editing keys.

Navigating a computer means moving around the screen, selecting items, and controlling the position of the pointer or text-entry point. The cursor is the on-screen marker that shows the current position; the keyboard moves the cursor with arrow keys and shortcuts; the mouse moves the pointer, clicks, and drags. All three are directly involved in moving around and interacting with what is on the screen.

A scanner is an input device used to capture an image of a physical document or photograph and convert it into digital form. It plays no role in moving the pointer or the cursor around the screen, so it is not a navigation tool.

Exam takeaway: group devices by function before answering this style of question. Navigation devices control on-screen position (mouse, keyboard, cursor, trackball, joystick); scanners belong to the separate category of devices that digitise existing physical material.

Devices are classified by the direction in which data flows relative to the computer. An output device presents information that the computer has processed to the user, rather than sending new data into the computer.

A speaker takes processed audio signals from the computer and converts them into sound the user can hear, which makes it an output device. A keyboard and a mouse are input devices because they send commands and data into the computer. A microphone is also an input device, since it captures sound from the environment and converts it into data for the computer to process.

Exam takeaway: ask which way the information travels; if the device delivers processed results to the user (sound, image, print), it is output, and if it sends raw data or commands into the computer, it is input.

An Automated Teller Machine (ATM) is a self-service banking terminal designed to let customers carry out basic banking transactions without needing a bank teller present.

Its most common and defining use is allowing a customer to withdraw cash from their bank account using a bank card and a personal identification number. ATMs may also support related services such as balance enquiries or deposits, but cash withdrawal is the core, everyday function that gives the machine its purpose.

Record keeping and budget making are tasks typically handled by accounting or spreadsheet software, not by a cash machine, and watching movies has no connection to banking terminals at all.

Examination reminder: associate the ATM directly with cash-related banking transactions, especially withdrawing money, rather than with general record-keeping software functions.

Protecting sensitive data from being read by unauthorised people who should not have access means preventing them from making sense of the content even if they manage to view or copy the file. This is achieved by scrambling the data into an unreadable form that can only be reversed with the correct key.

This technique is encryption. It converts readable data (plaintext) into unreadable data (ciphertext), so that anyone viewing the file without the decryption key sees only meaningless characters. File permissions and file locks control who is allowed to open or edit a file, and passwords control access to a system or account, but none of these stop the content from being read if the underlying protection is bypassed. Encryption protects the data itself, which directly matches the idea of hiding content from prying eyes.

Exam takeaway: separate access control (permissions, locks, passwords, which decide who may open a file) from content protection (encryption, which hides what the file actually contains even if it is opened).

Microsoft PowerPoint is designed for creating slide shows made up of text, images, charts, and animations that are displayed to an audience, typically during a talk or lecture. Software built specifically for this purpose is classed as presentation software.

While PowerPoint is one of many productivity tools used in offices and could loosely be called part of general productivity software, that term is too broad and covers word processors and spreadsheets as well; the precise category that names PowerPoint's actual function is presentation software. It has no graphing or gaming purpose of its own.

Exam takeaway: when a question names a specific well-known program, choose the option that states its exact function rather than a broader category that could apply to several different programs.

A byte is the standard unit used to represent one character of data and is made up of 8 bits. Splitting a byte exactly in half gives a group of 4 bits.

This 4-bit group has its own specific name in computer studies, the nibble. A nibble is large enough to represent a single hexadecimal digit (0 to F), which is why it is a useful unit in low-level computing and digital electronics. Data is a general term for any facts processed by a computer, and bit refers to a single binary digit, not a group of 4, so neither term fits the specific half-byte grouping being asked about.

Exam takeaway: memorise the chain of data units: 1 bit is the smallest unit, 4 bits make a nibble, and 8 bits (2 nibbles) make a byte.

Some logic gates can act as a controllable switch, letting one input signal decide whether a second, changing signal passes through unchanged or gets flipped. Identifying which gate behaves this way means checking its output for both settings of the controlling input.

An XOR gate outputs 1 whenever its two inputs differ and outputs 0 whenever they are the same. If one input is held at 0 while the other input carries a changing digital waveform, the output simply follows that waveform unchanged, because a signal paired with 0 keeps its own value under exclusive-OR. If the control input is instead held at 1, the output becomes the exact opposite of the waveform at every instant, because a signal paired with 1 gets flipped under exclusive-OR. This makes the XOR gate a controllable inverter: unchanged at one control setting, inverted at the other.

The AND and OR gates cannot reproduce this behaviour, since holding one input fixed at either 0 or 1 forces their output to either always follow or always block the other signal, never to invert it. A NAND gate can invert a signal but does not offer this same unchanged-versus-inverted switching behaviour based on a control input in the way XOR does.

Exam takeaway: recognise the exclusive-OR gate as the standard controlled inverter, passing a waveform through untouched with one control level and flipped with the other.

The storage position of a file isn't one of its numerous characters because, it can be stored either in a primary or secondary memory.

Database models describe how records are structured and linked to one another. In a hierarchical database, each record has exactly one parent record, and a parent can have several child records, forming a tree-like structure similar to a family tree or an organisation chart, where movement between records follows the branches from parent to child.

A relational database instead stores data in independent tables linked by shared key values, without any strict parent-child tree structure. A network database is similar to the hierarchical model but allows a child record to have more than one parent, forming a web of connections rather than a single tree. An object-oriented database stores data as objects bundled together with the behaviour that acts on them, following the principles of object-oriented programming rather than a tree of parent-child records. Because the question specifically describes a tree-like structure built from single parent-child relationships, the hierarchical model is the correct match.

Examination reminder: "tree-like" and "parent-child" are the key phrases that identify the hierarchical database model in an examination question.

Writing a computer program almost always involves mistakes, whether small typing errors or deeper logical flaws that cause the program to behave incorrectly. The process of locating these errors, understanding why they occur, and correcting them so that the program runs as intended is called debugging.

The name comes from the term "bug," used to describe an error or defect in a program. Debugging typically involves running the program, observing where it fails or produces wrong results, tracing the fault back to the specific line or logic responsible, and then fixing that code.

This is different from compiling, which is the process of translating source code written in a programming language into machine-readable instructions, and from executing, which simply means running a program that has already been prepared. Scanning, in a computing context, usually refers to checking files for viruses or converting a physical document into digital form, neither of which involves fixing errors in program code.

Exam tip: remember that "debug" always relates to fixing errors, while "compile" relates to translating code and "execute" relates to running it; these are three distinct stages in developing and using a program.

An operating system (OS) is the core system software that manages a computer's hardware and resources, and provides the environment in which other programs can run. Its main duties include security, memory management, and process coordination on the local machine.

Stopping unauthorised users from accessing files that do not belong to them is a security function that the operating system genuinely handles, through user accounts, passwords, and file permissions. Allocating memory to running programs is also a core operating system function, since the OS must decide how much RAM each active program can use and prevent programs from interfering with each other's memory space.

Handling HTTP requests for web pages, however, is not something the operating system does. That task belongs to web server software (such as Apache or Nginx), which listens for requests from web browsers and sends back web page content over the internet. A computer can run an operating system perfectly well without ever hosting or responding to any HTTP request.

Exam tip: when a question lists OS duties alongside an internet-specific task like handling web requests, remember that anything tied specifically to serving websites belongs to web server or network application software, not the operating system itself.

RAM and ROM are both introduced early in computer studies as the two main categories of primary storage found inside a computer, even though they behave very differently from each other.

What RAM and ROM genuinely share is that they both deal with memory: both are physical chips inside the computer that store data the processor can read, RAM holding data and instructions currently in use, and losing them when power is removed, while ROM holds permanent instructions that survive a power cut. Their shared category is memory, even though their behaviour differs sharply.

Neither was invented by Bill Gates; RAM and ROM are hardware memory technologies developed by computer engineers, unconnected to Microsoft's founder, who built software rather than memory chips. The claim that they have "nothing in common" is incorrect, since they are both memory types used inside every modern computer. Their initials sharing the letter M for Memory is a coincidence of naming, not the meaningful similarity the question is testing.

When comparing two similar-sounding computer terms, look past superficial letter overlap and identify the actual functional category both items belong to, which here is memory.

Word processing packages include several built-in tools that assist writers with vocabulary, formatting, and document organisation, and each tool serves a distinct purpose.

The Thesaurus feature helps a user find synonyms and antonyms of words. When a writer selects a word and opens the Thesaurus, the software suggests alternative words with similar (synonym) or opposite (antonym) meanings, which helps avoid repeating the same word too often and improves the variety and precision of the writing.

The other options describe different, unrelated tools within word processing packages. Checking document statistics (such as word count, character count, or readability scores) is handled by a word count or readability tool, not the Thesaurus. Inserting citations is handled by a references or citation management tool. Creating a table of contents is handled by a dedicated table-of-contents generator that scans heading styles in the document, which again has nothing to do with finding alternative words.

Whenever a question links a word-processing feature specifically to synonyms or antonyms, that feature is the Thesaurus, since none of the other tools deal with word meaning at all.

In data processing, several terms describe what can happen to stored data, and each one has a precise technical meaning.

When new data is saved into a location that already holds older data, the new data replaces the old data completely at that same storage location. This action, where new information takes the place of existing information, is called overwrite. It happens, for example, when a file is saved again under the same name and the previous version is replaced by the updated content.

This is different from the other terms. File loss refers to data becoming inaccessible or lost, usually accidentally, not to a deliberate replacement. Delete means removing data so that nothing remains in that space. Re-write is not the standard technical term used in this context; the recognised term for replacing old data with new data in the same storage location is overwrite.

Whenever a question describes new data taking the place of old data at the same location, the keyword to associate with it is overwrite, not simply delete, since deletion leaves no replacement data behind.