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Computer System Overview Quiz
Computer System Overview
What does 'Computer Organisation' refer to?
The order in which programs are installed
The list of software available on a computer
How the hardware components of a computer are structured and connected to work together
The way files are arranged in folders on a disk
Computer Organisation refers to how the hardware components of a computer are structured and connected to perform tasks together.
Which set correctly lists the five core components of a computer system?
ALU, CU, Registers, Cache, ROM
Operating System, Drivers, Utilities, Libraries, Applications
Keyboard, Mouse, Monitor, Printer, Speaker
Input Unit, CPU, Output Unit, Memory Unit, Storage Unit
A computer system has five main units: Input Unit, CPU, Output Unit, Memory Unit (temporary) and Storage Unit (permanent), all connected by the System Bus.
Which component links ALL the units of a computer so they can communicate?
Control Unit
System Bus
Cache Memory
Register
The System Bus is a set of electrical pathways that connects the CPU, memory and input/output devices and allows them to communicate.
Apart from accepting data, what important job does the Input Unit perform?
It converts human-readable data into machine-readable binary form
It performs arithmetic on the data
It stores data permanently
It prints the processed result
The Input Unit converts human-understandable data such as keystrokes into binary (0s and 1s) that the CPU can process.
Which device converts physical documents or images into digital form?
Printer
Speaker
Scanner
Monitor
A scanner is an input device that converts physical documents/images into digital form.
Which of the following is an output device that produces a hard copy?
Scanner
Microphone
Mouse
Printer
A printer produces physical (hard copy) output on paper.
Which pair gives one input device and one output device, in that order?
Printer, Speaker
Mouse, Monitor
Monitor, Keyboard
Scanner, Microphone
A mouse is an input device and a monitor is an output device. Monitor-Keyboard is in the wrong order, and the other pairs are both output or both input.
What does the Output Unit do with processed binary data from the CPU?
Converts it back into human-readable form and presents it to the user
Stores it permanently on the hard disk
Sends it back to the input device
Encrypts it for security
The Output Unit converts processed binary data back into human-readable form and displays, plays or prints it.
The CPU is often called the 'brain' of the computer because it:
Connects all devices to the internet
Stores all files permanently
Fetches, decodes and executes instructions
Displays results on the screen
The CPU fetches, decodes and executes instructions — it does the actual processing.
What are the three main components of a CPU?
Input, Output and Storage
Data Bus, Address Bus and Control Bus
RAM, ROM and Cache
ALU, Control Unit and Registers
The CPU consists of the ALU (Arithmetic Logic Unit), the CU (Control Unit) and Registers.
Which part of the CPU checks whether A > B?
Cache
ALU
Program Counter
Control Unit
The ALU performs arithmetic (+, -, *, /) and logic operations such as comparisons (>, <, =).
Which CPU component directs and coordinates all activities, like a 'traffic police officer'?
Control Unit (CU)
Accumulator
Memory Data Register
Arithmetic Logic Unit (ALU)
The Control Unit directs and coordinates all the activities of the CPU and other components.
Registers are best described as:
Large, slow storage outside the CPU
Cables that connect the CPU to memory
Extremely small, extremely fast storage locations inside the CPU
Permanent storage for the BIOS
Registers are tiny, very fast storage locations inside the CPU that hold the data/instructions being processed right now.
Which register holds the address of the NEXT instruction to be executed?
Accumulator (AC)
Instruction Register (IR)
Memory Data Register (MDR)
Program Counter (PC)
The Program Counter (PC) holds the address of the next instruction to execute.
Which register holds the CURRENT instruction being executed?
Accumulator (AC)
Instruction Register (IR)
Memory Address Register (MAR)
Program Counter (PC)
The Instruction Register (IR) holds the instruction currently being executed.
Which register stores the result of ALU operations?
Accumulator (AC)
Instruction Register (IR)
Memory Address Register (MAR)
Program Counter (PC)
The Accumulator (AC) stores the result of ALU operations.
The Memory Address Register (MAR) holds:
The data being transferred to or from memory
The result of the last calculation
The address of the memory location to be accessed
The next instruction to run
MAR holds the address of memory to be accessed, while MDR holds the data being transferred.
Which register holds the data being transferred to or from memory?
IR
PC
MAR
MDR
The Memory Data Register (MDR) holds the data being transferred to/from memory.
What is the correct order of the CPU's instruction cycle?
Fetch → Execute → Decode
Fetch → Decode → Execute
Decode → Fetch → Execute
Execute → Fetch → Decode
The CPU first fetches an instruction from memory, then decodes it to understand it, then executes it — and the cycle repeats.
In the Fetch-Decode-Execute cycle, what happens in the DECODE step?
The CPU works out what the instruction means
The result is printed
The instruction is brought from memory
The instruction is deleted from memory
Decode means understanding what the fetched instruction means, before it is executed.
In the 'CPU as a chef' analogy, the small bowls on the counter holding ingredients needed right now represent:
The Control Unit
The hard disk
Registers
The ALU
Registers are like small bowls holding what is needed right now; the CU reads the recipe and the ALU does the cooking.
RAM is described as volatile. This means:
It is slower than a hard disk
It can only be read, never written
It stores the BIOS permanently
Its data is lost when the power is turned off
Volatile memory loses its contents when power is switched off; RAM is volatile.
What is the full form of ROM?
Random Only Memory
Read Only Memory
Rapid Output Memory
Register Operating Memory
ROM stands for Read Only Memory.
Which memory typically stores essential startup instructions such as the BIOS?
ROM
Cache
Register
RAM
ROM is non-volatile and stores essential startup instructions like the BIOS.
Which statement about RAM and ROM is correct?
Both lose data when power is off
RAM is non-volatile; ROM is volatile
RAM can be read and written; ROM is usually only read
ROM usually has a larger capacity than RAM
RAM can be read and written; ROM is usually only read. RAM is volatile, ROM is non-volatile, and RAM has the larger capacity (GBs vs MBs).
Which type of RAM is faster, more expensive and used in cache memory?
Flash
DRAM
ROM
SRAM
SRAM (Static RAM) is faster and more expensive, does not need constant refreshing, and is used in cache memory.
Which type of RAM needs to be refreshed constantly to retain its data?
L1 Cache
DRAM (Dynamic RAM)
SRAM (Static RAM)
ROM
DRAM is slower and cheaper, is used as main memory, and needs constant refreshing to retain data.
Where is cache memory located?
Between the CPU and main memory (RAM)
Inside the keyboard
Inside the hard disk
Between RAM and the hard disk
Cache is a small, very fast memory placed between the CPU and main memory.
Why is cache memory needed?
To connect input devices to the CPU
To store data permanently after power off
To bridge the speed gap between the fast CPU and slower RAM
To increase the size of the hard disk
The CPU is much faster than RAM; cache keeps frequently used data close to the CPU so it does not wait for RAM.
Which level of cache is built into the CPU chip and is the fastest but smallest?
L3 Cache
Main Memory
L2 Cache
L1 Cache
L1 cache is built into the CPU chip; it is the fastest and smallest level.
Which cache level is shared across CPU cores and is the largest among the caches?
L1
L3
Register
L2
L3 cache is shared across CPU cores, slower than L1/L2 but the largest cache.
Arrange these from fastest to slowest: RAM, Cache, Storage.
Cache, RAM, Storage
Storage, RAM, Cache
Cache, Storage, RAM
RAM, Cache, Storage
Cache is very fast and small, RAM is fast and larger, and storage is the slowest but largest.
The Storage Unit (secondary memory) is used for:
Coordinating CPU activities
Holding the next instruction address
Permanent storage that remains even when the computer is switched off
Temporary storage while programs run
Secondary memory provides permanent storage for data, programs and files even when power is off.
Which storage device is flash-based, faster and more expensive per GB than an HDD?
Optical disk
Magnetic tape
Hard Disk Drive
Solid State Drive (SSD)
An SSD is flash-based storage — faster, but more expensive per GB than a magnetic HDD.
A Hard Disk Drive (HDD) stores data using:
Static RAM cells
Magnetic storage
Registers
Laser-read pits
An HDD is magnetic storage with large capacity but slower speed.
Which of these is a small, portable, removable storage device used to move files between computers?
Pen drive (USB flash drive)
Cache
ROM chip
RAM
A pen drive is a small, portable, removable storage device.
Compared with secondary memory, primary memory (RAM) is:
Slower and cheaper per GB
Used only for backup
Faster but more expensive per GB
Non-volatile and permanent
Primary memory is very fast and expensive per GB; secondary memory is slower and cheaper.
Which statement about primary and secondary memory is correct?
Primary memory is permanent; secondary memory is temporary
They are interchangeable terms
Both are volatile
Primary memory is temporary; secondary memory is permanent
Primary memory (RAM) is volatile working memory; secondary memory (HDD/SSD) is non-volatile permanent storage.
Which bus carries the actual data being transferred and is bidirectional?
Address Bus
Data Bus
System Clock
Control Bus
The Data Bus carries the actual data and is bidirectional — data flows both ways.
Which bus carries the memory location where data should go or come from?
Address Bus
Data Bus
Power Bus
Control Bus
The Address Bus carries the memory address; it is unidirectional, flowing from the CPU outward.
Read/write commands that coordinate operations are carried by the:
Address Bus
Cache
Control Bus
Data Bus
The Control Bus carries control signals such as read/write commands and manages timing and coordination.
In the highway analogy of the system bus, the 'road sign telling the truck which city to go to' is the:
Control Bus
Data Bus
Register
Address Bus
The Address Bus is like the road sign (which location); the Data Bus is the truck (the data); the Control Bus is the traffic light (when to move).
What does SoC stand for in mobile systems?
Software on Computer
System on Chip
Storage on Card
Speed of CPU
SoC means System on Chip — CPU, GPU, memory controller and more combined on a single chip.
Why do mobile devices use an SoC instead of separate chips?
To save space and reduce power consumption
To make repairs easier
Because mobiles have no CPU
To increase the number of cables
Combining components on one chip saves physical space, reduces power use and improves performance — ideal for small, battery-powered devices.
In a smartphone, which component acts as both input and output?
Flash storage
Battery
Touchscreen
GPS sensor
A touchscreen combines input (tapping) and output (showing the response) in one interface.
Which is a key design priority for mobile systems compared with traditional computers?
Replaceable hard disks
Separate keyboard and monitor
Constant mains power supply
Power efficiency and battery life
Mobile devices run on batteries, so power efficiency is a critical design priority.
What is software?
A storage device
A set of instructions (programs) that tell the hardware what to do
A type of cable
The physical parts of a computer
Software is a set of instructions (programs) that tell computer hardware what to do.
Which of the following is system software?
A printer driver
A payroll program
MS Word
A photo editor
Device drivers, operating systems and utility software are system software. MS Word, payroll software and photo editors are application software.
What is the role of a device driver?
It stores the BIOS
It speeds up the CPU clock
It lets the operating system communicate with a specific hardware device
It edits documents
Device drivers allow the OS to communicate with specific hardware such as printers and graphics cards.
Antivirus and disk defragmenter programs belong to which category?
Device drivers
Specific purpose application software
Software libraries
Utility software (system software)
Antivirus, disk cleanup/defragmenter and file compression tools are utility software, a type of system software that performs maintenance and support tasks.
A railway reservation system is an example of:
System software
Specific purpose application software
General purpose application software
A device driver
Specific purpose software is designed for one specialised task, such as payroll or railway reservation.
Which statement about application software is correct?
It depends on system software (such as the OS) to run
It can run without any system software
It always runs in the background
It manages hardware directly
Application software always depends on system software like the operating system to function.
What is a software library?
A place where software CDs are stored
A type of operating system
A collection of pre-written, reusable code that programmers can use in their programs
A list of installed applications
A software library is a collection of pre-written, reusable code (functions, classes) used instead of writing that code from scratch.
Which Python library is used mainly for data visualisation/plotting?
NumPy
Math
Pandas
Matplotlib
Matplotlib is used for data visualisation; NumPy for numerical computation and Pandas for data handling and analysis.
Which is NOT an advantage of using software libraries?
Their code has already been tested by many developers
They make the program run without an operating system
They save time
They can be reused across many projects
Libraries save time, are tested and reliable, and are reusable. They do not remove the need for an operating system.
A student says, 'Cache and RAM are the same memory.' What is the correct understanding?
Cache is much smaller and faster and sits between the CPU and RAM
Cache is slower than RAM
Correct — both are main memory
Cache is a type of secondary storage
Cache is much smaller and faster than RAM and sits between the CPU and RAM to bridge the speed gap.