Chapter 4: Computer Organization and Architecture (Set-1)
In a basic computer system, which unit converts user actions into machine-readable data for processing
A Output unit
B Memory unit
C Control unit
D Input unit
Input unit accepts data/instructions from the user and converts them into binary signals. These signals are then sent to memory or CPU for processing, enabling the computer to understand user input.
Which functional unit is mainly responsible for presenting processed results to the user
A Output unit
B ALU
C Cache memory
D Register
The output unit converts internal binary results into human-readable form, such as text, images, or sound. Common output devices include monitors, printers, and speakers that display final processed information.
Which part of a computer system stores instructions and data temporarily while programs run
A ROM
B Hard disk
C RAM
D Optical disk
RAM holds currently running program instructions and data for fast access by the CPU. It is volatile, meaning its contents are lost when power is turned off, unlike secondary storage.
Which unit performs arithmetic and logical operations inside the CPU
A Control unit
B ALU
C Output unit
D Input unit
The Arithmetic Logic Unit (ALU) handles operations like addition, subtraction, comparisons, AND/OR logic, and shifts. It works on data provided by registers and sends results back to registers or memory.
Which CPU component directs the execution of instructions and coordinates all operations
A Control unit
B Cache
C ALU
D RAM
The Control Unit (CU) fetches instructions, decodes them, and issues control signals to ALU, registers, memory, and I/O. It ensures operations happen in the correct sequence and timing.
Which functional unit is commonly called the “brain” of the computer system
A Output unit
B Keyboard
C CPU
D Secondary storage
The CPU executes instructions, controls system operations, and processes data using ALU, CU, and registers. It communicates with memory and I/O devices, making it the central processing component.
Which unit stores data and instructions for immediate access by the CPU
A Memory unit
B Output unit
C Input unit
D Speaker
The memory unit holds programs and data so the CPU can fetch instructions and operands quickly. It includes primary memory like RAM/ROM and interacts continuously with the CPU during execution.
Which storage is best suited for long-term data saving even after power is off
A Registers
B Cache
C Secondary storage
D RAM
Secondary storage like HDDs, SSDs, and flash drives is non-volatile and retains data permanently. It is slower than RAM but provides large capacity for files, software, and backups.
Which internal pathway carries data between CPU, memory, and I/O devices
A Power cable
B Printer cable
C Cooling fan
D System bus
A system bus is a set of electrical paths that transfers data, addresses, and control signals among CPU, memory, and I/O. It enables communication and coordination between major system components.
Which bus typically carries the location of data in memory
A Address bus
B Data bus
C Control bus
D USB bus
The address bus carries memory addresses from the CPU to memory or I/O devices. It tells where data should be read from or written to, and its width affects addressable memory size.
Which bus carries actual data values being transferred
A Control bus
B Data bus
C Address bus
D HDMI
The data bus transports actual data and instruction bits between CPU, memory, and I/O. A wider data bus can move more bits per transfer, improving data throughput in many operations.
Which bus carries signals like read/write and interrupt requests
A Control bus
B Data bus
C Address bus
D Network bus
The control bus carries control signals such as memory read, memory write, I/O read, I/O write, and interrupt signals. These signals coordinate timing and ensure correct operations across components.
What is the main role of an I/O interface in computer organization
A Print documents
B Convert programs
C Increase screen size
D Connect CPU to devices
An I/O interface bridges the CPU/system bus with external devices. It manages data transfer, device control signals, buffering, and sometimes speed matching, helping the CPU communicate reliably with peripherals.
Which unit houses motherboard, CPU, memory, and expansion cards together
A Scanner
B Monitor
C System unit
D Microphone
The system unit is the main computer case containing core hardware like the motherboard, CPU, RAM, storage drives, and power supply. It provides structure, protection, and internal connections.
Which CPU storage is the smallest but fastest for immediate operations
A Registers
B Hard disk
C RAM
D DVD
Registers are tiny storage locations inside the CPU used to hold operands, addresses, and intermediate results. They provide the fastest access, enabling quick instruction execution compared to cache or RAM.
Which register normally holds the address of the next instruction to execute
A MAR
B MDR
C Program Counter
D Accumulator
The Program Counter (PC) stores the memory address of the next instruction. After fetching an instruction, the PC usually increments or updates to a branch target, guiding sequential program execution.
Which register typically holds the currently fetched instruction for decoding
A Instruction Register
B Memory Address Register
C Program Counter
D Stack Pointer
The Instruction Register (IR) holds the instruction just fetched from memory. The control unit decodes it to determine required operations, operands, and control signals for the execution steps.
Which register holds the address of the memory location to read or write
A MDR
B MAR
C IR
D Accumulator
The Memory Address Register (MAR) stores the memory address for a read or write operation. It is used when the CPU accesses memory to fetch instructions or read/write data values.
Which register holds data being transferred to or from memory
A MAR
B PC
C CU
D MDR
The Memory Data Register (MDR) holds the actual data being read from memory or written to memory. It works with MAR during memory access operations, supporting reliable data transfer.
Which register commonly stores intermediate ALU results in many CPUs
A MAR
B PC
C Accumulator
D IR
The accumulator is a register used to store intermediate results from arithmetic and logic operations. Many instructions implicitly use it as an operand or destination, simplifying CPU design and execution.
Clock speed in a CPU mainly indicates what
A Cycles per second
B Storage size
C Screen resolution
D Disk capacity
Clock speed measures how many clock cycles occur each second, usually in GHz. It influences how quickly the CPU can perform basic steps, but overall performance also depends on architecture and efficiency.
Word length of a CPU generally means
A Monitor size
B Keyboard keys count
C Bits processed at once
D Printer speed
Word length is the number of bits the CPU can process in one operation, such as 32-bit or 64-bit. It affects register size, address handling, and the range of values processed efficiently.
Which CPU component generates control signals for data movement and operations
A ALU
B Control unit
C RAM
D Hard disk
The control unit generates timing and control signals that coordinate actions like register loading, ALU operation selection, memory access, and I/O operations. It ensures each instruction executes correctly step by step.
Which is a correct basic description of the data path in a CPU
A Physical data routes
B Power supply line
C Keyboard connector
D Cooling channel
A data path is the collection of hardware elements and connections that move and process data, including registers, ALU, and internal buses. Control signals direct how data flows through this path.
Which item best represents “control signals” in CPU operation
A Screen pixels
B Paper output
C Audio volume
D Read/write commands
Control signals are electrical signals that command components to perform actions like read, write, load register, or select an ALU operation. They manage timing and coordination of the entire instruction cycle.
Which concept allows overlapping of instruction stages for better CPU throughput
A Defragmentation
B Formatting
C Pipelining
D Compression
Pipelining divides instruction execution into stages like fetch, decode, execute, and write-back. Multiple instructions are processed in different stages simultaneously, improving throughput though hazards may require handling.
An interrupt in simple terms is best described as
A Signal to CPU
B File deletion
C Screen refresh
D Disk partition
An interrupt is a signal that requests the CPU’s attention, often from hardware or software. The CPU temporarily stops current execution, handles the interrupt service routine, then resumes the interrupted task.
In memory hierarchy, which level is generally the fastest
A Hard disk
B Cache
C RAM
D Optical disk
Cache memory is faster than RAM and stores frequently used data and instructions close to the CPU. It reduces average memory access time by avoiding slower main memory accesses whenever possible.
Which hierarchy order is generally correct from fastest to slowest
A Disk → RAM → Cache
B RAM → Disk → Cache
C Cache → RAM → Disk
D Cache → Disk → RAM
Memory hierarchy places the fastest, smallest storage near the CPU: registers and cache first, then RAM, then secondary storage like SSD/HDD. This balances speed, cost, and capacity.
Which memory is volatile and used as main memory in most computers
A RAM
B ROM
C DVD
D Flash drive
RAM is volatile, meaning it loses content when power is off. It serves as main memory where active programs and data reside for quick CPU access during processing and execution.
Which memory type is typically non-volatile and stores firmware instructions
A RAM
B Cache
C Registers
D ROM
ROM holds firmware like boot instructions and is non-volatile, retaining data without power. Modern systems often use flash-based ROM so firmware can be updated while still staying persistent.
Cache memory is mainly used to reduce
A Average access time
B Screen brightness
C Keyboard delay
D File size
Cache keeps frequently accessed data near the CPU, reducing the average time required to access memory. Even if RAM is fast, cache is faster and improves overall CPU performance significantly.
Which term best describes the time delay before memory starts delivering data
A Bandwidth
B Capacity
C Latency
D Resolution
Latency is the delay between a request and the start of data transfer. Lower latency improves performance, especially for frequent small accesses, and is a key reason cache is placed close to the CPU.
Memory bandwidth refers to
A Monitor thickness
B Disk weight
C Keyboard size
D Data per second
Bandwidth is the amount of data that can be transferred per unit time, such as MB/s or GB/s. Higher bandwidth allows faster movement of large blocks of data between memory and CPU.
Which concept uses disk space to act like extra RAM
A ROM
B Virtual memory
C Cache line
D Register file
Virtual memory uses secondary storage to extend available main memory. When RAM is full, pages are swapped between disk and RAM, allowing larger programs to run, though slower than real RAM access.
Which memory is closest to the CPU and part of the CPU itself
A Registers
B Hard disk
C RAM
D SSD
Registers are located inside the CPU core and provide the fastest storage for operands and control information. They are essential for instruction execution and are accessed in a single or few CPU cycles.
Which is a correct example of secondary storage device
A Register
B Cache
C SSD
D ALU
An SSD is non-volatile secondary storage used for long-term data retention. It is faster than traditional HDDs but still slower than RAM, and it stores the operating system, applications, and files.
A memory address is best described as
A Storage location number
B File name
C Keyboard shortcut
D Screen position
A memory address uniquely identifies a storage location in memory. The CPU uses addresses to read or write data and instructions, enabling organized access to large memory spaces.
Which unit mainly decides whether an instruction should fetch data from memory or write data to memory
A Output unit
B Mouse
C Printer
D Control unit
The control unit decodes instructions and issues read/write control signals accordingly. It coordinates MAR/MDR usage and timing so that memory operations occur correctly during instruction execution.
Which functional unit includes RAM and ROM together in basic classification
A Memory unit
B Input unit
C Output unit
D ALU unit
In basic organization, the memory unit includes primary storage components like RAM and ROM. These store data and instructions needed for processing, with RAM used for active tasks and ROM for firmware.
Which component helps connect external devices like keyboard and printer to the system bus
A ALU
B Cache memory
C I/O interface
D Program Counter
The I/O interface manages communication between the system bus and peripheral devices. It handles device control, buffering, and sometimes protocol conversion so the CPU can interact efficiently with slow devices.
Which unit is responsible for converting processed binary results into printed output
A Input unit
B Output unit
C Memory unit
D Control unit
Output devices like printers receive processed data and convert it into a physical form. The output unit ensures the information generated inside the computer becomes usable for the user in the desired format.
Which CPU component is most directly responsible for instruction decoding
A Control unit
B ALU
C RAM
D Hard disk
Instruction decoding is handled by the control unit using the instruction register contents. It interprets opcode and addressing details, then generates the necessary control signals to execute that instruction correctly.
Which statement best describes a register in simple terms
A Long-term storage device
B Screen output unit
C External input device
D Tiny fast CPU storage
Registers are very small storage locations inside the CPU, used to hold data, addresses, and instructions temporarily. Their speed supports fast execution, making them much quicker than cache or RAM.
Which memory type usually stores the BIOS or firmware program
A RAM
B Cache
C ROM
D Register
Firmware like BIOS/UEFI is stored in non-volatile ROM so it remains available when the system starts. It initializes hardware and begins the boot process before the operating system loads.
Which feature mainly increases CPU performance by doing more work per clock cycle
A Efficient architecture
B Larger monitor
C Better keyboard
D More printer ink
CPU performance depends on more than clock speed. Efficient architecture improves instruction throughput using techniques like pipelining, caching, and better instruction handling, enabling more useful work per cycle.
Which unit performs comparisons such as greater-than or equal-to decisions
A Output unit
B ROM
C Power supply
D ALU
The ALU performs logical comparisons and sets flags based on results. These comparisons are essential for decision-making instructions like conditional branches, enabling programs to choose different execution paths.
Which term best matches the “levels” arrangement of memory from fastest to slowest
A Screen hierarchy
B File formatting
C Memory hierarchy
D Device casting
Memory hierarchy organizes storage by speed, cost, and size: registers, cache, RAM, and secondary storage. This structure improves performance by keeping frequently used data in faster, smaller memory near the CPU.
Which CPU register pair is most associated with memory read/write operations
A MAR and MDR
B PC and IR
C ALU and CU
D RAM and ROM
MAR holds the memory address to access, while MDR holds the data being transferred. Together they support correct memory read/write operations, allowing the CPU to communicate with memory efficiently and accurately.
Which unit ensures different parts of the computer work in the correct timing order
A Output unit
B Control unit
C Secondary storage
D Speaker
The control unit coordinates the fetch-decode-execute cycle using timing and control signals. It synchronizes actions of ALU, registers, memory, and I/O so each instruction step occurs in proper order.