IT Computer Architecture 1 — Questions and Answers
Question 1: What is the primary function of the Arithmetic Logic Unit (ALU) in a CPU?
- Store program instructions
- Perform arithmetic and logical operations (Correct answer)
- Control data flow between components
- Manage input/output operations
Correct answer: Perform arithmetic and logical operations
The ALU executes arithmetic operations (addition, subtraction) and logical operations (AND, OR, NOT) on binary data.
Question 2: Which type of memory loses its contents when power is removed?
- ROM
- Flash memory
- RAM (Correct answer)
- EEPROM
Correct answer: RAM
RAM (Random Access Memory) is volatile memory, meaning all stored data is lost when the power supply is interrupted.
Question 3: During the fetch-decode-execute cycle, what happens in the 'decode' phase?
- The CPU retrieves the instruction from memory
- The control unit interprets the instruction's opcode (Correct answer)
- The ALU performs the required operation
- The result is written back to a register
Correct answer: The control unit interprets the instruction's opcode
During decode, the control unit interprets the fetched instruction's opcode to determine which operation must be performed.
Question 4: What is the primary purpose of cache memory in a computer system?
- To provide permanent data storage
- To expand total addressable memory capacity
- To reduce the speed gap between the CPU and main memory (Correct answer)
- To store the operating system kernel
Correct answer: To reduce the speed gap between the CPU and main memory
Cache stores frequently accessed data close to the CPU, minimizing the wait time caused by the slower access speed of main memory.
Question 5: Which bus in a computer system carries the memory location being accessed by the CPU?
- Data bus
- Control bus
- Address bus (Correct answer)
- I/O bus
Correct answer: Address bus
The address bus transmits the memory address the CPU wants to read from or write to, specifying the exact location in memory.
Question 6: What distinguishes RISC (Reduced Instruction Set Computer) from CISC architecture?
- RISC uses complex multi-cycle instructions
- RISC uses simple instructions that each execute in one clock cycle (Correct answer)
- RISC supports more addressing modes than CISC
- RISC requires more memory for program storage than CISC
Correct answer: RISC uses simple instructions that each execute in one clock cycle
RISC uses a small set of simple, uniform instructions that each complete in one clock cycle, enabling faster throughput through hardware simplicity.
Question 7: What is CPU pipelining?
- Storing multiple programs in memory simultaneously
- Breaking instruction execution into concurrent stages so multiple instructions overlap (Correct answer)
- Connecting multiple CPUs to work on a single task
- Prefetching frequently used data near the processor
Correct answer: Breaking instruction execution into concurrent stages so multiple instructions overlap
Pipelining divides instruction execution into sequential stages (fetch, decode, execute, write-back) so different instructions occupy different stages simultaneously.
IT Computer Architecture 1
What is the primary function of the Arithmetic Logic Unit (ALU) in a CPU?