2. AQA GCSE (8525) SLR1 – 3.4 Von Neumann architecture

What architecture is the modern PC based on?

• Von Neumann architecture

• Harvard architecture

• Quantum architecture

• FPGA architecture

Answer explanation

The modern PC is based on Von Neumann architecture, which is characterized by having a single shared memory for data and instructions, allowing for sequential execution of instructions.

Who described the first design for modern computers with stored programs?

• John von Neumann

• Alan Turing

• Charles Babbage

• Ada Lovelace

Answer explanation

John von Neumann described the first design for modern computers with stored programs.

What is NOT a key characteristic of the von Neumann architecture?

• Internal clock

• Multiple control units

• Central Processing Unit

• Arithmetic Logic Unit

Answer explanation

The key characteristic NOT present in von Neumann architecture is Multiple control units. Von Neumann architecture has a single control unit.

What does the Program Counter do?

• Holds any data fetched from memory

• Holds the address of the next instruction to be executed

• Holds the address of where data is to be fetched from or stored into

• Holds the result of calculations

Answer explanation

The Program Counter holds the address of the next instruction to be executed, allowing the CPU to know where to fetch the next instruction from memory.

What is stored in the Memory Address Register?

• Any data which has been fetched from memory

• The next instruction to be executed

• The address of where data is to be fetched from or stored into

• The result of calculations

Answer explanation

The Memory Address Register stores the address of where data is to be fetched from or stored into, not the actual data or instructions.

What does the Arithmetic Logic Unit (ALU) do?

• Performs arithmetic and logical operations

• Decodes instructions

• Fetches instructions from memory

• Stores the address of the next instruction

Answer explanation

The Arithmetic Logic Unit (ALU) performs arithmetic and logical operations, making it the correct choice among the given options.

What is the purpose of the internal clock in the von Neumann architecture?

• To provide a pulse at a constant rate to synchronize components

• To keep track of time

• To store data temporarily

• To increase processing speed

Answer explanation

The purpose of the internal clock in the von Neumann architecture is to provide a pulse at a constant rate to synchronize components.

What is the function of the Memory Data Register?

• To hold the address of the next instruction

• To synchronize the CPU components

• To perform calculations

• To hold any data fetched from memory or about to be written to memory

Answer explanation

The Memory Data Register holds any data fetched from memory or about to be written to memory, making it the correct function of the register.

What happens during the fetch stage of the fetch-execute cycle?

• The instruction's address is incremented

• The next instruction's address is fetched from memory

• The instruction is decoded

• The instruction is executed

Answer explanation

During the fetch stage of the fetch-execute cycle, the next instruction's address is fetched from memory.

During the decode stage, where is the instruction copied?

• Into the ALU

• Into the accumulator

• Back into main memory

• Into the cache

Answer explanation

During the decode stage, the instruction is copied into the cache, not into the ALU, accumulator, or back into main memory.