Systems Architecture

What is the purpose of the CPU?

Describe the fetch-decode-execute cycle in detail.

During the "fetch" stage of the FDE cycle, what happens?

Explain what happens during the "decode" stage of the FDE cycle.

During the "execute" stage of the FDE cycle, which CPU component typically performs arithmetic or comparison operations?

Explain why the fetch-decode-execute cycle repeats continuously while a computer is running.

A program contains the instruction "ADD the value in memory address 200 to the accumulator". Which stage of the FDE cycle actually performs the addition?

Explain the overall purpose of the CPU within a computer system, referring to the FDE cycle.

What is placed on the address bus at the start of the fetch stage?

Put the following stages of the FDE cycle in the correct order: Decode, Fetch, Execute.

What does the Program Counter (PC) do?

What is the purpose of the MAR and MDR?

What is stored in the Current Instruction Register (CIR)?

What is the role of the Accumulator (ACC) register?

A CPU is about to fetch an instruction. Which register holds the address of the memory location where that instruction is stored?

Describe what happens to the value in the PC immediately after an instruction has been fetched.

Which register is connected directly to the data bus and is used to transfer data being read from or written to memory?

Explain why a CPU needs registers at all, rather than just using RAM for everything.

During the decode stage, which register does the Control Unit examine to work out what operation to perform?

Match each register to its purpose: PC, ACC, MAR. Purposes: (a) holds address of next instruction, (b) holds address being accessed in memory, (c) stores results of calculations.

How does increasing clock speed affect computer performance?

What does having multiple cores in a CPU allow?

What is clock speed measured in?

Explain why a quad-core CPU does not always perform exactly four times faster than a single-core CPU running at the same clock speed.

How does increasing the size of a CPU's cache generally affect its performance?

A computer's clock speed is increased from 2 GHz to 4 GHz. Explain the effect this has on performance and identify one drawback.

Which of the following would generally give the BEST performance improvement for a task that can run entirely on one core and fits within a small amount of frequently-reused data?

Give two factors, other than clock speed, that affect the overall performance of a CPU.

Why might a laptop CPU be designed with a lower clock speed than a desktop CPU?

Explain how cache size, clock speed and number of cores together determine the overall performance of a CPU.

What is cache memory and why is it useful?

Where is cache memory typically located?

Explain why cache memory speeds up processing compared to fetching data directly from RAM every time.

What term describes the situation where the CPU finds the data it needs already in the cache?

If a CPU repeatedly needs data that is NOT in the cache, what is this called, and what must happen as a result?

Compared to RAM, cache memory is generally:

Explain why CPUs often have multiple levels of cache (e.g. L1, L2, L3).

A programmer notices that a program runs much slower the first time it processes a large dataset than on subsequent runs. Which of the following best explains this?

What is the von Neumann architecture?

In the von Neumann architecture, where are both the program instructions and the data stored?

What is meant by the "von Neumann bottleneck"?

Which of the following is a key principle of the stored-program concept underlying von Neumann architecture?

Name the main components involved in the von Neumann architecture and briefly state the role of each.

Why is the von Neumann architecture sometimes contrasted with the Harvard architecture (which uses separate memories for instructions and data)?

Explain how the fetch-decode-execute cycle relates to the von Neumann architecture.

Almost all modern general-purpose computers are based on which architecture?

Describe what is meant by "stored-program" in the context of computer architecture.

What is an embedded system? Give one example.

Which of the following is an example of an embedded system?

Explain the key difference between an embedded system and a general-purpose computer.

Which of these devices is LEAST likely to contain an embedded system?

Give three examples of everyday devices that contain embedded systems.

A car's anti-lock braking system (ABS) uses a dedicated microprocessor to control braking. What type of system is this an example of?

Explain why embedded systems are often designed to be low-power and low-cost compared to general-purpose computers.

A smart fridge has a small computer built in that monitors temperature and can connect to an app to alert the owner. Is this an example of an embedded system?

Suggest one advantage of using an embedded system rather than a general-purpose computer to control a device such as a microwave.

A CPU has a cache hit rate of 95%. Explain what this means and why a higher hit rate is desirable.

Which of the following best explains why increasing cache size has diminishing returns on performance beyond a certain point?

Which statement about the von Neumann architecture is correct?

A digital thermostat contains a small dedicated processor that only reads temperature sensors and controls a heating relay. Explain why this is described as an embedded system rather than a general-purpose computer.