Paper 1 Computer architecture Flashcards
What is the role of the CPU (central processing unit) in a computer?
The computer’s central processing unit (CPU) is the portion of a computer that retrieves and executes instructions.
What are the three operations that a central processing unit constantly repeats?
The cycle of fetching, decoding, and executing an instruction is continually repeated by the CPU whilst the computer is turned on
How does the Fetch-decode-execute cycle work?
The processor checks the program counter to see which instruction to run next.
The program counter gives an address value in the memory of where the next instruction is.
The processor fetches the instruction value from this memory location.
Once the instruction has been fetched, it needs to be decoded and executed. For example, this could involve taking one value, putting it into the ALU, then taking a different value from a register and adding the two together.
Once this is complete, the processor goes back to the program counter to find the next instruction.
This cycle is repeated until the program ends.
The engine management system of a car is for a fixed purpose and not designed to do anything else. Identify the name for this type of system.
Embedded system
The CPU often uses cache before checking main memory. What is the function of the level 1 cache?
Level 1 cache (L1 cache) is a memory cache that is directly built into the microprocessor, which is used for storing the microprocessor’s recently accessed information, thus it is also called the primary cache.
The CPU often uses cache before checking main memory. Describe the functioning of level 2 cache.
The level 2 cache serves as the bridge for the process and memory performance gap. Its main goal is to provide the necessary stored information to the processor without any interruptions or any delays or wait-states.
The CPU often uses cache before checking main memory. Describe the functioning of level 3 cache.
A memory bank built onto the motherboard or within the CPU module. The L3 cache feeds the L2 cache, and its memory is typically slower than the L2 memory, but faster than main memory. The L3 cache feeds the L2 cache, which feeds the L1 cache, which feeds the processor.
How does the data bus that links the components of the CPU work?
The data bus carries the data between the processor and other components. The data bus is bidirectional (data can flow both directions)
How does the address bus that links the components of the CPU work?
The address bus carries memory addresses from the processor to other components such as primary storage and input/output devices. The address bus is unidirectional (data can flow in only one direction).
How does the control bus that links the components of the CPU work?
The control bus carries control signals from the processor to other components. The control bus also carries the clock’s pulses. The control bus is unidirectional (data can flow in only one direction).
