Computer Hardware: CPU & fetch execute cycle.

Identify and explain the purpose of the two parts of the a.l.u

1. The arithmetic part which, deals with calculations. 2. The logic part which deals with any logical comparisons, such as the comparison of two numbers.

What are the four main jobs of the control unit?

1. To decide which instruction to carry out next and fetch it from memory. 2. To decode the instruction (work out what needs to be done to carry the instruction out). 3. To execute or follow the instruction. 4. Controls and monitors the hardware.

Describe how Clock speed influences the performance of a computers processor

A 3 GHz CPU performance 3 billion cycles a second.

What is a processor core?

A core can be defined as a single processor own control unit, ALU and registers. More advanced CPUs contain more than one core which will increase their ability to run many programs at the same time.

Identify and explain the role of the special-purpose register in the a.l.u

A dedicated register which is part of the ALU. When calculations take place on data, the results are initially stored in the accumulator before being transferred and stored in the main memory. Therefore, it is the default location to store any calculations before and by the ALU.

What is the difference between a dual core and a quad core?

A dual core CPU has two processors. A Quad core processor will have four processors.

Define and explain the purpose of a PC

A program counter is a CPU register that stores the address of the next instruction to be fetched. As many programme instructions are ordered in sequence, The program counter is automatically incremented by one every time instruction is fetched. Therefore the program counter paints to the next instruction address in every sequence.

Define and explain the purpose of the M a R memory address register

All program instructions are stored in the main memory of the CPU in a number of memory locations. Each memory location contains a unique address. The address of the current instruction or data being executed is temporarily stored in the MAR.

What is an instruction?

And instruction is an action that a program wants the CPU to carry out. For example, this could be to move specific data from one memory location to another. It instruction is made up of an operator and to operands. The CPU first fetches and instruction from the RAM. It's then decode this instruction to work out what operation I need to do and what the operands are. Finally, the CPU will execute the instruction.

Why is it quicker to search cache memory rather than ram?

Cache memory has a significantly lower storage capacity than RAM, resulting in reduced search times. Therefore using cache memory results in an increase in processor speed.

What is cache memory?

Cash memory is a type of very fast memory situated on or very close to the CPU. It is used to temperature and a cold instructions and data the CPU is likely to reuse. It is small capacity memory which is situated between the processor and RAM.

What is clock speed?

Clock speed indicates how fast the CPU can run.

What does it represent?

How many cycles the CPU can process in one second.

What is the advantage of having many core processors?

Increases your ability to run many programs at the same time.

What is the standard unit of measurement for clock speed?

Is measured in gigahertz.

What is the control unit?

Manages the execution of instructions which are usually in some sort of order using the fetch execute cycle. This is done by sending control signals to other parts of the CPU. It has three main jobs.

What is the arithmetic and logic unit?

Processes data that requires arithmetic calculation to be carried out, such as addition, multiplication, subtraction or division. It also performs logical comparisons to assist with decision-making by using logical operators AND, OR and NOT.

What is the purpose of a register?

Register is a high-speed temporary storage memory location. Each register has a specific purpose.

What is the IMMEDIATE ACCESS STORE internal memory?

Stories or programs and data temporarily whilst they are in use. During the fetch execute cycle, instructions are faxed from their specific Storage location and then IAS using an address. H memory location have a unique address assigned to it

Define and explain the purpose of the accumulator

The accumulator is a dedicated register which is part of the ALU. When calculations take place on data, The results are initially stored in the main memory. Therefore it is the default location to store any calculations performed for the ALU.

What is the main purpose of the CPU?

The brain of the computer. It's a microprocessor. To process programs and data. It does this by repeatedly fetching an instruction from memory and executing it. This is known as fetch execute cycle.

What is the advantage of using cache memory?

The control unit of the CPU will automatically check the cache memory first when fetching an instruction

Explain why increasing the clock speed does not automatically increase the performance of the processor.

The default setting on the computers clock is usually set to the maximum clock speed. Although clock speed is one way to measure computer power, increasing the clock speed does not automatically increase the performance of the processor.

Define fetch execute cycle

The fetch execute cycle is the steps a CPU goes through in order to process an instruction. At the start of the fetch execute cycle, both the data and instruction are loaded into the computers main memory so they're ready to be processed.

Define and explain the purpose of the IR the current instruction register

This register temporarily stored the current instruction to be decoded and then executed, having been fetched from the main memory.

Define and explain The purpose of the MDR memory data register

This register will temporarily store data being fetched from or written to the main memory of the CPU. Audacity transferred from main memory of the CPU goes via the MDR.