Term
| What is the purpose of a CPU? |
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Definition
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Term
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Definition
The processing of data.
The searching, sorting, calculating and decision making of the computer. |
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Term
| What is the Fetch - Decode - Execute cycle? |
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Definition
| The steps needed for processing to take place. |
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Term
| What happens at the first (FETCH) step of the Fetch-Execute Cycle? |
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Definition
| The CPU fetches data and instructions from main memory to store in its temporary memory areas (registers). |
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Term
| What is the 'address bus?' |
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Definition
| A hardware path that leads from the CPU to the main memory. |
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Term
| What is put on the adress bus by the CPU? |
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Definition
| The address of the next item to be fetched. |
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Term
| What hardware path does the data take from the main memory to the CPU? |
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Definition
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Term
| What happens in the second part of the Fetch-Execute cycle with the CPU's 'instruction set'? |
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Definition
| The CPU decodes the data using its instruction set and prepares the chip in readiness for the execute step. |
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Term
| What happens at the third part of the Fetch-Execute cycle? |
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Definition
| The instruction called for is carried out upon the data. |
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Term
| What happens with the result of data processed by the CPU? |
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Definition
| It is stored in another register. |
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Term
| What happens one the execute stage of the Fetch-Execute cycle is complete? |
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Definition
| The CPU sets up to begin the cycle again. |
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Term
| What are the three main parts of the CPU? |
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Definition
- Control Unit
- Immediate Access Store (IAS)
- Arithmetic and Logic Unit (ALU)
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Term
| What are the three jobs of the Control Unit? |
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Definition
- Controls and monitors the hardware attached to the system to make sure the commands given by the application software are used correctly.
- Controls the input and output of data so the signals go to the right place at the right time.
- Controls the flow of data within the CPU.
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Term
| What does the Immediate Access Store (IAS) do? |
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Definition
| It holds the data and programs needed by the Control Unit at that instant. |
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Term
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Definition
| Because the Backing Storage (ie the hard disk) is too slow to be able to run applications directly. |
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Term
| What is the Arithmetic Logic Unit (ALU?) |
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Definition
| The part of the CPU that processed data by minipulating it or acting upon it. |
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Term
| What are the two parts of the ALU? |
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Definition
| The Arithmetic part and the Logic part. |
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Term
| What does the Arithmetic part of the ALU do? |
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Definition
Performs calculations on the data.
ie 2+3=5
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Term
| What does the Logic part of the ALU do? |
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Definition
The logic and comparisons.
ie = < >
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Term
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Definition
| The amount of data a CPU can process in a certain time. |
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Term
| What is the clock speed controlled by? |
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Definition
| A quartz crystal inside the CPU. |
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Term
| What is the clock speed measured in? |
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Definition
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Term
| What is one cycle per second equal to? |
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Definition
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Term
| How many instructions are being carried out by a computer running at 1GHz? |
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Definition
| A thousand million per second. |
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Term
| What is the typical clock speed of a modern desktop? |
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Definition
| Three thousand million cycles per second (3 GHz). |
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Term
| What does the clock speed affect? |
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Definition
The performance of the CPU
Higher clock speed = higher performance |
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Term
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Definition
The clock is adjusted so it will run faster than originally intended.
This makes the CPU run hotter and so extra cooling fans are needed. |
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Term
| How many processes can a CPU perform at once? |
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Definition
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Term
| What do 'dual core' and 'quad core' mean? |
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Definition
The computer runs with two CPUs or four CPUs.
This makes it perform better (but not exactly twice as well)
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Term
| Where is most data stored? |
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Definition
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Term
| Why is data loaded into the RAM rather than being taken straight from the hard disk? |
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Definition
| Accessing data from the RAM is a lot faster than accessing it from the hard disk. |
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Term
| Why is data stored in the cache memory? |
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Definition
| To avoid delays in getting data to the CPU. |
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Term
| What kind of memory is looked into first for new data and instructions? |
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Definition
| The cache, then the RAM, then the hard disk. |
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Term
| Why is the cache called 'volatile memory?' |
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Definition
| Because when the computer is turned off, the data stored there is lost. |
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