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12 Cards in this Set
- Front
- Back
Name the 3 main internal components of a computer system. |
(ALU, CU and Registers), Memory and input/ output devices. |
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What is the Central Processing Unit? |
This is the heart of the computer, responsible for executing programs and supervising the functioning of other parts of the system. |
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What is the Control Unit? |
This is a digital control unit that co-ordinates the movement of data, sequencing of instructions and directs operations of other components by providing control and timing signals (eg. an internal clock) |
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What is the Arithmetic Logic Unit? |
This carries out operations on data associated with instructions being executed. (eg. Boolean and Logical.) |
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Name the 3 types of internal memory. |
Main memory- RAM and ROM, Cache Memory. |
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Name the functions of these types of memory. |
RAM- Stores the operating system being used and data items. ROM- Stores a boot program that runs when the computer is first turned on. Cache Memory- Stores copies of the most frequently used memory locations. |
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The stages on the fetch Execute Cycle |
Instruction FETCHED from memory to control unit Instruction DECODED determine action carried out Instruction EXECUTED |
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What is registers? |
A high speed memory location on the CPU, faster than internal memory. |
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Name the 4 registers included in the cycle and what they do. |
Program Counter(PC) Stores address location in memory (Gets incremented) Memory Address Register(MAR) Stores the address of a memory location Memory Data Register (MDR) Stores data that has just been fetched. Current Instruction Register (CIR) Stores the instruction currently being executed. |
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Name the 3 buses used for communication systems and what they do. |
Address Bus - Identifies a physical location in memory. Data bus - Allows the transfer of data between 1 component to another. Control Bus - Carries commands from the the CPU to other devices. |
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Stages of the Fetch Phase |
Address to be executed and loaded into PC - PC contents placed in MAR (using Address Bus to get location) - PC increments for the location of the next instruction to be executed. - read signal sent to control bus to memory, instruction from MAR to the MDR via data bus - instruction held at this address and copied to the MDR - Instruction copied to current instruction register examined or decoded by the processor. |
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Stages of Decode Phase |
Instruction held in CIR sent to the control unit to be decoded by the processor, using an instruction set which control unit is aware. |