Ch.4 Operating systems and computer architecture Flashcards Preview

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Flashcards in Ch.4 Operating systems and computer architecture Deck (10)
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1

What does a control bus do?

- Carries signals to synchronise the fetch-execute cycle
- Directs the CPU
- Can be unidirectional or bidirectional

2

What does a data bus do?

- Carries data that is being processed
- Bidirectional

3

What does an address bus do?

- Carries address locations of next item to be fetched
- Unidirectional

4

List the 5 different registers

1. MDR
2. MAR
3. PC
4. CIR
5. ACC

5

What is meant by the stored program concept?

- Programs / instructions are stored in memory
- Data is stored in memory
- Instructions are fetched and executed one after another

6

Describe the role of the Program Counter

- Holds the address …
- … of next / current instruction

7

What does a Program counter do?

- Increments to point to the address of the next instruction to be fetched

8

What does an accumulator (ACC)?

It holds the result of a calculation,
It is located in the Arithmetic Logic Unit (ALU)

9

What does a memory data register do (MDR)?

- Temporary storage between the central processing unit (CPU) and primary memory

10

Describe the role of the ALU

− Carries out calculations
− Carries out logical operations
− Holds temporary / interim values during calculations
− ...in a register called the accumulator (ACC)