1.1.1 FDE, CPU, Von Neumann.

Question 1

What is the Central Processing Unit(CPU) ? (2 points)

Answer 1

The “brain” of the computer.
Processes Instructions.

Question 2

What is Opcode ? (Operation Code)

Answer 2

An instruction for the CPU to process.

Question 3

What is Operand ?

Answer 3

Data for the CPU to run an instruction on.

Question 4

What is the stored program concept ?

Answer 4

Instructions and data are stored in memory together.

(The Von Neumann Architecture)

Question 5

What happens in the Fetch part of the FDE Cycle ?

Answer 5

The CPU finds the requested Address and Retrieves data.

Question 6

What happens in the Decode part of the FDE Cycle ?

Answer 6

The data is read as Opcode and Operand(s).

Question 7

What happens in the Execute part of the FDE Cycle ?

Answer 7

The computer follows the instruction to act on the data, or fetch more.

Question 8

What are the steps of the FDE Cycle ? (5 steps)

Answer 8

1. Copy the address held in PC to MAR
2. Add 1 to PC and load the value at the address in the MAR to the MDR
3. The instruction in the MDR is copied in the CIR.
4. In the CIR instruction is decoded
5. Execute

Question 9

What is an Input Device ? ( 3 examples)

Answer 9

Any hardware giving information to the computer.

E.g. Microphone, Keyboard, Mouse.

Question 10

What is an Output Device ? (3 examples)

Answer 10

Any hardware giving information to the user.

E.g. Monitor, Speaker, Light.

Question 11

What does the Control Unit (CU) do ? (2 points)

Answer 11

Decodes Instructions.

Sends control signals to co-ordinate the movement of data through the CPU.

Question 12

What does the Arithmetic Logic Unit (ALU) do ?

Answer 12

Performs maths and logic functions.

Question 13

What is Binary ?

Answer 13

A base 2 number system where each digit can be 0 or 1.

Question 14

What is a register ?

Answer 14

High speed memory built within the CPU.

Question 15

What does the Program Counter(PC) do ?

Answer 15

Points to the next instruction.

Question 16

What does the Memory Address Register(MAR) do ?

Answer 16

Stores the address from which data or an instruction is to be read/written.

Question 17

What does the Memory Data Register(MDR) do ?

Answer 17

Temporarily stores data read or written to memory.

Question 18

What does Current Instruction Register(CIR) do ?

Answer 18

Holds the current instruction, divided into Operand and Opcode.

Question 19

What does the Accumulator do ?

Answer 19

A memory register that stores data.