Chapter 1

Question 1

The Control Unit

Answer 1

Controls & coordinates the activities of the CPU and other parts of the computer. It controls the F-D-E cycle by sending signals through the control bus.

Question 2

The Clock

Answer 2

A vibrating quartz crystal the coordinates instruction executions.

Question 3

The Arithmetic & Logic Unit

Answer 3

Performs arithmetic and logic operations on the data such as: add, subtract, multiply and divide. It can also perform shift operations and the Boolean logic operations AND, OR, NOT & XOR.

Question 4

Register

Answer 4

A memory location within the processor that stores specific data and operate at a very high speed.

Question 5

Cache

Answer 5

A small amount of memory in the CPU that can be accessed even faster than RAM.

Question 6

The Control Bus

Answer 6

A bi-directional bus: signals are sent both to and from the processor. Data and Address buses connect all computer components together and control lines are needed to ensure all components use the Data and Address busses fairly.

Question 7

Control Lines include:

Answer 7

• Bus Request: A device is requesting use of a Data bus
• Bus Grant: The CPU has granted access to a Data bus
• Memory Write: Let the data on the Data bus write to a memory location
• Memory Read: Let data from address location be put on the Data bus
• Interrupt Request: A component is requesting access to the CPU
• Clock: Synchronises the F-D-E cycle

Question 8

The Data Bus

Answer 8

Provides a bi-directional path for moving data and instructions between components.

Question 9

The Address Bus

Answer 9

Uni-directional bus, that transmits the location of stored information. Allows the CPU to send the address to RAM.

Question 10

No. of typical general purpose registers

Answer 10

16

Question 11

Accumulator (Acc)

Answer 11

Used by the ALU to perform arithmetic, logic and shift operations.

Question 12

Program Counter (PC)

Answer 12

Keeps track of thee address of the next program instruction. Sends the address to the memory address register.

Question 13

Memory Address Register (MAR)

Answer 13

Receives the address of the next instruction from the program counter and sends it to the memory.

Question 14

Memory Data Register (MDR)

Answer 14

Receives the instruction from the memory. Copies the instruction to the current instruction register.

Question 15

Current Instruction Register (CIR)

Answer 15

Receives the instruction form the memory data register before it is decoded by the control unit.

Question 16

Fetch (FDE Cycle)

Answer 16

1. The address of the next instruction from the program counter to the memory address register
2. The instruction held at that address is copied to the memory data register. Simultaneously, the content of the PC is incremented so that it holds that address of the next instruction.
3. The contents of the MDR are copied to the current instruction register (CIR)

Question 17

Decode (FDE Cycle)

Answer 17

4. The instruction held in the CIR is decoded. The instruction is split into opcode and operand and the opcode is used to determine the type of instruction and what hardware to use to execute it. The operand holds either:

• the address of the data to be used with operation, which is then copied to the MAR
• the actual data to be operated on, which will be copied to the MDR
  -the data to be operated on may be passed to the ALU/Acc

Question 18

Execute (FDE Cycle)

Answer 18

5. The appropriate instruction/opcode is carried out on the operand.

Question 19

Instruction word

Answer 19

Contains an opcode and an operand

Question 20

Factors of processor performance

Answer 20

• Clock Speed
• Number of cores
• Amount of RAM
• Amount and type of Cache
• Size of words computer is designed to use
  -Pipelining
  -Amount & size of general purpose registers

Question 21

Overclocking

Answer 21

When you make the clock run faster than its
design parameters; this causes more FDE cycles to occur per
second, but the increased electrical signals cause more heat,
increasing the risk of damage. Precautions such as additional
heat sinks and fans to dissipate
the heat are required.