1.1 Hardware - CPU

Question 1

What does CPU stand for?

Answer 1

Central Processing Unit

Question 2

What numerical values are stored in the computer?

Answer 2

Ones and Zeros

Question 3

Where are the values stored in the CPU

Answer 3

In the Transistors

Question 4

What does the binary in transistors do?

Answer 4

One means it lets current pass through
Zero means it won’t pass current through

Question 5

What is the purpose of a CPU?

Answer 5

Process Data and instructions as well as control the rest of the computer system.

Question 6

Where does the CPU get its data from?

Answer 6

Input Device or memory

Question 7

Where is the Data stored while being processed

Answer 7

Primary Storage

Question 8

What process does a CPU go through.

Answer 8

Receives instructions or data form an input source or the memory, its then processed and sent to the output or secondary storage.

Question 9

Name some input devices

Answer 9

Keyboard
Mouse
Camera
Scanner
Microphone
Trackball
2D/3D Scanner
Touch Screen

Question 10

Name Output Devices

Answer 10

Monitor
Speaker
Printer

Question 11

What is meant by CPU architecture.

Answer 11

The design of the Microprocessor, a integrated circuit. Where the components of the CPU combine to make a single unit.

Question 12

What are the 6 main components of a CPU. What do they do? Advanced

Answer 12

Control Unit (CU) - This manages and executes the instructions. Makes sure that everything happens at the right time and in the correct order. Runs the fetch-decode-execute cycle.

Arithmetic Logic Unit (ALU) - This performs arithmetic and logic calculations. It can also compare data. The gateway between primary and secondary storage.

Registers - High Speed Memory that stores data to be processed. Stores result from the ALU and is faster than internal Memory. Stores small data needed for processing. There are many types of registers.

Internal/Cache Memory - Fast access temporary storage known as Random Access Memory (RAM). Stores Data from the Registers when data is not in use.

Buses - Wires which through the data travels around the motherboard or different parts of the computer. There are 3 types of buses.

Clock - Sends regular pulses to synchronise the computer’s hardware components. The frequency of the pulses is known as clock speed which is measured in Hertz(Hz)

Question 13

What are the 6 main components of a CPU. What do they do? Basic

Answer 13

Control Unit (CU) - Manages and executes the instructions.

Arithmetic Logic Unit (ALU) - Gateway between primary and secondary storage that does calculations.

Registers - High Speed Memory that stores ALU Data.

Internal/Cache Memory - Fast access temporary storage RAM.

Buses - Wires that data travels through.

Clock - Synchronises computer components.

Question 14

Describe the 3 types of Buses

Answer 14

Address Bus - When data is saved the address of the location needs to be sent. The storage address alway travels along with the address bus.

Data Bus - Data needs to be moved between several parts of a computer. The path the data takes is called a Data Bus.

Control Bus - Used by the controller to send control signals throughout the computer.

Question 15

Name the 5 different registers.

Answer 15

Program Counter (PC)
Current Instruction Register (CIR)
Accumulator (ACC)
Memory Address Register (MAR)
Memory Data Register (MDR)

Question 16

What design are most General Purpose Computers based on?

Answer 16

Von Neumann Architecture

Question 17

What is the Von Neumann Architecture?

Answer 17

Storing the program instructions in the same memory as the data.

Question 18

What are the key elements of Von Neumann Architecture?

Answer 18

Data & Instructions are stored as Binary digits and stored in the primary storage.

Instructions are fetched from memory in order

Processor decodes and executes instructions then fetch next instruction.

Cycle continues until no instructions left.

Question 19

Explain the 5 registers used in Von Neumann Architecture.

Answer 19

Program counter (PC) holds the memory address of the next instruction to be fetched from primary storage.

Memory address register (MAR) has the address of the current instruction that is to be fetched from the memory, or the address of where it will be transferred to.

Memory Data Register (MDR) holds the contents from address in the MAR or data that is going to be moved to primary storage.

Current Instruction Register (CIR) holds instructions which are currently being decoded and executed.

Accumulator (ACC) is used by the ALU to hold data being processed along with the results of calculations.

Question 20

What are the 7 steps of the fetch-decode-execute cycle.

Answer 20

1. Memory address held in the Program Counter is copied into the Memory Address Register.
2. Address in the PC is increased by 1. PC holds the address of the next instruction to be fetched.
3. Processor sends signal along with address bus to the memory address held in the Memory Data Register.
4. Instruction and Data held in that memory address is sent along the data bus to the Memory Data Register.
5. Instructions/Data held in MDR is copied to the Current Instruction Register.
6. Instruction/Data held in CIR is decoded then executed. Results are stored in the Accumulator.
7. Cycle returns to step One.

Question 21

What factors can affect the CPUs Performance?

Answer 21

Clock Speed
Cache Size
Nr of Cores

Question 22

What is the unit of measurement for Clock Speed?

Answer 22

Hertz (Hz)

Question 23

What does the Clock speed affect?

Answer 23

Speed that the computer can run the fetch-decode-execute cycle. Higher Clock Speed = More instruction done in set amount of time.

Question 24

What is Overclocking? State the effects of doing this.

Answer 24

Manually setting the clock speed to be faster.
This increases speed but uses more energy and creates more heat, If this heat isn’t transferred out then the CPU can overheat and shorten the lifespan.

Question 25

What is Underclocking?

Answer 25

Setting the speed lower than original design using less power and making less heat. This increases the Battery Life of the Device.

Question 26

What is Cache?

Answer 26

Fast access random access memory that is very expensive. Due to costs computer usually have very little of it (kB or MB).

Question 27

What does Cache do?

Answer 27

Temporarily stores data and instructions that the CPU is likely to use.

Question 28

How does the Cache amount affect the CPU?

Answer 28

Allows for fast processing as CPU doesn’t need to wait for it to come form the RAM.
More storage = Less time processor needs time to fetch instructions.

Question 29

What are CPU Cores?

Answer 29

The PU in a CPU is a Core

Question 30

What do Cores do?

Answer 30

Each core can run a fetch-decode-execute cycle on instructions.

Question 31

How do cores affect the Computer?

Answer 31

With more cores more instructions can be done at the same time.
More core = More Processing Power

Question 32

What can hold back the cores in a CPU?

Answer 32

If instruction 2 needs the result of instruction 1 then it will wait for Instruction 1 to finish processing.