Chapter 3

Question 1

What does the Control Unit do?

Answer 1

Manages other components of the CPU

Question 2

What does the Arithmetic Logic Unit do?

Answer 2

Carries out mathematical calculations

Question 3

What are registers?

Answer 3

Small areas of storage in the CPU

Question 4

What are the 5 registers in the CPU?

Answer 4

PC, MAR, MDR, CIR, ACC

Question 5

What does the Program Counter do?

Answer 5

Holds the ADRESS of the NEXT instruction

Question 6

What does the Memory Address Register do?

Answer 6

Contains address of RAM to be written to / read from

Question 7

What does the Memory Data Register do?

Answer 7

Contains the data to be written to RAM / read from RAM

Question 8

What does the Current Instruction Register do?

Answer 8

Holds the instruction currently being decoded or executed

Question 9

What does the Accumulator do?

Answer 9

Holds data stored by ALU during operations

Question 10

What does the Control bus do?

Answer 10

Carries control signals, CU -> CPU
Control signals = [‘read’ or ‘write’]
Carries Control signals, CPU -> RAM

Question 11

What does the Address Bus do?

Answer 11

Carries addresses ONE WAY
MAR -> RAM

Question 12

What does the Data Bus do?

Answer 12

Carries data to be written from MAR -> RAM.
When data is read, it carries read data from RAM -> MAR

Question 13

What is meant by “fetch” in the fetch-decode-execute cycle?

Answer 13

An instruction is taken from RAM -> CPU

Question 14

What is meant by “decode” in the fetch-decode-execute cycle?

Answer 14

Instruction is decoded by CU

Question 15

What is meant by “execute” in the fetch-decode-execute cycle?

Answer 15

Instruction is executed, usually by ALU.

Question 16

What is Clock Speed

Answer 16

How many cycles a CPU can perform in one second (measured in GHz)

Question 17

What is Cache?

Answer 17

Fast memory in the CPU. Stores temporary copies of data in RAM. When CPU reads data, it will first check if the address is in the cache, to determine whether to read from cache or RAM (RAM is slower)

Question 17

What are cores?

Answer 17

Processors in the CPU.
A single core can perform one instruction at a time.
Beneficial for running multiple programs at once.

Question 18

What is an input device?

Answer 18

Inputs information to be processed

Question 19

What is a sensor?

Answer 19

Detects physical qualities of surroundings

Question 20

What is an output device?

Answer 20

Outputs information so it is suitable for humans

Question 21

Primary Storage is divided into

Answer 21

RAM and ROM

Question 22

What is RAM

Answer 22

Random Access Memory is temporary storage used to access programs currently ran. It is volatile (deleted when closed)

Question 23

What is ROM

Answer 23

Contains data that can be read but not altered, not volatile (permanent)

Question 24

Why is Secondary Storage used to store data permanently?

Answer 24

It is not volatile, and does not delete upon shutdown.

Question 25

Which is larger, Secondary or Primary Storage?

Answer 25

Secondary

Question 26

How does Magnetic Storage work?

Answer 26

Uses an electromagnet to detect charges on the surface, to read / write to the storage. i.e. HDD

Question 27

How does Optical Storage work?

Answer 27

A laser is shot at the storage. If it returns to a sensor, the location is a land. If not, the location is a pit. These lands can be created to write data. i.e. CD, DVD, Blu-ray

Question 28

How does solid-state storage work?

Answer 28

Has no moving parts. Consists of transistors with NAND commands (modern) and NOR commands (older). Control gate sets transistor charge, Floating gate retains charge when power is off. i.e. Memory card, Flash Drive

Question 29

What is virtual memory?

Answer 29

Used when the computer does not have enough RAM to run a program. Pages (chunks of data) are paged out to virtual memory, until there is free space in RAM. It is secondary storage and slows down program efficiency.

Question 30

What is cloud storage?

Answer 30

Secondary storage that holds mass amounts of data in one place. It is useful if a device is broken because it can be accessed via password.

Question 31

What is local storage?

Answer 31

It is storage directly on the device / another device. It is more private, however more prone to being lost.

Question 32

What is a Network Interface Card?

Answer 32

Allow a computer to connect to a network. Often contain an ethernet port.

Question 33

What is a MAC address?

Answer 33

A 48-bit hexadecimal number associated to a device. Holds the device model and the unique device ID. i.e.
6F:5D:41:AC:23:FF

Question 34

What is an IP address?

Answer 34

A temporary or permanent address assigned to a network.

Question 35

Describe IPv4 addresses

Answer 35

32 bits long. i.e. 200.67.53.43

Question 36

Describe IPv6 addresses

Answer 36

128 bits long, hexadecimal, 7 4-character parts separated by colons.

Question 37

What are routers?

Answer 37

Hardware used to connect devices to a Local Area Network. Can connect multiple LANs to form a Wide Area Network. Send data to the correct destination on a network.