Computer science key words

Question 1

What is the Internet?

Answer 1

A collection of devices that are connected through a system of routers and servers.

Question 2

What is the WWW?

Answer 2

A collection of websites and web browsers

Question 3

What is HTTP & what does it do?

Answer 3

Safety protocol, it transfers data between a client and a server in plain text.

Question 4

What is HTTPS & what does it do?

Answer 4

Safety protocol, it uses encryption to protect data as it transfers between a client and a server.

Question 5

What is digital currency?

Answer 5

Money that only exists online

Question 6

What is a blockchain?

Answer 6

A digital ledger that records every transaction made in a specific digital currency.

Question 7

What is the concept of decentralisation?

Answer 7

When something is not controlled by central authorities.

Question 8

What are cookies?

Answer 8

Small text files that store data.

Question 9

What are the functions of the WWW?

Answer 9

1) to render html
2) record user history
3) to store cookies

Question 10

Purpose of the CPU

Answer 10

To fetch, decode, and execute

Question 11

Function of the MAR

Answer 11

stores the address of the data to be fetched or written to the memory

Question 12

Function of the MDR

Answer 12

Holds the data that has been fetched or written to the memory

Question 13

Function of the CIR

Answer 13

Stores the current instruction the CPU is decoding or executing

Question 14

Function of the Program Counter

Answer 14

Stores the address of the next instruction to be fetched from the memory.

Question 15

Function of the Accumulator

Answer 15

Temporarily stores the results of the calculations that have been performed by ALU (Arithmetic Logic Unit)

Question 16

What is a register?

Answer 16

small amounts of high-speed memory that is contained in the CPU.

Question 17

Function of the Control Unit

Answer 17

to send control signals to different components instructing them on what to do

Question 18

Function of the ALU (Arithmetic Logic Unit)

Answer 18

Performs calculations that are required to do, in order to execute instructions.

Question 19

Function of ROM

Answer 19

To store the instructions the computer executes when it is turned on.

Question 20

Function of RAM

Answer 20

To store data, instructions, and software.

Question 21

Difference between ROM and RAM

Answer 21

ROM is non-volatile.

Question 22

How does a computer fetch, decodes, and executes instructions?

Answer 22

1) Program counter check for the address of the next instruction to be executed.
2) The contents of the Program Counter will then be copied into the Memory Address Register.
3) The control unit sends a memory read request to the main memory through a control bus.
4) The address is sent through an address bus from the Memory Address Register to the main memory.
5) The contents of the Main memory will be sent down through a data bus into the Memory Data Register.
6) The contents of the MDR will be then copied into the current instruction register.
7) The CIR then inspects and decodes the instruction.
8) The instruction is then carried out by the ALU performing a calculation or storing the information back into the main memory.

Question 23

Primary storage

Answer 23

Storage that is directly accessible by the CPU.

Question 24

What is primary storage made of

Answer 24

made of RAM, Cache, and ROM

Question 25

What is Cache

Answer 25

small amount of memory that is situated near the CPU.

Question 26

What is secondary storage

Answer 26

Storage that is not directly accessible by the CPU, used for permanent storage of data

Question 27

How do Hard Disk Drives work

Answer 27

There are plates that spin at a high speed, a read or write arm is controlled by an actuator. The actuator head is moved towards the location of the data, and the data is written or read to by electromagnets.

Question 28

How do Solid State Drives work

Answer 28

Made of transistors, uses NAND and NOR gates to control the flow of electrons

Question 29

How do Optical storage (CD'S) works

Answer 29

A laser is shined at the disk and processing the reflection, an arm moves the laser across the disk. The laser burns the data into pits and lands. the laser is also used to read the data. When the laser shines where the pit changes into land or vice versa, this indicates a change in binary value.

Question 30

What is virtual memory

Answer 30

secondary storage is used to act as RAM

Question 31

What is Page Switching

Answer 31

Data than needs to be accessed by the CPU is switched by the operating system from virtual memory into ram and an inactive page from RAM replaces it in virtual memory.

Question 32

What is Cloud storage

Answer 32

method of data storage where data is stored on remote servers.

Question 33

3 types of Cloud storage

Answer 33

Public, Private, and Hybrid

Question 34

What is public cloud storage

Answer 34

Customer and storage provider are different companies

Question 35

What is Private cloud storage

Answer 35

Storage provided by a dedicated environment behind a company firewall, customer/company are integrated and act as a single entity.

Question 36

What is Hybrid cloud storage

Answer 36

Combination of Public and Private: sensitive data will be stored privately, whereas less sensitive data will be stored in a public cloud storage provider.

Question 37

NIC

Answer 37

connects a device to a wired/wireless network

Question 38

what do NICS contain

Answer 38

MAC - generated at the manufacturing stage

Question 39

MAC address

Answer 39

used to route frames on a local area network

Question 40

2 features of MAC addresses

Answer 40

1. address is unique to every NIC 2. MAC is static

Question 41

IP address

Answer 41

used to route packets on a wide area network

Question 42

feature of IP addresses

Answer 42

not always static

Question 43

Difference IPv4 and IPv6

Answer 43

IPv4 made of 32 bits and IPv6 made of 128 bits, so IPv4 cannot generate enough unique static addresses.

Question 44

Router

Answer 44

Sends data between networks

Question 45

2 jobs of a router

Answer 45

1. use devices IP address to route traffic to other routers 2. can assign IP addresses to devices on a local network.

Question 46

Virus

Answer 46

simple program made to harm the user's computer

Question 47

pharming

Answer 47

malware being downloaded on a user's device without the user knowing

Question 48

Phishing

Answer 48

sending emails that appear to come from a reliable source and try to get a users confidential information.

Question 49

Pre-condition loop

Answer 49

while loop - while a condition is true

Question 50

Post-condition loop

Answer 50

Repeat..... until loop - repeats until a condition is true

Question 51

Count-controlled loop

Answer 51

Repeats a loop a set number of times

Question 52

Normal data

Answer 52

all values are accepted

Question 53

Boundary data

Answer 53

Accepted -> upper and lower limits of the accepted range. Rejected -> values outside of the range

Question 54

Extreme data

Answer 54

Upper and lower limits of the accepted range

Question 55

Abnormal data

Answer 55

Values that are outside of the range / different data type

Question 56

Validation

Answer 56

when the computer checks if the data that has been inputted is reasonable

Question 57

Verification

Answer 57

checking the data has been accurately copied from one source to another.

Question 58

example of validation

Answer 58

Length check, validation check, type check

Question 59

example of verification

Answer 59

when a user manually verifies the data.

Question 60

why is it important for a programmer to use both validation and verification methods

Answer 60

Helps the programmer easily identify mistakes within their program.