CS 1.3 Flashcards

1
Q

Give 2 reasons why a computer programmer would prefer to write a number in hexadecimal rather than binary.

A

-Easy to convert to/from binary as 4 bits per hex character.

-more reliable to
communicate

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2
Q

Describe how text is represented in a computer.

A

Each character has a unique binary value.

The binary of each character is
stored in order.

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3
Q

What is a character set?

A

It stores all the characters a computer can represent.

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4
Q

Name two character sets. Compare them.

A

ASCII + Unicode. ASCII is 8 bit so stores 256 characters. Unicode is 16 bit so supports 65,536 characters – this means files are larger but can support more languages.

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5
Q

Describe how an image is represented in a computer.

A

Images are made of pixels. Each pixel has a binary code that represents the colour. Each colour has a different binary value.

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6
Q

Describe how a sound is represented in a computer.

A

Sound wave is sampled. Amplitude is measured at set intervals. Sample stored in binary. Samples are stored sequentially.

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7
Q

what is Amplitude

A

The height of the wave – what is sampled.

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8
Q

what is Bit depth

A

The number of bits per sample.

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9
Q

what is Sample rate

A

The frequency of sampling.

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10
Q

what does change in bit depth effect

A

Bit depth = number of bits per sample. Increasing it will increase the accuracy of each sample but increase the file size.

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11
Q

what does change in Sample rate effet

A

Sample rate = how frequently the sound is sampled. Increasing increases overall accuracy but increases file size.

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12
Q

what does change in duration of a sound effect

A

higher duration = higher file size

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13
Q

Give examples of what the metadata of an image can contain.

A

Colour depth

Resolution

Height / width

Location

Date

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14
Q

what is resolution

A

Number of pixels in the image. Height * width.

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15
Q

what is colour depth

A

Number of bits used per pixel, represents the number of different colours that can be used.

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16
Q

what is a pixel

A

The smallest part of an image. Each pixel has a binary value

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17
Q

describe the need for compression

A

Compression reduces the size of a file. Makes it faster to send online and uses less space

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18
Q

What is a network?

A

A network is two or more computing devices connected together to share resources and exchange information

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19
Q

what are the Advantages of networks

A

Sharing resources
like printers and
files

Centralised
backups and
updates

Easier
communication
between users

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20
Q

what are the disadvantages of networks

A

Can be expensive
to set up

Security risks if not
properly protected.

Malware can
spread easily.

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21
Q

give characteristics of LAN

A

Network over a small geographical area

User owns the hardware

22
Q

give characteristics of WAN

A

Network over a large geographical area

Uses 3rd party hardware

23
Q

how does number of users effect network performance

A

Increased number of users means less bandwidth per user and higher latency leading to lower performance.

24
Q

how does transmission media effect network performance

A

Copper slower than fibre-optic.

Wireless is less reliable and slower than wired.

25
Q

how does latency effect network performance

A

latency is how much time it takes for a reply to be received. High latency means lower performance.

26
Q

how does bandwidth effect network performance

A

bandwidth is how much data can be transferred at once. so higher
bandwidth means higher performance.

27
Q

how does error rate effect network performance

A

error rate is Number of errors in the transmission (eg due to wireless
interference). so higher error rate means lower performance.

28
Q

what is the task performed by the Wireless Access Point

A

Allows wireless devices to communicate. Sends and receives Wi-Fi.

29
Q

what is the task performed by the router

A

Connects networks.
Receives packets.
Forwards packets using IP addresses.

30
Q

what is the task performed by the switch

A

Connects devices in a network. Sends data using MAC addresses.

31
Q

what is the task performed by the NIC

A

Gives each device a MAC.

Allows computer to connect to network.

32
Q

what is the task performed by and what is the what is the transition media

A

Carries data from one device to next.

Connects wired devices to network

33
Q

Describe what is meant by a server.

A

A computer that processes requests,
manages clients,
centrally stores files

34
Q

Identify four types of servers.

A

Web server

Mail server

File server

Gaming server

35
Q

Describe what is meant by the cloud.

A

It is accessing hardware & software that is stored remotely
instead of locally.

36
Q

advantages of star network

A

Easy to add a device.

Failed device doesn’t
impact the network.

Fewer cables so cheaper

37
Q

disadvantages of star network

A

Reliant on a central switch

38
Q

Compare two modes of wireless connection.

A

Wi-Fi & Bluetooth.
Bluetooth shorter range eg for
headphones. Wi-Fi longer range and higher bandwidth.

39
Q

what is encryption

A

Scrambling data from plain text to cipher text using a key do it cannot be read

40
Q

what is a protocol

A

A set of rules for communication between devices on a network

41
Q

what is an ip adress

A

Internet Protocol address – used to identify devices on a WAN.

42
Q

what is a mac address used for

A

Used to identify devices on a LAN.

43
Q

what is HTTP / HTTPS used for

A

Used to access websites. HTTPS uses encryption so more secure

44
Q

what is FTP used for

A

Transferring files from a client to a server.

45
Q

what is POP used for

A

Retrieves emails from a mail server.

46
Q

what is IMAP used for

A

Retrieves a copy of an e-mail to your computer.

47
Q

what is SMTP used for

A

Used to send emails

48
Q

Describe what is meant by layers.

A

A division of network functionality.

49
Q

Explain 2 advantages of using network layers.

A
  1. One layer can change without
    impacting other layers.
  2. Hardware can be designed for a specific layer.
50
Q
A