Unit 2 - Information representation Flashcards

1
Q

What is a Ring Cipher?

A

It is a way to encode and decode messages, by translating letters to numbers.

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2
Q

What is a binary table?

A

It is used to translate binary signs to numbers.

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3
Q

What is 10110101 in binary?

A

181

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4
Q

What is 11111110 in binary?

A

254

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5
Q

What is 01101100 in binary?

A

108

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6
Q

What is a Kilobyte?

A

1.000 bytes, abbreviation KB

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7
Q

What is a Megabyte?

A

1.000 kilobytes, abbreviation MB

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8
Q

What is a Gitabyte?

A

1.000 Megabytes. Abbreviation GB.

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9
Q

What is a Terabyte?

A

1.000 Gigabytes. Abbreviation TB.

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10
Q

What is a Petabyte?

A

1.000 Terabytes. Abbreviation PB

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11
Q

What is Octal?

A

It is a method to abbreviate binary. It is a base-8 system with values 0-7.

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12
Q

Name a Base-8 system

A

Octal. It has 8 characters.

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13
Q

How many binary digits can one Octal translate?

A

Three.

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14
Q

What is 111 binary in Octal?

A

7

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15
Q

What is 1010 binary in octal?

A

12

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16
Q

What is 1000 binary in Octal?

A

10

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17
Q

What is Hexadecimal?

A

It is a base-16 system, 16 possible symbols. It is the preferred method to use for translating binary to decimal. It’s written in groups of two

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18
Q

How many binary digits can one Hex represent?

A

Four

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19
Q

What is 1000 in hexadecimal?

A

08 (8)

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20
Q

What is 1100 in hexadecimal?

A

0C (12)

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21
Q

What is 1111 in Hexadecimal?

A

0F (15)

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22
Q

What is 10000 in Hexadecimal?

A

10 (16)

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23
Q

What is an alternative to Hexadecimal for decoding binary?

A

ASCII

24
Q

How are digital contents of a file viewed?

A

With a Hex editor.

25
Q

What is XML?

A

Extensible Markup Language. I used in Office since Office 2007, and also used to store data. Similar to HTML but without pre-defined tags.

26
Q

What is Unicode?

A

It is similar to ASCII except ASCII only displays English characters. It is 16-bit so can represent 65.536 different symbols. There are various formats such as UTF-8 or UTF-16.

27
Q

What is Unicode used for?

A

Internet communication.

28
Q

What is VGA?

A

8-bit or 256 colours.

29
Q

What is XGA?

A

16-bit or 65.536 colours. Also known as High Colour.

30
Q

What is SVGA?

A

24-bit or 16.777.216 colours. Also known as True colour.

31
Q

What is True Colour + Alpha channel?

A

32-bit or 16.777.216 colours. The last 8 bits are not used for colour but are a separate layer for representing levels of translucency.

32
Q

How much storage is a 24-bit image at 1080p?

A

1920 1080 * 3 = 6.220.800 bytes or 6,2MB

33
Q

What does Pixelated mean?

A

Means you can see individual pixels, due to the low number of pixels in a resolution.

34
Q

What is information represented in waves?

A

It is analog. If you want to store it on a PC, it needs to be converted digitally.

35
Q

How many values does an analog wave have?

A

An infinite continuum of values.

36
Q

How do you simulate digital representations of an analog wave?

A

You do this by sampling. Waves are cut up in tiny slices and converted. Doing the same for film is slicing stills (frames)

37
Q

What is a variable?

A

It is used in programming to store smaller units of data. It is a container for information.

38
Q

What are the factors of a variable?

A
Name (how you can identify it)
Memory location (where the unit can be found in the RAM)
Type (What kind of type it is functionally)
39
Q

What is an integer?

A

A unit number without decimal points. It saves performance since no memory needs to be assigned to the decimals. A 32-bit integer goes from -2147483648 to 213748647.

int age = 0;

40
Q

What is the data type ‘Byte’?

A

It is similar to an integer but it’s 8-bits. Value ranges from -128 to 127.

41
Q

What is a float?

A

A decimal number from 3,4e – 038 to 3,4 e + 038. It’s called a float because the decimal point can float around and that float value also needs to be stored.

42
Q

What is a double?

A

A decimal number from 1,8e – 308 to 1,7e+ 308 (64 bits)

43
Q

What is the data type Char?

A

A letter, number or symbol (16-bits)

Char middleInitial = “A”;

44
Q

What is the data type Boolean?

A

True or false, it is 1 bit.

45
Q

What is the data type String?

A

It is a sequence of character info, and varies in size.

String firstName = “Joseph”;

46
Q

What is an array?

A

An ordered sequence of primitive data type. Used to have a collection of data of the same type stored in a particular order.

Int[] lottoNumbers = {5, 22, 11, 7, 16}

47
Q

What are the numbers in an array called?

A

Elements

48
Q

What is a checksum used for?

A

It is calculated and added when data is saved. When you access the data later you do the same calculation again and compare the outcomes. If it’s the same, The data is most likely uncorrupted.

49
Q

What are ways to error check storage?

A

Checksum, parity, odd parity, cycle redundancy check

50
Q

What is parity?

A

It is a method of error-checking binary data. For every 7 bits you add an 8th parity bit. A parity bit would be even or odd, counting the number of even parity bits would need to match a certain amount.

51
Q

What is odd parity?

A

It means the total number of ones in a byte needs to be an odd number. So the parity bit would be 0 or 1 depending on whether the 7 data-bits are odd or not.

52
Q

What is CRC?

A

Cyclic Redundancy Check.

53
Q

What is Cyclic Redundancy Check?

A

Similar to a checksum, but now a block of data is processed through an algorithm. The result is added to the data. After sending, the check is repeated. Since the code is always the same length this makes it a hashing algorithm.

54
Q

What is used for error detection and correction in TCP/IP?

A

Checksum
System of Acknowledgement (ACK) containing a sequence number in the header.
If a certain datagram does not get an ACK, the sender will retransmit
Broken route detection

55
Q

What is a segment in TCP/IP?

A

A piece of data to be sent.

56
Q

What is a datagram in TCP/IP?

A

A piece of data to be sent.

57
Q

What is in the TCP/IP datagram header?

A

The sender, receiver, transmission settings, a 16-bit checksum to verify the data.