Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Computer science > Unit 1 - Data representation > Flashcards

Unit 1 - Data representation Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What is binary?

A

The code that computers and machines use to process information. It is composed of a number system that only uses 2 numbers (1 and 0). Usually the 0 and 1s represent “On” and “Off”.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How does a computer understand binary?

A

A computer contains a CPU which is a chip made up of millions and millions of tiny switches know as micro transistors which must be in the on or off position. The on position represents a 1 and the off position represents a 0.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why do computers use binary to represent data?

A

All information in a computer system, be it images, documents, sound, or movie files needs to be converted into the kind of data that can be represented in switches so that it can be understood and worked on by the computer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How many bits in a byte?

A

8 bits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the number 10011010 in denary?

A

1 x 128 + 1 x 16 + 1 x 8 + 1 x 2 = 154 denary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the four different uses for hexadecimal?

A
  • error codes
  • MAC addresses
  • IPv6 addresses
  • HTML colour codes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why do computer scientists uses hexadecimal?

A

It is more convenient because one hex digit represents 4 binary digits. It is far more easier for humans to remember, copy and work with. For example, 16 bits of binary can be represented as 4 different digits.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the hexadecimal number system?

A

It is a number system based of 16 different digits. It involves the numbers 0 to 9 and the letters A to F. A in hex is 10 in denary and F = 15.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a MAC address and how does it differ from a ip address?

A

A MAC address (Media access control address) is a unique number that identifies the device that is connected to the internet or network.

An IP address is the location of your device on the internet, whilst a MAC address identifies the actual device.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How many bits is a MAC address usually made up of?

A

48 bits which are shown as 6 groups of two hexadecimal digits (NN:NN:NN:DD:DD:DD). The first half (NN:NN:NN:) of the digit is the identity number of the manufacturer of the device and the second half (DD:DD:DD) is the unique serial number of the device.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is an IPv6 address?

A

An IP address (Internet Protocol address) is the unique identification number given to every device that is connected to the internet. It represents the unique location on which you are connected to the internet, allowing devices all over the world to communicate with each other. When connecting to the internet, you are assigned an IP address to use for your session. This is given to you by your network or ISP.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What would happen if we didn’t have IPv6 addresses?

A

Without these unique location addresses, data could not be transmitted between devices accurately

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How is an IP address similar to a postal address?

A

You cannot expect to get letters to your home if you don’t have a postal address.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are error codes?

A

Shown as hex values which refer to the memory location of the error. This helps programmers to find and then fix problems easier.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is HTML?

A

HyperText Mark-up Language (HTML) is used when writing and developing web pages. HTML isn’t a programming language but is simply a mark-up language, it’s used for presentation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How is hexadecimal used in HTML?

A

it is often used to represent colours of text on the computer screen. All colours can be made up of different combinations of three primary colours (red, green, blue) The first 2 digits of the 6 total digits represent the amount of red, the next two is the green and the final 2 is the blue. The hashtag symbol always precedes hexadecimal values in the HTML code to show it is a colour we are referring to.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How many different colours can you used on a HTML website?

A

16,777,216 colours, 256 x 256 x 256

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the 4 rules when adding two binary numbers together?

A

0 + 0 = 0
1 + 0 = 1
1 + 1 = 10
1 + 1 + 1 = 11

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is a overflow and what happens if one occurs?

A

An overflow is where a 9th bit would generate, this is too big and wouldn’t fit in the 8-bit register. If this was to happen the program might crash or it might just ignore the extra digit and produce an unexpected result.

A computer or a device has a predefined limit
that it can represent or store, for example 16-bits, an overflow is basically when a value outside this limit should be returned.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is a logical binary shift?

A

Computers can carry out logical shifts on a sequence of binary numbers. This shift means moving binary numbers to the left or right.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is each left and right shift equivalent to?

A

Left shift: multiplying the binary number by 2
Right shift: dividing the binary number by 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What happens to the empty bit after the shift occurs and what problems can this cause?

A

The empty positions are replaced with a zero. There is a limit to the number of shifts that can be carried out if the binary number is stored in an 8-bit register

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the most significant bit and the least significant bit?

A

MSB - the number with the highest value in binary
LSB - the number with the smallest value in binary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is two’s complement?

A

It is a way of representing negative integers.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How do you determine the sign of the binary number in two complement?

A

If there is a 1 in the left-most bit this indicates that it is a negative number, if there is a 0 in this bit this indicates that it is a positive number.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are character sets?

A

Computers works in binary. As a result, all characters, whether they are letters, punctuation or digits are stored as binary numbers. All the characters that a computer can use are called a character set

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is a character code?

A

A character code is when you press a key on a keyboard, a number is generated that represents the symbol for that key. A complete collection of character codes is called a character set.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the 2 main character sets?

A
  • ASCII
  • Unicode
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

How is it possible to store letters that are inputted by the keyboard on a computer?

A

Every character on the keyboard is represented by a binary value:
- Uppercase letters (capitals) have different values from lowercase characters
- Punctuation symbols have their own character code

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What does ASCII stand for?

A

Stands for American Standard Code for Infomation Interchange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is ASCII?

A

ASCII has become the standard code, used worldwide. it encodes 128 characters into 7-bit binary codes. Characters include numbers, uppercase and lowercase letters A-Z, punctuation symbols and the space character.

32
Q

What is extended ASCII?

A

The extended ASCII code is an 8-bit character set that represents 256 different characters, making it possible to use unique characters.

33
Q

What is Unicode?

A

Unicode uses either 8. 16 or 32 bits per character, so it can represent characters from languages from all around the world. It is commonly used across the internet. As it is larger than ASCII, it might take up more storage space when saving documents.

32 bits allow for over 2 billion different characters to be stored, including the emojis.

34
Q

What are the benefits of ASCII and Unicode?

A

Unicode: allows for a greater range of characters and symbols than ASCII, including different languages and emojis.

ASCII: Unicode requires more bits per character than ASCII

35
Q

How is sound represented on a computer?

A

Sound is captured usually with a microphone and then converted into a digital signal. all data must be converted into binary in order for a computer to process it.

36
Q

How are sounds converted to digital form so that it can be stored and processed by a computer?

A
  • An Analogue to Digital Converter (ADC) is used to convert inputs to digital signals
  • A Digital to Audio Convertor (DAC) is used to convert digital signals to outputs
37
Q

How is the sound converted to digital data?

A

To convert the analogue data to digital, the sound waves are sampled at regular time intervals. the amplitude of the sound cannot be measured precisely so approximate values are stored.

38
Q

What is the sample rate?

A

The sampling rate is the number of samples taken per second - It is measured in hertz (Hz)

39
Q

What is the sample resolution?

A

The number of bits per sample (also known as bit depth)

40
Q

What does having a higher sample resolution do?

A

More bits used per sample enables the height of the wave to be more accurately measured but increases file size.

41
Q

What sample rate are CD and MP3s sampled at?

A

CD and MP3s are usually sampled at 44,100 Hz (44.1 kHz). they have a sampling resolution of 16-bits

42
Q

How is the accuracy of a sound recording increased?

A
  • The frequency or sample rate per second affects the level of detail in the digital representation. The greater the frequency, the greater the accuracy, and file size
  • As the resolution increases so does the file size and accuracy
43
Q

How is sampling used to record a sound clip?

A
  1. the amplitude of the sound wave is first determined at set time intervals (sampling rate)
  2. this gives an approximate representation of the sound wave
  3. each sample of the sound wave is then encoded as a series of binary

using a higher sampling rate or larger resolution will result in a more faithful representation of the original sound source. However, the higher the sampling rate and/or sampling resolution the greater the file size.

44
Q

How do you calculate the file size for a mono sound file?

A

File size (bits) = sample rate (in Hz) × sample resolution (in bits) × duration (in seconds)

45
Q

What are the benefits and drawbacks of using a larger sampling resolution when recording sound?

A

Benefits:
- Larger dynamic range
- better sound quality
- less sound distortion

drawbacks:
- produces a larger file size
- takes longer to transmit/download music files
- requires greater processing power

46
Q

What are 5 examples of bitmap images files formats?

A
  • BMP
  • JPG
  • GIF
  • PNG
  • TIFF
47
Q

What are bitmap images made up of?

A

Bitmap images are made up of pixels (picture elements); an image is made up of a two-dimensional matrix of pixels.

48
Q

What is a pixel and what does having more of them do?

A
  • A pixel is the smallest identifiable area of an image
  • the more pixels in an image, the closer you get to the original image
49
Q

How is each pixel in a bitmap image represented?

A

Each pixel can be represented as a binary number, and so a bitmap image is stored in a computer as a series of binary numbers.

50
Q

What is image resolution?

A

Resolution is the number of pixels that make up an image

51
Q

what is colour depth?

A

The number of bits used to represent each colour is called the colour depth.

An 8 bit colour depth means that each pixel can be one of 256 colours.

52
Q

What does changing the colour depth do?

A

It will affect the number of colours it can display

53
Q

What are pixels made up of?

A

Each pixel has a proportion of red, green and blue. From a distance, it makes up one colour

54
Q

What are the drawbacks of using high-resolution images?

A
  • It increases file size, this impacts how many images that can be stored on, for example, a hard drive.
  • It will also impact the time to download an image form the internet or the time to transfer images form device to device.
55
Q

Fill in the gaps in each of the below sentences:
A bitmap graphic is made up of __________________
Each _______ is represented in binary
The ________________________ determines the number of available colours for an image
The greater the _________ of the image, the greater the file size

A

A bitmap graphic is made up of individual pixels
Each pixel is represented in binary
The colour depth determines the number of available colours for an image
The greater the resolution of the image, the greater the file size

56
Q

What is a bit?

A

A bit is the basic unit of all computing memory storage terms and is either 1 or 0. The word come from binary digit.

57
Q

What is a byte?
How many bits is 1 byte?

A

The byte is the smallest unit of memory in a computer.
1 byte = 8 bits

58
Q

What is a nibble?

A

A 4-bit number is called a nibble - half a byte.

59
Q

What is the acronym for increasing names for memory size? What do they mean?

A

Kids Might Get To Play Eggball

Kilobytes, Megabytes, Gigabytes, Terabytes, Petabytes, exabytes.

60
Q

How many bytes in 1 KB?
What is the rule for increasing the number of bytes?

A

1000
Times by 1000 each time

61
Q

How many bytes in 1KiB?

A

2^10 or 1024

62
Q

How many bytes in 1MiB?

A

2^20 or 1048576

63
Q

How many bytes in 1GiB?

A

2^30 or 1073741824

64
Q

How many bytes in 1TiB?

A

2^40 1099511627776

65
Q

What is the rule for increasing the number of bytes from KiB - EiB?

A

You time by 1024 each time

66
Q

How do you calculate the file size of an image?

A

Image resolution (in pixels) x colour depth (in bits)

67
Q

How would you calculate the sound of a stereo sound file?

A

Sample rate (in Hz) x sample resolution (in bits) x length of the sample (in seconds) x 2 (stereo tracks send two different channels, one for each speaker.)

68
Q

What is data compression and why do we need it?

A

Sound, images, and especially movies files can be very large. It is, therefore, necessary to reduce (or compress) the size of a file for the following reasons:

  • To save storage space on devices such as the hard disk drive/solid-state drive
  • tor reduce the time taken to stream a music or video file, it will buffer, stop and start to download the information from the file
  • to reduce the time taken to upload, download or transfer a file across the network
69
Q

What are the 2 main types of data compression?

A
  • lossy
  • loseless
70
Q

What is lossy compression?

A
  • permanently removes some data
  • recreates the file using the remaining data and uses algorithms to guess the removed content
  • uncompressed data is not the same as the original
71
Q

How does lossy compression work (images for example JPGs)?

A
  • For images (example JPGs) similarly colored pixels are all made the same
  • it finds groups of repeating data and records the data only once along with the number of times it was repeated
  • when uncompressed an images file does not restore or rebuilt in its original form. Data size is reduced but image quality is compromised
  • it can reduce the resolution or color depth or sample
72
Q

How does the file size decrease will MP3/MP4s?

A
  • MP3s use audio compression to store music in ‘filename.mp3’ format.
  • these are usually 90% smaller than non-compressed music such as that on a CD
  • They use lossy compression to remove sound that the human ear cannot clearly distinguish
  • MP4 can store multimedia also, such as movies, pictures, and sound.
73
Q

What is lossless compression?

A
  • With this technique, all the data from the original uncompressed file can be reconstructed.
  • this is particularly important for files where ant loss of data would be disastrous (e,d, when transferring a large and complex spreadsheet or when downloading a large computer application)
  • lossless file compression is designed so that none of the original detail from the file is lost.
74
Q

How does lossless compression work, RLE?

A
  • Run-length encoding (RLE) can be used for lossless compression of a number of different file formats:
  • it is a form of lossless/reversible file compression
  • it reduces the size of a string of adjacent, identical data a repeating string is encoded into two values :
    - the first value represents the number of identical data items (e.g. characters) in the run
    - the first value represents the code of the data item (such as ASCII code if its a keyboard character)
  • RLE is only effective where there is a long run of repeated units/bits.
75
Q

Why use data compression?

A

smaller files = fewer packets = faster transmission
- quicker to complete
- reduces traffic over the internet
- less chance of collisions or transmission errors

  • improves download speed of video, sound (including speech used for VOIP systems), and image files
  • speeds up downloads of web pages that use images
  • reduces space on disk/servers
76
Q

What are the main differences between lossy and lossless compression?

A

Lossy:
- Lossy compression is the method which eliminate the data which is not noticeable
- in lossy compression, a file does not restore or rebuilt in its original form
- in lossy compression, data’s quality is compromised
- Lossy is used for images, audio, and video
- lossy compression is termed as irreversible compression

lossless:
- lossless compression does not eliminate the data which is not noticeable
- while in lossless compression, a file can be restored in its original form
- lossless compression doe snot compromise the data quality
- lossless compression is used for text or programs, images, and sound
- lossless compression is termed a reversible compression

Computer science (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions