Brainscape's Knowledge GenomeTM

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


See full index

Computer Science > Data Representation > Flashcards

Data Representation Flashcards

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

Explain why computers use binary.

A

Computers operate using logic gates, which have only 2 states, true and false

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

What is a computer made up of?

A

Billions of switches, which have an off (0) and on (1) position - this is called binary

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

How would you work out the number of possible combinations per switch?

A

You would do 2 to the power of n - with n being the number of switches

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

What are the units of data storage?

A 
Bit - 0 or 1
Nibble - 4 bits
Byte - 8 bits
Kilobyte - 1000 bytes
Megabyte - 1000 kB
Gigabyte - 1000 MB
Terabyte - 1000 GB
Petabyte - 1000 TB
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the rules in binary addition?

A

0 + 0 = 0
0 + 1 = 1
1 + 1 = 0 carry a 1
1 + 1 + 1 = 1 carry a 1

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

What is an overflow error?

A

When the result of adding two binary numbers is greater than the number of bits allowed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a binary shift?

A

A binary shift moves all of the bits in a given binary number either to the left or the right by a given number of places

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

What would a shift to the left do to a binary number?

A

multiply the number by 2 - you do 2 to the power of n (with n being the number of shifts)

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

What would a shift to the right do to a binary number?

A

It would divide the number by 2 - you would do 2 to the power of n (n being the number of shifts)

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

What is a character set?

A

A character set consists of all the letters, numbers and special characters that can be recognised by a computer system

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

How many characters does the ASCII character set include?

A

7 bits - 128 characters

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

How many characters does the Extended ASCII set include?

A

8 bits - 256 characters

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

How many characters does Unicode include?

A

16 bits - 65,536 characters

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

Explain one limitation of the ASCII character set.

A

➜ASCII uses only 7 bits so it can only represent 128 characters
➜which is not enough to represent other languages (e.g. Russian and Arabic)

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

What is a bitmap image?

A

A bitmap image is a digital image made up of pixels

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

What are pixels?

A

Pixels represent the smallest identifiable area of an image, each appearing as a square with a single colour

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

What is the colour/bit depth of an image?

A

its the number of bits per pixel

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

How do you figure out the bit/colour depth?

A 
for example:
4 colours 
4 = 2 to the power of 2
so the colour depth = 2 bit per pixel
(the power is the bit depth)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the effects of increasing colour/bit depth of an image?

A

➜More colours can be represented so quality of the image increases.
➜However, this increases the file size

20
Q

What is the resolution?

A

It is the density of pixels in the same area

21
Q

What are the effects of more pixels per inch?

A

➜It will improve the overall quality
➜Which will increase file size
➜Which makes it possible to enlarge the image without visible loss of quality

22
Q

What is metadata?

A

Metadata is the data stored in a file alongside the actual file data identifies

23
Q

What are some examples of metadata?

A

➜Date created
➜File type
➜GPS location

24
Q

What must analogue sounds be digitally recorded in?

A

binary

25
Q

What is the amplitude?

A

the height of the wave

26
Q

What is the frequency or sample rate of a wave?

A

How often the height is recorded

27
Q

What is the sample resolution/ bit depth of a wave?

A

The accuracy to which the height is recorded - which impacts quality

28
Q

What affects the file size for sound?

A

➜sample resolution

➜duration

29
Q

What is sample rate measured in?

A

Hertz

30
Q

What is the purpose of compression software?

A

Compression software uses algorithms to remove repeated or unnecessary data

31
Q

What are the advantages of compression software?

A

➜Reduces file size
➜Reduces download time - as it is a smaller file
➜Uses less download data for users on a limited tariff (online downloads)
➜Reduces space on disk/server

32
Q

Is a bitmap image compressed or uncompressed?

A

uncompressed

33
Q

What is the ending for a bitmap image?

A

.bmp

34
Q

What are some formats of lossy compression?

A

➜JPG
➜MP3
➜MPG

35
Q

What are the advantages of lossy compression?

A

➜Smallest file sizes
➜Least transmission time (smaller file leads to fewer packets)
➜Reduces Internet traffic and collisions

36
Q

What are the disadvantages of lossy compression?

A

➜Detail is permanently lost

37
Q

What are the uses of lossy compression?

A

➜Music streaming
➜Online images and videos
➜Image libraries on devices or in the cloud

38
Q

What are some formats of lossless compression?

A

➜PDF
➜GIF
➜PNG
➜ZIP

39
Q

What are advantages of lossless compression?

A

➜Original quality is preserved - no information or data is lost

40
Q

What are the disadvantages of lossless compression?

A

➜Less significant reduction in file size

41
Q

What are some uses of lossless compression?

A

➜Text documents
➜Electronic books
➜High resolution print documents

42
Q

What is decompression?

A

the process where compressed data is restored to its original format

43
Q

What is the formula for calculating the size of an uncompressed music file?

A

Sample rate x bit depth x duration

44
Q

What are lossy compression artefacts?

A

Noise at edges and blocks are digital artefacts from lossy compression

45
Q

Are digital signals discrete or continuous?

A

discrete

Computer Science (6 decks)

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