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Computer Science - 1.2 paper 1 Memory and Storage > 1.2.4 Data Storage > Flashcards

1.2.4 Data Storage Flashcards

1
Q

How to convert binary to decimal?
Convert 1001101 to decimal

A

64 32 16 8 4 2 1
1 0 0 1 1 0 1

64+8+4+1=75

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2
Q

How to convert decimal to binary?
Convert 37 binary

A

32 16 8 4 2 1
1 0 0 1 0 1
100101

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3
Q

How to convert Binary to Hexadecimal?
Convert 10101110 to hexadecimal

A

8421 8421
1010 1110
10 14
A E
AE

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4
Q

How to convert Hexadecimal to Binary?
Convert 7F to binary

A

8421 8421
0111 1111
01111111

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5
Q

How to convert Decimal to Hexadecimal?
Convert 237 to hexadecimal?

A

128 64 32 16 8 4 2 1
1 1 1 0 1 1 0 1
8421 8421
1110 1101
E D

ED

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6
Q

How to convert Decimal to Hexadecimal?
Convert 1024 to hexadecimal

A

1024 512 256 128 64 32 16 8 4 2 1
0 1 0 0 0 0 0 0 0 0 0 0
8421 8421 8421
0100 0000 0000

400

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7
Q

How to convert Hexadecimal to Decimal?
Convert DE to decimal

A

8421 8421
1101 1110

128 64 32 16 8 4 2 1
1 1 0 1 1 1 1 0
222

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8
Q

Convert 4B to binary then to decimal

A

8421 8421
0100 1011
128 64 32 16 8 4 2 1
0 1 0 0 1 0 1 1
75

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9
Q

What are Binary Addition rules?

A

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

1110
+0111
———-
(1) 0101
/overflow

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10
Q

What is Binary Shift?

A

Shows multiplication and division of binary numbers

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11
Q

0001
Shift 1 to the left x2

A

0001 = 5
0010 = 10

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12
Q

00011
Shift left twice x4

A

00011 = 3
01100 = 12

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13
Q

000011
Shift left 3 times x8

A

000011 = 3
011000 = 24

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14
Q

00110101
Shift left 4 times x16

A

00110101
1/1 01010000

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15
Q

00010100
Shift right once /2

A

00010100 = 20
000001010 no 0 = 10

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16
Q

00010100
Shift right twice /4

A

00010100 = 20
00000101 = 5

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17
Q

00000101
Shift to the right once

A

00000101
00000010.1
If you lose one you do a right shift.
5-2=2 lost accuracy with the number
lose 1 = lost accuracy of the number

18
Q

What is a character set?

A
  • A character set is a table that matches together a character to a binary value
  • Character sets are necessary as they allow computers to exchange data and allow humans to input characters using a keyboard
19
Q

What is an example of a character set?

A

A = 01000001 = 65
B = 01000010 = 66
C = 01000011 = 67

20
Q

What is ASCII?

A
  • American Standard Code for Information Interchange is a common character set which doesn’t take up too much memory
  • It is important to understand that the number of characters available are limited by the number of bits available
  • ASCII uses 8 bits (1 byte) per character meaning there are only 256 possible characters to use
  • Only inclusive for english language - became outdated in the 1970s
21
Q

What is unicode?

A
  • Unicode is a more popular character set as it uses 16/32/64 bits per character
  • Unicode-16 means that 16 bits are used per character meaning there are 65536 possible characters
22
Q

What does this mean we can include in unicode with 65536 possible characters?

A
  • Different languages
  • Symbols
  • Emojis
23
Q

How do you calculate the size of a text file?

A

The file size of a text file is calculated as shown:
bits per character x number of characters

24
Q

A small text file uses the ASCII character set (8 bits per character). There are 300 characters in the file. Calculate the size of the file (answer normally in kilobyts)

A

8 x 300 = 2400 bits
/8 = 300 bytes
/1000 = 0.3KB

25
Q

What are the 2 types of images?

A

Bitmap and Vector

26
Q

What are Bitmap Images?

A
  • Bitmap images are made up of pixels - a single square assigned a colour - laid out in a grid of a certain height and width
  • Each pixel is assigned a binary value which represents the colour of that pixel
  • Because it is made up of pixels scaling a bitmap up will result in a loss of quality
27
Q

How do you improve the quality of an image?

A
  • Increasing the total amount of pixels in an image - this is known as image resolution
  • Increasing the amount of bits per colour to allow for more colours to be available - this is known as the colour depth
28
Q

What is the image resolution?

A
  • The resolution of an image is the width in pixels multiplies by the height in pixels
29
Q

How do you calculate the size of a bitmap file?

A

file size = resolution x colour depth

30
Q

An image has a height of 6 and a width of 8, colour depth = 1 bit (only two colours). What is the file size? (answer in kilobytes)

A

Resolution = height x width = 6x8 = 48 bits
File size = resolution x colour depth = 48x1 = 48 bits
file size in bytes = 48/8 = 6 bytes
file size in kilobytes = 6/1000 = 0.006 kilobytes

31
Q

What are vector images?

A
  • Drawn by the computer using precise mathematical instructions to create lines and objects
  • Usually smaller in file size compared to bitmaps
  • Vector images can be scaled up without any loss of quality and typically used for logos and animations
32
Q

What is Metadata?

A

Additional data that a computer has on an image is called metadata and can include the following:
- resolution
- colour depth
- geolocation
- date created
- last edited
- file type
- author details

33
Q

What is sound?

A

Singing, tapping, an alarm going off, these are all sounds that we maybe able to hear. When we visualise this sound it is usually an analogue sound

34
Q

How do you convert analogue to binary?

A
  • The analogue sound wave needs to be converted to store the sound in binary. This is called analogue to digital conversion (ADC)
  • The amplitude (height) of the wave is measured and recorded in binary at specific intervals (sample rate).
35
Q

What is the sample rate?

A
  • Sample rate / sampling frequency is the number of times per second the amplitude of the sound wave is measured in kilohertz (KHz)
36
Q

What is the sample rate impact?

A
  • The higher the sample rate, the better the audio quality as the digital data more closely resembles an analogue wave
  • However, the higher sample rates mean a larger file size because more data is stored for each individual sample
37
Q

What is Bit Depth?

A
  • Bit depth is the number of bits available to represent each sample
  • For example, a sample with a depth of 4 could mean 0011 or 0100. A sample with a bit depth of 8 could be 01001001. A common bit depth is 16
  • Having a lower bit depth reduces the amount of sounds that can be captured
38
Q

What is the impact of bit depth?

A
  • The higher the bit depth, the more bits are available to be used for each sample. Therefore the quality of the audio is often higher as the wave closely resembles the analogue wave.
  • However this will also increase the file size as each sample stores more bits
39
Q

How do you calculate the size of a sound file?

A

sound file size = sample rate x bit depth x duration

40
Q

A sound file has a bit depth of 4, a sample rate of 10 samples per second and the clip is 15 seconds long. What is the size of the sound file?

A

sample rate x bit depth = 4 bits x 10 = 40 bits

length of the clip = 40x15 = 600 bits

bytes = 75 KB = 0.075 MB = 0.000075

Computer Science - 1.2 paper 1 Memory and Storage (5 decks)

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