Brainscape's Knowledge GenomeTM

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


See full index

Computing > Data > Flashcards

Data Flashcards

1
Q

name the order of units from smallest to biggest (bytes)

A 
bits
nibble
bytes
kilobytes
megabytes
gigabytes
terabytes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

how many bytes are in 5 megabytes

A

5 x 1024 x 1024 = 5,242,880

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

explain the effect of increasing the sampling frequency for a sound conversion

A
  • more data will be converted
  • therefore increases the storage capacity for the recording
  • this will be a more accurate representation of the original recording
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

compare storing data on the cloud to on hard disks for a school

A
  • school is responsible for providing more storage as demands evolve but storage provider is responsible for providing storage on demand
  • if internet connection isnt available, cant access data on the cloud but files are available without a connection on hard disks
  • staff can access data anywhere using mobile devices on cloud but data can be only accessed in the school
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how do computers read program instructions

A
  • processors contain billions of transistors which act as switches.
  • they only have 2 states - on and off
  • there are only 2 states therefore binary is used to represent data and instructions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

how are pictures represented in binary and why

A
  • in black and white (no colours/shades) because there are only two digits used
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

write an arithmethic expression to show that 256 different colours can be represented in 8 bits

A

number of colours = 2^8 = 265 colours

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

how many colours can be represented in 6 bits

A

2^6 = 64 colours

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

how many bits does it take to represent 16 colours

A

16 = 2^4 so it takes 4 bits

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

convert 79 into binary

A

01001111

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

convert 00110110 into denary

A

54

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

convert 203 into binary

A

11001011

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

what is an overflow error

A

an overflow error occurs when a calculation produces a result that is greater than the processor can deal with

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

state an effect of using the result of the overflow error in further calculations

A

the calculations would produce inaccurate results

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

add 01011101 and 01011001

A

10110110

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

convert 10010111 into a decimal number (denary)

A

151

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

how many shifts to the left would you shift a binary number if you mulitply it by 2^4

A

4 places

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

how do you perform a logical shift (multiplying)

what effect does this have on the number

A

Left Logical muLtiply

move the digits to the LEFT and fill the gaps with 0s
multiplys the number by a power of 2 ie 2^3 is 3 shifts. number would be 8 times bigger

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

explain how a binary number can be multiplied by 8 by shifting bits

A

8 is equal to 2^3 so the bits are shifted 3 places to the left
0s should replace the 3 gaps on the left

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

multiply 01101110 by 2^3

A

01110000

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

how do you perform a logical shift (dividing)

what effect does this have on the number

A

dIvIde = rIght

move the digits to the RIGHT and fill the gaps with 0s
divides the number by a power of 2 ie 2^3 is 3 shifts. number would be 8 times smaller

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

explain why performing a logical shift of 3 places on the binary number 10110100 could result in a loss of precision

A
  • 10110100 = 180.
  • the calculation would be 180/8 = 22.5
    10110100 shifted is 00010110 (this is 22 which is less than 22.5)

this is because the answer is always given as the nearest lower integer in a right logical shift so some precision is lost

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

how do you represent a denary number in sign and magnitude

A

the leftmost big (MSB) is used to show that a number is positive (0) or negative (1) and is shown +/-
the other 7 bits show the numerical value of the number

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

convert -62 into binary

A

11000010

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

convert 62 into binary using sign and magnitude

A

00111110

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

how do you represent a denary number in twos complement

A

the leftmost big (MSB) is used to show that a number is positive (0) or negative (1) and is shown as -128
the other 7 bits are posistive
- highest denary number you can represent is 127

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

give disadvantages of sign and magnitude

A

0 can be both posistive and negative

when adding +10 and -10 the result should be 0 but it gives -20

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

give advantages of twos complement

A
  • 0 can be represented in only one way 00000000
  • calculations are always accurate
  • negative numbers can be represented
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

give disadvantage of twos complement

A

computers cannot use this number system only humans

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

give a disadvantage of sign and magnitude

A

computers cannot use this number system only humans

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

whats the highest number you can represent in bianary

A

255

to get a higher number you must add more bytes

32
Q

compare using binary to twos complement

A
  • binary can be used by computers, twos complement cannot
  • binary can represent higher denary numbers (255) than twos complement (127)
  • two complement can represent negative numbers, biary cannot
33
Q

state 2 reasons why using twos complement is preferable to sign and magnitude

A
  • 0 can be represented in only one way 00000000

- additions are always accurate

34
Q

how do you subtract in binary

A
  • turn number into its negative form by flipping all the bits (1s to 0s) and adding 1
  • add the 2 numbers together
35
Q

01000110 - 01000110

A

01000110 = 70
+ 1
10111010 = -70

10111010
+ 01000110
I NEED WORK

36
Q

how do you multiply signed binary numbers

A
  • perform arithmetic shift left
  • shift the bits LEFT and fill the gaps with 0s
  • never move the MSB as this determines the sign
  • used in sign and magnitude to multiply it by a power of 2
37
Q

perform an arithmetic shift left on -36

A

36 = 00100100
MSB stays where it is (36 is posistive)
72 = 01001000

38
Q

perform an arithmetic shift left on 36

A

-36 = 11011100
MSB stays where it is (-36 is negative)
-72 = 10111000

39
Q

how do you divide signed binary numbers

A
  • perform arithmetic shift right
  • shift the bits RIGHT and fill the gaps with copies of the MSB
  • never move the MSB as this determines the sign
  • used in twos complement to divide it by a power of 2
40
Q

perform an arthimetic shift right 3 places on 01101011 in twos completment

A

0001101

41
Q

how do you convert 10110011 into hexadecimal

A 
spilit the byte into 2 nibbles:
- 1011 = 8+2+1 = 11
11 is B
- 0011 = 2+1 = 3
B3
42
Q

What do the letters in hexadecimal represent

A 
A = 10
B = 11
C = 12
D = 13
E = 14
F = 15
43
Q

convert C3 to binary

A

split hexadecimal in 2
C = 12 1100
3 0011

11000011

44
Q

what are the uses of hexadecimal

A
  • to help humans to cope with long strings of binary digits (much shorter than binary)
  • to give error code messages when a computer malfunctions
  • to represent numerical values in assembly language (a low-level programming language)
  • used in true colour
45
Q

what is true colour

A
  • it uses 24 bits to code every available colour variation (2^24)
  • each one represented by 3 8-bit numbers, simplified to 3 hexadecimal numbers
  • this is far easier to remember & enter 6 hexadecimal digits than 24 digits of binary
46
Q

what is ascii code

A
  • a 7 bit code with 2^7 (128) code sequences
  • represents characters, numbers, text and symbols ie shift and space
  • the character set is the list of binary codes that can be recognised by computer hard/software
47
Q

what is the extended ascii code

A
  • uses 8 bits with 2^8 (256) code sequences

- includes maths symbols ie π

48
Q

what is are the disadvantages and advantages of extended ascii code

A

+ can represent more code sequences than the standard ascii code

  • data cannot be transferred across platforms accurately as it hasn’t been standardised like standard ascii code so different manufacturers use different codes for different characters
  • not enough codes to represent different languages
49
Q

how do you find different characters in ascii code

A
  • if you know lower case ‘a’ is 97 then ‘c’ is 99

- if you know upper case ‘S’ is 83 then ‘W’ is 87

50
Q

how do you return ascii code in PYTHON pseudocode

A
  • ord(‘c’) returns 99
  • chr(100) returns ‘d’
  • cannot do this in edexel pseudocode
51
Q

the character at index (2) returns the number 99 and index(3) returns 101
what numbers would be returned at index (8)

A

110

52
Q

what is a pixel

A

short for picture element.

  • a digital image composed of many small points of colour
  • each pixel has its indivudual colour
  • the greater the number of pixel, the greater the detail in the picture
53
Q

how do you write the size of an image

A

width x height

ie 300 x 1000

54
Q

what is colour depth

A

the number f bits used to encode the colour of each pixel
- the more bits used to encode the colour the greater of actual colours that can be representted in the images. image is more detailed

55
Q

what colour depth do modern cameras and spartphones use

A

24-bit colour depth = 2^24 colours

56
Q

how do you work out the image file size

A

width x height x colour depth (IN BITS)

  • the better the image quality the larger the file size
  • large file sizes can be problematic when sending them electronically or when storage space is limited
57
Q

what is the resolution of an image

A

the number of pixels per inch when the image is displayed

58
Q

what happens if a small image becomes enlarged

A
  • it is less sharp as there are less pixels per unit of area and each pixel has to be enlarged
  • therefore image has a lower resolution
  • if it is enlarged too much it becomes pixelated meaning individual pixels can be seen
59
Q

contruct an expression to calcuate the file size in MB of a 24 bit image with the dimensions 410 x 270

A

convert into MB

(41027024)/8/1024/1024

60
Q

describe what factors affect the quality of a digital image

A
  • the number of pixels that make the image up
  • an image of 5000 x 3000 will have a better resolution than an image with size 640 x 480 pixels
  • number of bits used to encode the colour of each pixel is called colour depth. if more bits are used, more colours can be displayed
  • if more colours are used then v. small colour changes can be represented in the image, increasing the detail
61
Q

how are all images represented in computers

A

strings of 1s and 0s

62
Q

how is sound represented in digital form

A

strings of 1s and 0s

63
Q

describe how an analogue recording is performed

A
  • sound is caused by vibrations travelling through a medium ie air or water
  • sound recordings convert the changes in air pressure into voltage changes
64
Q

what is the sampling frequency

A

how many samples of a sound wave are taken per second (measured in Hz)
- a high sampling frequency gives a more accurate reproduction of the analogue waveform

65
Q

what is a sample in sound recording

A
  • snapshots of the sound at regular fixed intervals. these samples are played back one after the other, known as a digital recording
  • digital recordings cant continuously reproduce analogue changes since transistors can only be on or off
66
Q

what is the bit depth/resolution of a sound recording

A

the number of bits used to encode each sample

  • high bit depth allows more data to be stored and allows the dynamic range of the sound to be more accurately represented
  • 8 bits allows 2^8 graduations of volume
67
Q

what is the sampling frequency for CDs

A

44100 Hz

68
Q

what is the sampling frequency for bluray audio

A

96000 Hz

69
Q

how do you convert from bytes to KB

A

x 1024

70
Q

how do you convert from MB to TB

A

x 1024 x 1024

71
Q

how do you calculate audio file sizes

A

file size (BITS) = sample freq x bit depth x recording length (SECONDS)

  • higher the sample freq and bit depth larger the file size
  • if storage availability is low, lower sample rates must
72
Q

what happens if storage availability is low for sending for storing audio files

A
  • lower sample rates must be used, lowering the accuracy of the digital representation of the analogue signal and lowering the quality of the recording
73
Q

what is KHz equal to in Hz

A

1000Hz

74
Q

construct an expression to caculate the size in MB of a digital audio file of 3 minutes with a sampling frequency of 44.1 KHz and resooution of 16 bits

A

convert units

(44100 x 180 x 16)/8/1024/1024 MB

75
Q

how do you convert from bits to MB

A

x 8 x 1024 x 1024

76
Q

contruct an expression to calculate the file size in MB of a stereo audio file if duration is 2 mins 30 secs and sampling freq is 44.1KHz with bit depth of 16 bits

A

(150 x 44100 x 16 x 2)/ 8/ 1024/ 1024

stereo recordings have 2 channels therefore total file size must me DOUBLED

Computing (6 decks)

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