data representation Flashcards

1
Q

what is binary?

A

1s and 0s that computers understand

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2
Q

size of a bit?

A

a single binary digit (1 or 0)

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3
Q

size of a nibble

A

4 bits

EG: 0101

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4
Q

size of a byte?

A

8 bits

EG: 01011101

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5
Q

size of a kilobyte?

A

1000 bytes

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6
Q

size of a megabyte?

A

1000 kilobytes

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7
Q

size of a gigabyte?

A

1000 megabytes

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8
Q

size of a terabyte?

A

1000 gigabytes

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9
Q

size of a petabyte?

A

1000 terabytes

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10
Q

order of bits (small-large)

A

Bats -bit
Nibble -nibble
Bread -byte
Knowing -kilobyte
Mice -megabite
Give -gigabyte
Terrible -terabyte
Presents -petabyte

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11
Q

what is denary?

A

standard number system
1-10

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12
Q

whats the highest binary can go?

A

255

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13
Q

how to convert from binary to denary?

A

add up the numbers with a 1 in their collumn

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14
Q

how to convert from denary to binary?

A

subtract from left to right

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15
Q

how to add binary?

A

put them into collums
start on the right add the numbers

when doing 1+1 = 10 (2) place 0 and carry 1 to the next collumn

when doing 1+1+1 = 11 (3) place 1 and carry 1 to the next column like regular addition

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16
Q

what is an overflow?

A

when a number has too many bits than a CPU is expdcting

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17
Q

what is a binary shift?

A

moves every bit in a binary number left or right

gaps on the ends get filled by 0s

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18
Q

what is a left shift?

A

multiplies the number

for every place shifted left the number is doubled

moves LEFT

19
Q

what is a right shift?

A

divides a binary number

for every place shifted right the number is halved

moves RIGHT

20
Q

what are hexadecimal numbers?

A

uses a combination of digets and letters to represent a number

21
Q

what is the highest hex number before it becomes a letter?

A

9

22
Q

converting binary to hex?

A

split into nibbles(4s)

draw table 8,4,2,1 and fill in

for each nibble(4) add up the numbers with a 1

put hex numbers together

23
Q

what is ascii?

A

a commonly used english character set

24
Q

how to work out file size?

A

number of bits per char X num of chars

25
Q

what is a bitmap image?

A

an image made of pixels represented by binary codes

26
Q

how are colours represented in pixels in photos?

A

by binary

27
Q

what is a 1bit image?

A

made of 2 colours, 1 bit for each pixel

28
Q

what is a 2 bit image?

A

made of 4 colours, 2 bits per pixel

29
Q

how to make more shades/colours in an image?

A

increase the colour depth

30
Q

what is colour depth?

A

the number of bits used for each pixel

31
Q

what is metadata?

A

the information stored in an image file which helps the computer relate the image to binary

32
Q

examples of metadata?

A

height
width
colour depth
resolution

33
Q

what is sample rate?

A

how many samples you take per second (sound)

measured in Hz

34
Q

what is data compression?

A

temporarily/permanently removing unwanted data from a file to make it smaller while keeping it as true to the original as possible

35
Q

advantages of compressing files?

A

take up less storage on a device

streaming is quicker as they take less bandwidth

emails usually have restrictions

36
Q

what are the two types of compression?

A

lossy

lossless

37
Q

what is lossy compression?

A

permanently removing data from a file, reducing its size

38
Q

what is lossless compression?

A

temporarily removing data to store the file then restores it to its original state when opened

39
Q

advantages of lossy compression?

A

greatly reduces the file size meaning more files can be stored

take up less bandwidth so can be downloaded/streamed quicker

40
Q

disadvantages of lossy compression?

A

loses data, the file cannot be turned back to its original state

cannot be used on text files as they need to keep all their information

worse quality than the origional

41
Q

file type examples for lossy compression?

A

MP3
JPEG

42
Q

advantages of lossless compression?

A

there is no reduction in quality as data is only temporarily removed

can be turned back to its original state

can be used on text files

43
Q

disadvantages of lossless compression?

A

only a slight reduction in file size so it still takes up space on your device

44
Q

file type examples for lossless compression?

A

PNG
ZIP