Data Representation Flashcards

1
Q

base of denary

A

10

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2
Q

base of binary

A

2

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3
Q

base of hexadecimal

A

16

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4
Q

why do computer systems use hexadecimal

A

Hexadecimal is easier for humans to understand than binary, as it is a shorter representation of
the binary. It is used to represent colour and simplify binary

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5
Q

how to converted negative binary (two’s complement) to denary?

A

add all as normal and add result from -128

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6
Q

what happens when you shift one left

A

number multiplies by 2

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7
Q

what happens when you shift one right

A

number divides by 2

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8
Q

what does ASCII stand for

A

american standard code for information interchange

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9
Q

how many bits does ASCII have

A

7 - represents 128 characters

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10
Q

how many bits does ASCII extended have

A

8 - represents 256 characters

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11
Q

how many bits does unicode use

A

8 to 32 bits (larger files occupy more space)

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12
Q

available character sets in unicode

A

letters, numbers, symbols, emojis non-visual

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13
Q

why is a sound wave sampled

A

to be converted to binary

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14
Q

what is sampling

A

process performed by computer to convert analogue to digital waves

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15
Q

if more analogue waves are sampled…

A

….more data is gathered

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16
Q

what are analogue waves compared to digital

A

analogue = continuous
digital = discrete

17
Q

what is sample rate

A

number of samples taken in a second

18
Q

what is sample resolution

A

number of bits per sample

19
Q

how does accuracy of recording and file size increase

A

as sample rate and resolution increase

20
Q

what is an image

A

series of pixels that are converted to binary, which is processed by a computer

21
Q

what is bit depth

A

how many bits are used to store the colours in each pixel of the image

22
Q

what is resolution

A

number of pixels in image

23
Q

what is colour depth

A

number of bits used to represent each colour

24
Q

file size and quality of image increases as

A

the resolution and colour depth increases

25
measurements for data storage
- bits - nibble (4 bits) - bytes (8 bits) - kibibyte (1024 bytes) - mebibyte (1024 kibibytes) – gibibyte (GiB) – tebibyte (TiB) – pebibyte (PiB) – exbibyte (EiB)
26
what does compression do
reduces size of file
27
what is lossless compression
reduces file size without permanent loss of data
28
example of lossless compression
run length encoding (RLE)
29
what is lossy compression
reduces file size by permanently removing data
30
example of lossy compression
reducing resolution of colour depth
31
reasons for data compression to occur
- save storage capacity - speed up file transfer - decrease cost for hardware
32
How and why do computers use binary to represent all forms of data
* Any form of data needs to be converted to binary to be processed by a computer * Data is processed using logic gates and stored in registers
33
Concept of overflow and why it occurs in binary addition
* An overflow error will occur if the value is greater than 255 in an 8-bit register * A computer or a device has a predefined limit that it can represent or store, for example 16-bit * An overflow error occurs when a value outside this limit should be returned
34
How and why are ASCII and Unicode used
* Text is converted to binary to be processed by a computer * Unicode allows for a greater range of characters and symbols than ASCII, including different languages and emojis * Unicode requires more bits per character than ASCII