2.5 Data Representation Flashcards Preview

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Flashcards in 2.5 Data Representation Deck (26)
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1
Q

What is the order of data size?

A
Bit - single digit (0 or 1)
Nibble - 4 bits 
Byte - 8 bits 
Kilobyte - 1024 bytes 
Megabyte - 1024 KB 
Gigabyte - 1024 MB 
Terabyte - 1024 GB 
Petabyte - 1024 TB
2
Q

How do computers understand binary?

A

They don’t understand the numbers 1 and 0, they understand flashes of electricity that pass through the transistors.
1 = Electricity pulse
0 = No electricity pulse

3
Q

What number system is binary?

A

Base 2:

2 possibilities - 1 or 0).

4
Q

Define vector

A

An image drawn by a set of mathematical formulas and can be scaled infinitely without any loss in quality.

Every line and shape has a value that changes when the image expands.

5
Q

Define bitmap

A

Page is divided into an invisible grid and each pixel is assigned a colour in binary (colour depth).

Higher bit depth = Higher image quality.

6
Q

What is PPI and DPI?

A

Pixels per inch.

Dots per inch.

7
Q

What happens if a pixel is to represent more than 1 colour?

A

We need to use more bits to make a range of colours available.

8
Q

How do you find out how many bits represent colours?

A

2 to the power of the number of bits = number of colours.

1 bit = 2 colours.
2 bits = 4 colours.
3 bits = 8 colours.

9
Q

What happens with greater colour depth?

A

The more:
Realistic colours there are
Data needs to be stored.
File size on the disk is needed.

10
Q

What happens with higher resolution?

A

There are more pixels, higher quality and higher image file size.

11
Q

What is digital sound broken down into?

A

Thousands of samples per second - each of which are stored as binary data.

12
Q

What does the quality of the samples depend on?

A

1) Sample frequency.
2) Sample size / bit depth.
3) Bit rate.

13
Q

Define sample rate

A

No. of audio samples captured every second.

14
Q

Define analogue

A

Made up of a variation of dynamic and frequencies.

15
Q

Define sampling

A

Recording snippets of sounds at set intervals.

16
Q

Define character set

A

The possible characters that can be represented in a computer system.

E.g. ASCII and Unicode.

17
Q

Define metadata

A

Image data that allows the computer to recreate the image from the binary data in the file.

Examples: 
Dimensions. 
Number of bits per pixel. 
Location. 
Data and File type.
18
Q

Define image size

A

Width and height of a bitmapped image, measured in pixels.

19
Q

If an image has its colour depth increased what is the effect?

A

The file size is bigger.

20
Q

Define overflow error

A

When the binary number is too big than actually possible

21
Q

What are the hexadecimal numbers compared to denary numbers?

A
A = 10
B = 11 
C = 12 
D = 13 
E = 14 
F = 15
22
Q

Define lossy compression

A

The file is compressed and data is lost. It compresses more than lossless

Should be used in audio files.

23
Q

Define loseless compression

A

The file is compressed; no data has been lost (file size is just smaller, but it isn’t as compressed as lossy ).

Should be used in text documents.

24
Q

What is the effect of multiplying the binary number by 2?

A

The number is shifted to the left by 1 bit

25
Q

What is the effect of dividing a binary number by 2?

A

The number is shifted to the right by 1 bit

26
Q

Define underflow

A

When the binary number is too small than actually possible