Flashcards in 4. Data Representation Deck (60)

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1

## How does binary work?

### Each digit is a 0 or 1. The system works in base 2. That means each digit from right to left represents 1, 2, 4, 8, etc.

2

## What is hex short for?

### Hexadecimal

3

## How many digits are there in hex?

###
16

0 - 9 and A - F

4

## How is hex linked to binary?

### Each hex digit is equivalent to a binary nibble of 4 digits. For example, 1110 is E.

5

## How can an 8-bit binary number be written in hex?

###
Each of the two nibbles is converted to hex and then these are joined together.

For example, 1101 is D and 0100 is 4.

So, 11010100 is D4 in hex.

6

## How do you convert from hex to denary?

###
1. Convert each digit to a nibble of binary

2. Put the two nibbles together

3. Convert this to denary

7

## How do you add two binary numbers?

###
Using column addition.

0 and a 0 make 0.

0 and 1 make 1.

1 and 1 make 0 but carry 1 to the next column.

8

## What is an overflow error?

### When the processor does not have enough bytes available to process an instruction.

9

## What is a nibble?

### 4 bits

10

## What is a byte?

### 8 bits

11

## What is a kilobyte?

### 1024 bytes

12

## What is a megabyte?

### 1024 kilobytes

13

## What is a gigabyte?

### 1024 megabytes

14

## What is a terrabyte?

### 1024 gigabytes

15

## What is the order of 'bytes' in increasing size?

###
Nibble

Byte

Kilobyte

Megabyte

Gigabyte

Terrabyte

16

## What is a bitmap image?

### An image stored as a series of values per pixel. The colour of each pixel is stored in a file.

17

## What is a pixel?

### A picture element - the smallest part of a bitmap picture.

18

## What does DPI stand for?

### Dots per inch

19

## What is resolution?

### The amount of pixels in an image. Usually measured in DPI.

20

## How is binary used in a black and white bitmap picture?

### Each pixel is represented by a 0 or 1. Only two are needed because there is only black and white.

21

## What is colour depth?

### The amount of bits used per pixel to encode the colour information.

22

## How is binary used to represent pixels in a colourful image?

### Each colour is given a binary number. If there are only 4 colours then they can be represented using 00, 01, 10 and 11.

23

## What is the difference between vector and bitmap images?

###
BITMAP

• Each pixel is mapped and given a colour

• Suitable for photographs

• Quality is lost when stretched or resized

VECTOR

• Instruction for how to draw the picture are included

• Length of line, angles, curves, thickness of lines, etc.

• Best for cartoons and clip art

• Quality not lost when resized

24

## What is lossless compression?

### When a file is compressed so that picture quality remains the same and it can be decompressed into its original quality.

25

## What is lossy compression?

### When a file is compressed so that it permanently removed data. It cannot be decompressed into a file of the same quality.

26

## What does analogue mean?

### A continuously varying signal - like a car speedometer

27

## What does digital mean?

###
A discrete value (a single number)

0s and 1s in computers

28

## What does ADC stand for?

### Analogue to Digital Converter

29

## What is the sample rate?

### The number of samples taken per second.

30