Fundamentals of data representation Flashcards
What is a natural number
A whole number used in counting. In computing 0 is a natural number
What symbol represents a natural number
N
What is a rational number
Any value that can be expressed as a ratio or a fraction (Includes integer values)
What symbol represents a rational number
Q
What is an irrational number
A value that cannot be expressed as a fraction and has an endless series of non-repeating digits e.g Pi
What is an integer number
A whole number that could be positive or negative
What symbol represents integer numbers
Z
What is a real number
Any number that is natural, rational or irrational. Cannot be an imaginary number
What are ordinal numbers
Numbers used to count places in a list e.g 1st, 2nd
How does a parity bit work
If data is looking for odd parity they will look for an odd number of 1s and vice-versa for even parity
What are the drawbacks of using a parity bit
- It can only check for errors and not correct them
2. It may fail if there are an even amount of errors
What is majority voting
When the bits within a binary string are sent three times.
It will select the majority bit within the string once it has arrived
e.g 111000111 -> 111001110 - This will be corrected to the original
What is the advantage of majority voting over a parity bit
Not only checks for errors but corrects them as well due to the 2 additional bits being unlikely to change
What is a bitmap image
An image composed of pixels where each pixel is given a set binary value to represent a colour
What is a pixel
The smallest identifiable area of an image
How do you calculate image resolution
Number of pixels high * Number of pixels wide
What is image resolution
The number of pixels in an image
What is colour depth
The amount of bits assigned to each pixel
What happens when you have a high colour depth
More colours can be represented, increasing image quality
How do you work out the colour depth
2 to the power of the amount of bits
e.g 3 bits mean 2^3 so 8 colours can be represented
What is metadata
Data about data
Give examples of metadata
Filename
Date created
File type
How do you calculate minimum file size
Width in pixels * Height in pixels* Colour depth
What is digital data
All the processes carried out by a computer are digital Discrete data (Limited in detail)
