Data representation

Question 1

Character set

Answer 1

The defined list of characters recognized by a computer’s hardware and software
e.g. ASCII

Question 2

What is ASCII and its types

Answer 2

ASCII- American Standard Code for Information Interchange is a character set
ASCII code provides a industry standard so data will be interchangeable between computers from different manufacturers
Standard and Extended ASCII
It represents all the lowercase and uppercase letters, punctuation marks and control actiona

Question 3

Standard ASCII

Answer 3

7 bits
2^7 =128 characters could be represented
eg:
65-90=A to Z
97-122=a to z
48-57=0 to 9

Question 4

Extended ASCII

Answer 4

8 bits
2^8=256 characters could be represented
Many versions are available
Grouped according to function

Question 5

Unicode

Answer 5

Problem with extended ASCII is that there were too many versions and no standardization
Different manufacturers such a IBM Apple created their own version with different characters represented by the same code
Also the 256 combinations were not enough to represent all language alphabets in the world
Unicode consortium was founded to develop and promote a unicode standard which uses 2 bytes (16 bits) or 4 bytes (32 bits) giving a 2^16 or 2^32 combination
0 to 127 are the same as ASCII
This has become the universal standard used by major hardware and software manufacturers and can represent characters in all known languages

Question 6

Representation of bitmap images

Answer 6

Images stored as binary codes

Question 7

Pixel

Answer 7

Picture element stored as a single bit
The basic smallest single point of colour in a graphic image.
Basic unit in a graphic image

Question 8

Resolution

Answer 8

Number of pixels per inch when the image is displayed on a monitor or on paper
The greater the number of pixels in a given area the higher the resolution and quality
Resolution=Width*Height

Question 9

What is colour depth

Answer 9

Number of bits used to encode the colour of each pixel
It decides the number of colours that can be represented
1 bit= 2^1 - 2 colours- monochrome (black and white)
2 bit= 2^2 - 4 colours
3 bit= 2^3 - 8 colours
8 bit= 2^8 - 256 colours

Question 10

true colour

Answer 10

Shows life like images
It can represent the colour of each pixel in 24 bits that is 8 bits for each primary colour
256 variations for each colour
RedGreenBlue= 2^8 * 2^8 2^8 = 256256*256

Question 11

File size

Answer 11

File size=Width * Height * Colour depth

Question 12

File size

Answer 12

File size=Width * Height * Colour depth