Data Representation

Question 1

How do you convert a negative denary number to a binary number?

Answer 1

1. Write the positive Binary
2. Invert all the bits
3. Add 1

Question 2

Write -17, in binary, using Two’s complement:

Answer 2

Steps 128 64 32 16 | 8 4 2 1
1. 0 0 0 1 | 0 0 0 1
2. 1 1 1 0 | 1 1 1 0
3. 1 1 1 0 | 1 1 1 1

Question 3

What does a ‘0’ signify when it is the leftmost digit in binary?

Answer 3

Postive (+)

Question 4

What does a ‘1’ signify when it is the leftmost digit in binary?

Answer 4

Negative (-)

Question 5

What are the steps to convert a binary set of numbers to denary number using twos compliment .

Answer 5

1. Look at the leftmost bit to see if it is positive or negative.
   
   1. If Negative:
      
      1. Subtract 1
      2. Invert all of the bits
      3. Write a ‘-’ sign
      4. Calculate
   2. If Positive:
      
      1. Write a ‘+’ sign
      2. Calculate
2. Add to get the denary number
3. Write denary number with correct sign.

Question 6

How do you find the range?

Answer 6

• Steps to calculate range of two’s complement
  
  1. 2 to the power of bits (2^8 = 256)
  2. Calculate range when not two’s complement
  3. Half it to find the lowest negative number
  4. Subtract 1, for the highest positive number
  5. Write the range.

Question 7

Take this with a grain of salt but…

Answer 7

The larger the mantissa, the more accurate the number stored can be. The more larger the exponent gets the magnitude of numbers being able to be stored increases.

Question 8

How many bits can ASCII store?

Answer 8

128 bits

2^(7) = 128

Question 9

How many bits can extended ASCII store?

Answer 9

256 bits

2^(8) = 256

Question 10

How many bits can Unicode store?

Answer 10

Up to 16

Question 11

What are Unicodes Pros and Cons

Answer 11

Pros:
-Can store many, many more characters than ASCII

Cons:
- More demanding than ASCII
- Requires a lot more storage

Question 12

What does resolution dependent mean?

Answer 12

It means that once the image is created the number of pixels cannot be changed

Question 13

Resolution Meaning

Answer 13

The total number of pixels in an image

Question 14

What are the Pros and Cons of Bitmapped Graphics

Answer 14

Pros:

Cons
- Bit-mapped sets pixels so making changes requires editing all pixels involved (e.g. when moving part of graphic) which is more complex.

Question 15

What is the meaning of bit depth?

Answer 15

The number of colours that can be stored in a bitmap image.

Question 16

How to calculate colours

Answer 16

2^(8)= 256
2 to the power of bit depth.

Bit Depth | Available colours
8 bits per pixel | 256
16 bits per pixel | 65356
24 bits per pixel | 16,777,216

Question 17

What is true colour?

Answer 17

A bit depth of 24 bits, the same amount of colours as humans can see.

Question 18

What is it for something to be Resolution independent?

Answer 18

• Scaling is possible without a loss in quality
• Most commonly stored in .svg file format (Scalable Vector Graphic)
• Attributes and objects can be edited independently of one another