data representation

data representation

1. binary logic

   • logic diagrams
     • what are logic diagrams: these are diagrams which show us the three types of gates, the and gate which need two 1s to be on, the or gate which only requires one 1 to be on and the not gate which flips the on to off or off to on.
   • truth table
     • what is a truth table: a truth table is a table of results which show the possible outcomes of the gates
   • why is it in this form
     • it is in this form as a computer finds it simpler to understand binary and works well in base 2

2. units

   • files and data are measured by there size this goes up gradually, the smallest amount is a bit, four bits make a nibble, two nibbles make a byte and so on, things such as terrorbytees are 1000 gigabytes

3. data needs to be converted in to binary to be read by the computer, it does this by using on and off ports, a computer cannot understand complexe human language and so binary is used to create the values instead

4. overflow is caused when there are too many digits and a piece of code is left over, to solve the problem you must get more memory or bytes

5. hexidecimal numbers are used to bridge the gap between human and computer language by working in a higher base, this makes it esier for a human to understand

6. characters

   • binary can represent characters as different characters would have a different set of code allocated to them
   • a character set is a combination of characters, examples of this are there are smaller character sets for english keyboards than a russian one due to a increase in letters
   • asci and unicode are both examples of character sets however, they do different things, unicode is much larger than ascii as it has to contain more characters for the multiple places around the world where as ascii only needs the english alphabet

7. pictures

   • colour depth is the amount of shades the image has, higher colour depth will give a more accurate image however, it can increase the file size dramtically
   • meta data is where all the pictures most important information is stored, this helps make it easier when searching or backing up files

8. sound

   • the sample rate is how often the music is taken, higher rates mean more sounds are recorded and a more crisp noise is heard back
   • higher sample rates will lead to a better file but it will also mean the file is larger making it take longer to proccess or download

9. instruction take place in a computer with different options for example a computer would check IF no water in kettle, biol water