2.6 Data Representation

2.6 Data Representation

1. Bitmap

   • the page is divided into an invisible grid and each pixel is assigned a colour
     • the image is not as clear and takes up more room

2. Vector

   • Drawn a following set of mathematical instructions
   • They never get blurred and less room

3. ASCII - American Standard Code for Information Interchange

   • used to allow the computer to understand characters that have been typed in by a human
   • Extended ASCII uses 8 bits and can use more characters

4. Hexadecimals are used because;

   • Binary produces long strings and can be difficult to work with. Hex is shorter
   • Hex can be easily converted to/from binary as there is 1 hex digit per nibble
   • Hex is less susceptible to error
   • Programmers prefer to use hex as it is less to use for them

5. Unicode was developed to account for every language in the world

6. Metadata- certain information must be identified for the bitmap image. Holds data in the background such as data,place,time,size etc.

7. Digital audio

   • The quality that the samples are stored with depends on different factors;
     • Sample frequency
       • The number of audio samples captured every second
     • Sample size
       • number of bits available for each sample
     • Bit depth
     • Bit rate
       • The number of bits used per second of audio

8. Data compression is the process of encoding data so that needs fewer bits/bytes to represent it. It is useful as it helps reduce the consumption of expensive resources, such as hard disk space.

9. Lossy- when you compress, you don't lose any information

   • Advantages can produce smaller data files
   • Disadvantages is that no good if 100% accuracy required e.g. text files

10. Bit

    • is a binary digit
    • it is the smallest unit of data a computer can store
    • each 'bit' is represented using either 1 or 0

11. Nibble

    • Describes 4 bits
    • it is really useful when converting between binary and hexadecimal

12. Byte

    • Collection of 8 bits
    • is the building block for every other measurement

13. Kilobyte

    • it can be thought of as 1,000 bytes

14. Megabyte

    • Most common unit of storage
    • used to measure transmission speeds on the web and storage space on a CD