Programs usually work with data in at least two different representations:
- In memory representation: In memory, data is kept in objects, structs, lists, arrays, hash tables, trees, and so on. These data structures are optimized for efficient access and manipulation by the CPU.
- Data on file and data over the network: When you want to write data to a file or send it over the network, you need to convert it as a self-contained sequence of bytes.
