A data system is a term used to refer to an organised collection of symbols and processes that may be used to operate on such symbols [1][2]. Any organised collection of symbols and symbol-manipulating operations can be considered a data system. Hence, human-speech analysed at the level of phonemes can be considered a data system as can the Incan artefact of the khipu and an image stored as pixels. A data system is defined in terms of some data model and bears a resemblance to the idea of a physical symbol system.
Symbols within some data system may be persistent or not. Hence, the sounds of human speech are non-persistent symbols because they decay rapidly in air. In contrast, pixels stored on some peripheral storage device are persistent symbols.