The theory of rough sets was founded by Zdzisław Pawlak to serve as a framework for data and knowledge exploration. Following Professor Pawlak's seminal paper titled "Rough Sets" published in 1982 in International Journal of Computer and Information Sciences*, it is important to discuss the history, the presence and possible future developments of this theory, as well as its applications. One of the key aspects that lets us use rough sets in practical scenarios is the notion of information system which in fact comes from even earlier Professor Pawlak's works. Information systems are the means for data and knowledge representation. They constitute the input to rough set mechanisms aimed at computing concept approximations and deriving compacted and interpretable decision models. Accordingly, in this paper we discuss where information systems come from. We claim that in many applications it is not enough to statically gather the data into a data set - represented as an information system - and then explore that set with no linkage to the data origins. Quite oppositely, in practice we may need to work with information systems more actively, giving ourselves a technical possibility to retrieve them dynamically, assuming interaction with physical environments where the data is created.
* In 1985, the name International Journal of Computer and Information Sciences was changed to International Journal of Parallel Programming.