The term data virtualization is based on the word virtualization. Virtualization is not a new concept in the IT industry. Probably the first application of virtualization was in the 1960s when IBM used this concept to split mainframes into separate virtual machines, which made it possible for one machine to run multiple applications concurrently. Also in the 1960s, virtual memory was introduced using a technique called paging.
Memory virtualization was used to simulate more memory than was physically available in a machine. Nowadays, almost everything can be virtualized, including processors, storage , networks, data centers, and operating systems. VMWare and Cloud can also be regarded as virtualization technologies.
In general, virtualization means that applications can use a resource without any concern for where it resides, what the technical interface is, how it has been implemented, which platform it uses, and how much of it is available. A virtualization solution encapsulates the resource in such a way that all those technical details become hidden and the application can work with a simpler interface.
This API was a layer of software that would hide the user interface technology in use for the rest of the application. Without knowing it.