In the most technical sense of the term, anything that abstracts the physical storage from the operating system that addresses it could be considered a form of storage virtualization. A simple example can be found in the file system that your hard disk is formatted with. When you open any file on your computer, it performs a lookup in your file system's file allocation table that resolves to the logical blocks on your hard drive that make up the file. That table is essentially a database containing the necessary metadata to link a given file name that you might recognize to the actual location of the files on the physical media that the hardware will recognize.
That may seem like a simplistic place to start when talking about such a complex topic, but that same model plays out no matter what level of storage virtualization you may be talking about. It's just an issue of scope and complexity.
That may seem like a simplistic place to start when talking about such a complex topic, but that same model plays out no matter what level of storage virtualization you may be talking about. It's just an issue of scope and complexity.