1. A storage device comprising: an interface configured to receive a content search request; a first memory block configured to store files and inverted files corresponding to contents included in the files; a second memory block configured to store a file search table; and a controller configured to control operations of the interface, the first memory block, and the second memory block, wherein the controller creates the inverted file for each content included in the files, and stores IDs of the files including the content in the inverted file, obtains, by search of the content, a corresponding inverted file from the inverted files stored in the first memory block, stores, in the file search table, the IDs of the files included in the obtained inverted file, and outputs the IDs of the files stored in the file search table from the interface as a search result for the content search request.