Windows Search - Overview

Overview

Windows Search collectively refers to the indexed search on Windows Vista and later versions of Windows (also referred to as Instant Search) as well as Windows Desktop Search, a standalone add-on for Windows 2000, Windows XP and Windows Server 2003 made available as freeware. All incarnations of Windows Search share a common architecture and indexing technology and use a compatible application programming interface (API).

Windows Search is the successor of the Indexing Service, a remnant of the Object File System feature of the Cairo project which never materialized. Windows Search uses a different architecture.

Windows Search builds a full-text index of files on a computer. (An add-in for Windows XP, Windows Server 2003 and Windows Vista allows network shares to be added to the index.) The time required for the initial creation of this index depends on the amount and type of data to be indexed, and can take up to several hours, but this is a one-time event. Once a file’s contents have been added to this index, Windows Search is able to use the index to search results more rapidly than it would take to search through all the files on the computer. Searches are performed not only on file names, but also on the contents of the file (provided a proper handler for the file type is installed) as well as the keywords, comments and all other forms of metadata that Windows Search recognizes. For instance, searching the computer for "The Beatles" returns a list of music files on the computer which have "The Beatles" in their song titles, artists or album names, as well as any e-mails and documents that include the phrase "The Beatles" in their titles or contents.

Windows Search features incremental search search (also known as "search as you type"). It begins searching as soon as characters are entered in the search box, and keeps on refining and filtering the search results as more characters are typed in. This results in finding the required files even before the full search text is entered.

Windows Search supports IFilters, components that enable search programs to scan files for their contents and metadata. Once an appropriate IFilter has been installed for a particular file format, the IFilter is used to extract the text from files which were saved in that format.

Windows Search by default includes IFilters for common filetypes, including Word documents, Excel spreadsheets, PowerPoint presentations, HTML files, text files, MP3 and WMA music files, WMV, ASF and AVI video files and JPEG, BMP and PNG images.

Windows Search uses property handlers to handle metadata from file formats. A property handler needs a property description and a schema for the property for Windows Search to index the metadata. Protocol handlers are used for indexing specific data stores. For example, files are accessed using File System Protocol Handler, Microsoft Office Outlook data stores using the Outlook Protocol Handler and Internet Explorer cache using the IE History/Cache Protocol Handler.