Windows Search is an indexing desktop search platform released by Microsoft for the Windows operating system. It is available as part of Windows Vista and Windows Server 2008 operating system, where it is known by the name of Windows Search (also referred to as Instant Search).
For Windows XP and Windows Server 2003, the indexed search technologies are available as Windows Desktop Search (or WDS). While older versions of WDS were available for Windows 2000 as well, the latest release (version 3) is available only for Windows XP and Windows Server 2003.
Windows Search is the indexed search platform that debuted with Windows Vista and offers a superset of the features provided by WDS. However, both Windows Search and WDS share a common architecture and indexing technology, and also are API-compatible with one another. All Ifilters and protocol handlers that work with WDS 3.x will also work with Windows Vista and Windows Server 2008 because of this shared indexing engine.
Ifilters and protocol handlers are what the indexing engine uses to index files and other data stores like e-mail, etc. Windows ships with a number of default IFilters and protocol handlers and supports indexing for over 200 common file types out of the box. To support thumbnails and full previews in the Explorer, a developer would want to write both a thumbnail extractor and a preview handler. To support metadata write-back to a file format on Windows Vista, a developer would want to use a property handler. Going with a simple IFilter is the easiest path, but these other technologies ultimately offer a better user experience.
Windows Search supports
word-wheeling as well as
Advanced Query Syntax. However, unlike WDS, Windows Search can
seamlessly mix indexed and non-indexed files. If the location being searched is
indexed, the search is performed against the index. If it is
not indexed, the files are processed on-the-fly with the same IFilters and Property-handlers as they would be if they were indexed. This allows for more consistent results, though, at the cost of searching speed.
In
indexed locations, both filenames and contents are being searched. However, in
non-indexed locations, only filenames are searched for.
Enterprises will be pleased that Windows Vista has the ability to index files that are taken “offline” or cached locally, but there's more to come with Windows Server 2008... Windows Search in Windows Server 2008 also includes a feature known as Federated Search. Using this, if the file server - on which a network file share is hosted - is running either Windows Vista or Windows Server 2008, any searches against the share will be federated (read: delegated) to the server. The server will perform the search against its local index and present the results to the client system, filtering out the files the user does not have access to. This procedure is totally transparent to the user.
Natural language search is also supported and so the user can search for things like "photo taken last week" or "email sent from Dave". However, this is disabled by default. Natural language search uses expressions in the queries in Natural Query Syntax (NQS), which is the natural language equivalent of AQS.
While Windows 2000 and Windows Server 2003 included the Indexing Service, WDS and Windows Search use a different architecture and a new indexing engine. Windows Search replaces the Indexing Service in Windows Vista and Windows Server 2008 and is available in the Windows Server 2008 "File Server" server role services.
Windows Search Service is a new indexing solution that is included in Windows Server 2008 as a role service in the File Services role. It creates an index of the most common file and non-file data types on your server - such as e-mail, contacts, calendar appointments, documents, photos, multimedia, and other formats extended by non-Microsoft files. Indexing files and data types enables you to perform fast file searches on your server from computers running Windows Vista, or from computers running Windows XP or Windows Server 2003 with Windows Desktop Search installed.
Indexing Service is an indexing solution that is included with Windows Server 2008 and was part of previous releases of Windows.
When you install Windows Search Service using the "Add Roles Wizard" or the "Add Role Services Wizard" in Server Manager, you are given the option to select the volumes that you want to index. We recommend that you select a volume that is used exclusively for hosting shared folders. Indexing files and data types in folders that are not shared on your network will not benefit client computers connecting to your server and will consume system resources.
If you want to index individual shared folders, you can add them later to the list of indexing locations by using Indexing Options in Control Panel.
The Windows Search engine also integrates with Group Policy and allows centralized configuration of the indexer.
The Windows Search indexer runs as a service, known as Windows Search, and performs the I/O operations with low priority. As a result, whenever other processes require the I/O bandwidth or processor time, it is able to pre-empt the indexer, thereby significantly reducing the performance hit associated with the indexer running in the background.
Windows Search technologies share a common architecture and seamless integration with a growing range of Microsoft enterprise search products including Microsoft Office 2007, Microsoft Office SharePoint Server 2007 and Windows Server 2008.
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