It seems like the days of hunting and browsing for content in an information system have passed and users want to type keywords into a text box and retrieve information rapidly. For example of how search has revolutionized the way we do business is in the phase out of large network drives in favor of document management systems, like SharePoint.We have replaced large laborious network drives with SharePoint document libraries, tagging, metadata, and advanced search capabilities. Microsoft has redesigned the architecture of SharePoint 2013 search. Unlike previous versions of SharePoint, the search platform is the same across all version types of SharePoint 2013: Foundation, Standard, and Enterprise. SharePoint 2013 search uses a combination of components to create the search platform, and provides pervasive search functionality throughout the product. SharePoint 2013 includes the major components of FAST in the search offering, and installs them by default as part of SharePoint Enterprise Search.

• Search-driven navigation
• Better people and expertise search
• Compliance via eDiscovery
• Easier management for administrators
• Catalog-based search and recommendations for business users
• New improved user interface and experience
• SharePoint Search 2013 Logical  Architecture

SharePoint 2013 search consists of several components in the overarching search architecture. The search  Components associate with each Search Service Application (SSA) in the farm, and administrators may scale the components to multiple application servers to distribute load and provide redundancy. The crawl component is responsible for crawling over multiple content sources, which might vary in type. The following lists most of the content source types available, and you may create multiple content sources of any type to crawl data for SharePoint search results:

• SharePoint content
• SharePoint user profiles
• Web pages via HTTP
• File shares
• Exchange
• Lotus Notes
• Custom sources

The content processing component is responsible for processing items crawled by the crawl component and passing these items to the index component. This component is responsible for parsing document content, property  apping, and leveraging IFILTERs to parse content from Office and third-party document types. The index component serves two purposes: to take items from the content processing component and index them and to satisfy search queries from the query processing component by providing search results. In both cases, the index component utilizes index files, stored on the disk of the application server. Just like in FAST, the structure of indexes is in tabular format, with rows representing index replicas—redundancy in groups of servers—and columns representing index partitions—indexes split across multiple servers. The query processing component handles search query linguistics. Functions of this component include processing of words, stemming, spell check, thesaurus, etc. This component understands Keyword Query Language (KQL) and FAST Query Language (FQL) syntax for complex structured queries. The query processing component feeds processed queries to the index component to produce a set of search results. The search administration component provides the user interface for configuring and managing search settings, of the various components. This component consists of a service application, running within SharePoint, and accessed via Managed Application Settings. The topology assumes multiple application servers, web-front-end (WFE) servers, and databases. In this example, the hosts are physical servers and servers within each host exist as virtual machines. Query Server: its responsible for responding to user search requests Index Server: Also referred as Crawl Server. Excel Service: It’s about supporting excel service in client browser. Usage and Health Data Collection: It enables the collection of all the diagnostic and usage data from your entire SharePoint farm in one database.