Software and hardware requirements of SharePoint 2010:
SharePoint farm is a set of servers that have different roles and offer various services that together make up a server farm suitable for hosting a full SharePoint deployment.
Front-end web servers
These servers publish websites, often called web applications.
These servers host back-end services, such as the search index service, the crawler service, and so forth.
These servers store configuration and content data for the entire SharePoint farm.
Single tier deployment
One server performing all roles.
For the sake of scalability and business continuity, you should deploy a minimum
of two front-end web servers and a back-end database server.
Three-tier farm deployment
It has dedicated application servers.
SQL Server Databases:
SharePoint_ Config_<UniqueId> : Main and fundamental farm configuration database
Content Database: A Content Database is a database file that stores content for one or more Site Collections.