System Databases in SQL Server

SQL server installation create some system databases automatically, you can see these database in your SQL server management studio:

DatabaseDescriptionDatabase file nameLog file name
masterContains all system level information for a SQL Server system. It records information about all login accounts and all system configuration settings.Master.mdfMastlog.ldf
modelThe template for all databases that are created on the instance of SQL Server.model.mdfModellog.ldf
msdbThis database used by the SQL Server Agent for configuring alerts and scheduled jobs etcMsdbdata.mdfMsdblog.ldf
tempdbContains all temporary tables, temporary stored procedures, and any other temporary storage.tempdb database is re-created every time SQL Server is started so the system starts with a clean copy of the database.Tempdb.mdfTemplog.ldf