Tinnitus is the name for these head noises, and they are very common. Nearly 36 million other Americans suffer from this discomfort. Tinnitus may come and go, or you may be aware of a continuous sound. It can vary in pitch from a low roar to a high squeal or whine and you may hear it in one or both ears.
By default, the directory where all database files and transaction log files are located is \Program Files\Microsoft SQL Server\Mssql.1\Mssql\Data. When you run SQL Server Setup, you can specify a different location as the default location for data files. The data file location is the root directory where Setup creates the folders that contain database and log files, in addition to directories for the System log, back-up, and replication data.
Different vendors use these terminologies to mean different things. In Oracle-speak, a database is the collection of datafiles on disk. These datafiles belong to your tablespaces. They are also the online redo log files, the parameter file, the password file, and the control files. A database exists on disk and will be there even if you shut down the server and reboot it. But a database is not accessible by itself. You have to sign on to SQL*Plus and issue a STARTUP command.