In SQL Server, the database can be stored in different files and filegroups. If your database is small (100 MB or less), you do not need to worry too much about files and filegroups.

We use linked servers in SQL Server 2000 (I know...) to pump data from an AS400 running DB2 in to some tables in SQL Server to do analysis. It is realy painful as the source system is a Danish ERP ...