Most "real" databases don't run on "files", they use their own FS and span entire disks. You probably won't be able to copy over a file, you need to unload the database to a set of files and then move ...

We have an ancient AS/400 730 system that still houses some old budget/financial data. We'd like to decommission this box, and migrate the data to a SQL server. The data won't be modified or changed ...