You must have encountered that whenever you insert Pendrive or CD in your CD ROM an Autoplay POP up comes.This is the feature of windows that depending on type of contents it provides a list of options saying what do you want windows to do.

DSN stands for Data Source Name.DSN is used for making a connection to a number of databases(Sql,mysql,Access,excel,Dbase,foxpro what not) using ODBC Driver

There are various types of DSN

These DSN differs in terms of
Where DSN info is being stored?
Who can Access that Particular DSN?

File DSN
Access- Any user who has access to the File System. Storing Way-DSN information is stored In a text file with .DSN extension.
System DSN
Access- Any user on that system.
Storing Way- DSN information is stored in Local Machine Section of System Registry.
User DSN