a .net data provider is a collection of objects used to communicate between a data source and a data set in other words a data provider is used to communicate with a data source i e database execute commands against the data source and then retrieve results from the data source
By default, the work item file attachment size limit is 2,048 kilobytes (2 MB). For information on how to change the attachment size limit, see How to: Set the Maximum Attachment Size for Work Items. Consider the implications carefully before changing the default attachment size limit. Changing the attachment limit value will alter the attachment size limit for all Team Foundation Server users.
This is in order to prevent the message from lying in the Outbox without being sent. For example if your email server allows 30MB attachment sizes, Outlook 2010 will still not allow you to send more than 20MB. But you can always change this setting in Outlook 2010. Although Outlook does not provide an interface to set the maximum size limit, you can easily change this using registry changes.