The Library of Congress has released a digital video, Bagit: Transferring Content for Digital Preservation.
Here's the description:
The Library of Congress's steadily growing digital collections arrive primarily over the network rather than on hardware media. But that data transfer can be difficult because different organizations have different policies and technologies.
The Library—with the California Digital Library and Stanford University – has developed guidelines for creating and moving standardized digital containers, called "bags." A bag functions like a physical envelope that is used to send content through the mail but with bags, a user sends content from one computer to another.
Bags have a sparse, uncomplicated structure that transcends differences in institutional data, data architecture, formats and practices. A bag's minimal but essential metadata is machine readable, which makes it easy to automate ingest of the data. Bags can be sent over computer networks or physically moved using portable storage devices.
Bags have built-in inventory checking, to help ensure that content transferred intact. Bags are flexible and can work in many different settings, including situations where the content is located in more than one place. This video describes the preparation and transfer of data over the network in bags.