"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."The Library of Congress has been adding to its digital collections for years. Over time, LOC has refined its digital preservation standards.