BagIt is a specification for packaging/storing content for preservation and transfer. For Chronopolis, we use the bagit specification as a base, only updating certain files to be required.
Currently we require sha256 for Chronopolis, so all manifests are appended with "-sha256"
The data files (the payload of a bag) in the BagIt spec are all the files found under the data directory. If there are orphaned files (those not found in the manifest, but exist in the data directory), a bag is deemed to be invalid.
Tag files are all those in that exist outside of the data directory. The bagit.txt and bag-info.txt files are standard and we follow the same requirements as in the BagIt specification for them.
- Required as part of the bagit spec
- Contains the digest of a file with the relative path from the bags root directory
- Uses the same output as the md5sum/sha256sum command line utilities
- We require the existence of a tagmanifest, which contains the digest of each tag file and the manifest.
- This lets us validate not only the tag files but also the manifest we were given.
- When doing bagging ourselves, we create this only if each file in the manifest has been validated
- Required for UCSD deposits.
Information listed should come from the UCSD depositor SLA.
bag command will add
Optional Tag Files
Each optional file is digested and added to the tagmanifest. Validation on optional files is not currently supported.
Unaccepted Tag Files
- fetch.txt files are not accepted into Chronopolis (although legacy examples may exist)