Bag StructureBags must have the following structure. Items in bold are required. Others are optional. Additional notes appear below. Note the new rules on manifests! <institution_id.item_uid[.b###.of###]>/ | aptrust-info.txt | bag-info.txt | bagit.txt | manifest-md5.txt and/or manifest-sha256.txt | tagmanifest-md5.txt | tagmanifest-sha256.txt | [custom tag files] \----data/ | [payload files] \----[custom_tag_dir]/ | [custom tag files] \----[custom_tag_dir]/ | [custom tag files] ManifestsBefore March 29, 2016, APTrust accepted and verified only the manifest-md5.txt file. We will now accept either manifest-md5.txt or manifest-sha256.txt. If you supply both, we will validate both. Tag ManifestsWe will validate all tag manifests, though they are optional. We will accept tag files not listed in the tag manifests, though obviously we cannot validate their checksums. Custom Tag Files As of March 29, 2016, we preserve all tag files, except bagit.txt, which will be recreated when you restore a bag. Custom tag files may be in any format, including binary. We will not try to parse them, but we will validate their checksums if they are listed in the tag manifests. Required Tag Filesbagit.txtThis is requited by the BagIt specification, and should contain the following: Manifest fileA bag manifest file MUST be in every bag to confirm the fixity of files in the data directory. APTrust bags should use the MD5 checksum algorithm for file fixity in it’s manifest. Note that this fixity is only used to confirm integrity of transfer, for preservation a cryptographically secure fixity will be generated. Following the convention of the BagIt specification, manifest files must be named ‘manifest-md5.txt’. Bags MAY contain other manifest files (i.e. if we’re accepting bags generated at a partner institution) but these will be ignored by APTrust processing scripts. bag-info.txt fileValid APTrust bags MUST contain a bag-info.txt file with the following fields, which may be blank: Source-Organization: This should be the human readable name of the APTrust partner organization. Bagging-Date: as per specification using ISO 8601 UTC format. Bag-Count: as per specification Internal-Sender-Description: [Optional] Human readable description of the contents of the bag. Internal-Sender-Identifier: [Optional] Internal or alternate identifier used at the senders location. This file MAY contain additional fields for the same reasons stated in “Other Files” below, but they will be ignored as part of APTrust. See specification for more information. aptrust-info.txtAdditional tag metadata for aptrust will be kept in this tag file, optional in the BagIt specification this allows bags to be used for multiple purposes without fear of collision. (For instance in DPN. This file MUST be present and MUST contain the following tag fields. Title: Human readable title for searching and listing in APTrust. Access: One of three enumerated access conditions. [“Consortia”, “Restricted”, “Institution”] Other Files |