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 FilesAs 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: BagIt-Version: 0.97 Tag-File-Character-Encoding: UTF-8 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. aptrust-info.txtThis 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”] Note on Bag SerializationBags serialize for use by APTrust must use TAR as their serialization format, MUST not use compression and MUST follow the file and folder naming restrictions as well as end with the .tar extension. Note on Bag SizeInitially bags sent to APTrust should be limited to 250 GB for the final tarred bag. Space available for temporary file processing puts a practical limit on total bag sizes in APTurst. We expect this limit to grow over time but the initial performance data will help determine the final limits for the service. |