SP maintains logs of the ingest process to ensure that everything that is recieved as part of a Provider's dataset is ingested into the repository. See 4.2.1 - 4.2.4 and 4.1.8.
SP provides mechanisms to ensure that the content held in the repository remains uncorrupted through the use of regular fixity checks. See Fixity Check Procedures.
While SP has a record and can generate a list of everything it has in the repositiry, the repository can only ingest the content that a Provider chooses to send. It is difficult to know whether or not this represents the entirety of the collection without a complete list to check it against. These gaps can be identified through feedback from the Designated Community. Additionally, SP supports and is involved with the Keepers Registry in order to help create a central registry of scholarly journal content.
Digital Preservation Policy Librarian