4.2.1.2 Definition of each AIP
From CLOCKSS Trusted Digital Repository Documents
4.2.1.2 - The repository shall have a definition of each AIP that is adequate for long-term preservation, enabling the identification and parsing of all the required components within that AIP.
[This is necessary in order to explicitly show that the AIPs are fit for their intended purpose, that each component of an AIP has been adequately conceived and executed and the plans for the maintenance of each AIP are in place. (See 4.3, Preservation Planning.)]
The CLOCKSS archive has a single class of AIP, called an Archival Unit (AU), documented in Definition of AIP. Part of that documentation describes the Reference information that forms part of the Preservation Description Information (PDI) of an AIP (AU):
All operations on an AU (AIP) and its constituent components are performed by the AU's plugin, the appropriate instance of its Java class created by supplying its constructor with its parameters. The process of maintaining this plugin definition is documented in LOCKSS: Software Development Process.
- Context: the context information for an AU consists of:
- The plugin ID, which is the encoded name of a Java class implementing the LOCKSS plugin interface.
- The parameters, which are a set of {name, value} pairs providing the arguments needed to construct an instance of the class named by the plugin ID.
- In effect, the context for the AU is a customized instance of a Java class, normally referred to as its plugin. It is thus executable, capable of performing operations on the AU such as adding content and metadata from a SIP (see below), extracting metadata, and taking part in integrity checks.