Technical or administrative metadata is one of the types of metadata and is commonly useful for identification, presentation, and preservation of a resource. In includes information that will be needed to manage the resource over time. Technical information includes some data that can be harvested automatically from many file types such as resolution of an image, recording speed of an audio file, file size, and file format. It also includes information about when, who, and how: what hardware and software was used to produce the digital surrogates of a resource, when the metadata was created, how the item was migrated or edited over time, and who created the surrogates, metadata, or transcripts. And it may include identifiers such as local file names, old URLs for the resource, and current persistent or unique identifiers.
Islandora creates most of the technical metadata for an item during import and stores it in separate data streams. However, some of this technical metadata is contained or duplicated in MODS records. Technical metadata is sometimes duplicated in descriptive metadata because it may be more useful for end users in those locations. Examples of this situation are extent and format information. Technical metadata may also be included in descriptive metadata files due to legacy data. Some platforms, like CONTENTdm, include technical metadata in descriptive metadata files, so information about record creation or hardware used during digitization may be included in descriptive metadata simply because it was mapped over when the objects were migrated from CONTENTdm. Some information that would be more correctly grouped with technical metadata is included in descriptive metadata instead because the Islandora metadata filetypes do not support those data elements. And finally, some technical or administrative metadata (such as identifiers, former URLs, or collection names) are included in descriptive metadata files to support the intellectual control of objects or allow the information to be easily edited or harvested.
To support these use cases, some technical metadata should be recorded in the Excel files for each collection and in the MODS files for each object, even in Islandora. The primary categories are identifiers, location/ownership information, record creation information, and digitization information. Location/ownership information will be split into three additional categories: Physical/original items, Digital Surrogates, and Rights and Usage.