About the Technology
The Portal to Texas History infrastructure is implemented with open source components and open, standards-based protocols and formats.
We designed the underlying system for the Portal with principals of shared nothing, distributed architectures in mind. By allowing the system to continue operation when one component might not work correctly, we ensure that users are still able to get to our content.
For all public-facing components of the system, we use the Django Web framework. Django is an open source framework written in the Python programming language. We build back-end services with Python and technologies such as mod_python and web.py; these services exist on a closed network which increases throughput and security in the system. Solr is our full-text indexer of choice in the Portal, and most interactions with the system directly or indirectly connect with one of our Solr indexes.
Digital objects are represented in the system with the Metadata Encoding and Transmission Standard (METS) which provides a way to describe the structure of complex digital objects. For the descriptive metadata process, we employ a locally qualified version of Dublin Core called UNTL. It is possible for the system to convert this format on the fly to simple Dublin Core and MODS. In the future we hope to support additional machine-readable metadata formats.
The files and metadata that comprise digital objects are distributed to several static and metadata server nodes and written to disk using the Pairtree specification. We implement persistent linking and other services in the system with the Archival Resource Key (ARK) specification.