Mirroring the ADS bibliographic databases

During the past year the Astrophysics Data System has set up two mirror sites for the benefit of users around the world with a slow network connection to the main ADS server in Cambridge, MA. In order to clone the ADS abstract and article services on the mirror sites, the structure of the bibliographic databases, query forms and search scripts has been made both site- and platform-independent by creating a set of configuration parameters that define the characteristics of each mirror site and by modifying the database management software to use such parameters. Regular updates to the databases are performed on the main ADS server and then mirrored on the remote sites using a modular set of scripts capable of performing both incremental and full updates. The use of software packages capable of authentication, as well as data compression and encryption, permits secure and fast data transfers over the network, making it possible to run the mirroring procedures in an unsupervised fashion.