SDSC and UCSB have worked out an agreement to co-develop, test, and mechanisms for ADL to store large quantities of data (mostly images) in SDSC's Massive Data Analysis System (MDAS), using services of the the MDAS Storage Resource Broker (SRB). SRB is a set of client/server-type tools that provide uniform access to diverse, distributed data sources such as Unix file systems, HPSS, and RDBMSs such as Oracle.
Specific action items in this agreement include:
1. Developing and testing an ADL Object Id (ADL_OI) system such that ADL can access ADL objects stored in SRB via the ADL_OI key. Since files in ADL are referenced by a URL, a first task is to ``invent'' a new type of URL that names files in the SRB system. This is largely a matter of agreeing on a syntax. SDSC will handle the problem of taking such URLs and converting them into the appropriate SRB retrieval commands.
2. Installing and testing the existing MDAS SRB Client Interface on a local (ADL) machine to support remote ADL image storage at SDSC. ADL has recently received the client software from SDSC.
3. Generating thumbnails and browse graphics at SDSC, with the use of SDSC supercomputer time to generate thumbnails and browse graphics for some of our larger data sets, such as the USGS DOQ collection. At the moment, the major limiting factor in processing the DOQ collection has been tape drive speed, not CPU time.
4. Porting the current ADL testbed system (GIJI) to SDSC, since SDSC is still running the old version of ADL.
5. Exploring uniform ways of querying external databases and developing an SRB search interface. External database are defined as databases for which neither ADL nor MDAS have direct information about the schema. A possible way to provide uniform query access to external databases is for each external database to provide a standard schema description interface. ADL has done some work in this area. In the previous ADL testbed, a schema definition system is used to provide a uniform query system for two radically different underlying databases, namely the catalog and the gazetteer. The SRB system maintains metadata on contents and has a search capability. From the perspective of ADL, this means that it may be possible for ADL to treat the SRB system as a remote geospatial collection that can be searched just like the ADL catalog. From the perspective of SRB, this means that ADL can possibly act as an alternate, domain-specific search engine for the SRB system. There are many details to work concerning this issue.