1 Background - mountain.PROJECTS

TURKU UNIVERSITY DEPARTMENT OF GEOGRAPHY PUBLICATIONS B Nr 4The Catalog Server is the fix-point in the network. At start-up, each Data Server reports itsnetwork address and some key meta information to the Catalog Server. The Data Serversrepeat this reporting at regular time intervals throughout their lifetime, so the Catalogmaintains an updated image of which Data Servers are available, and what data they currentlypresent. In the project only one Catalog Server is put into operation (at NORUT IT), so allData Servers reports their existence to this central point.The OMEGA Loader is a standalone Windows program responsible for loading data into theData Servers. Through contact with the Catalog Server it obtain a list of the available servers,and can contact any of these through CORBA. The OMEGA Loader uploads OMEGAProducts from the local file domain to the Data Servers. In this process it attach certainmetadata elements to each product in order to facilitate subsequent search and browsingoperations.The OMEGA Browser Facility is responsible for helping the user to locate, view anddownload OMEGA Products, independent of where they are stored. The user interface is webbased, and implemented a Java Server Page solution. Installed on a Web Server at NORUTIT, any user can use the OMEGA Browser from a browser platform (e.g. Internet Explorer).Figure 37. Overall OMEGA System architecture.The OMEGA Browser Java Server Page relies on an OMEGA Web Service (OWS) for itsbusiness logic. The OWS further rely on the OMEGA Store (OS-CGI) Cgi program, but thesetwo might merge in the future. Together these two components hides the details of thedistributed (CORBA) network of Data Servers, and present an http/xml based interface forclients to access the Data Server network.54