Steps towards a virtual solar observatory

We present three categories of sites from which solar data can be retrieved. We describe the retrieval software systems associated with these sites and then present software systems used for analyzing solar data. We show that both retrieval and analysis systems provide only limited global organization and/or standard access of data. We thus also discuss extensions to these systems, including data combination (or mapping) software, reusable software components, and visualization software. We argue that such extensions could eventually provide die level of software support expected by users.