Architecture

A high level architectural description of JumpStart is illustrated below. The architecture is based on two primary levels: 

• client and 
• Netmark-XDB7 service; 

the figure also shows on a more detailed level internal components and communication between components.

At the heart of JumpStart is a high-throughput information integration and management system, also developed at NASA, called Netmark-XDB [1]. The key design considerations held in the Netmark system design are outlined below: 

• Enabling meaningful government-to-government information sharing using international standards, in order to improve mission safety and success 
• Enabling effective information management systems that utilize indigenous user interfaces (e.g., spreadsheets as user interfaces), in order to improve system usability 
• Enabling rapid development of customized system applications with an enabling platform, in order to reduce time from system concept to system deployment 
• Eliminating the need for database analysts using a ‘schema-less’ design, in order to reduce system maintenance costs 

Netmark supports the XML standard for metadata and information interchange thus making it an open system that is interoperable with a wide variety of other information systems and tools.

Netmark is essentially a data management system for “semistructured” data i.e., data in the above enumerated kinds of business documents (such as reports in Word or PDF, presentations in formats such PowerPoint, Excel spreadsheets etc.) which does not have a formal “schema”, but where there is indeed some structure in the document implicit from the format and layout. Data loaded into Netmark (done by simple drag and drop) is converted into XML and stored in the data store. The data store is an XMLover- relational data management system. Data can be retrieved very conveniently from Netmark using simple Web-based interfaces that require simple keyword-based input. Netmark also provides powerful data aggregation and composition capabilities.

Clients communicate with the XDB service exclusively over the standards-compliant HTTP8 and WebDAV9 protocol extensions. The protocol-specific headers, client authentication, and feature negotiations are managed by the HTTP server framework—currently Apache’s HTTPD10. Information storage, retrieval, and recomposition modules connect to the Apache server and provide their services through handler API’s as defined in the Apache framework.

The XDB DAV module handles WebDAV requests for document storage and retrieval—including decomposition via a pipeline system and storage of decomposed documents in the XDB data store. Information is protected with a fullfeatured access control mechanism to ensure data security. The XDB Query module provides XDB datastore querying capabilities including content and context querying, information recomposition, server-side transformation (using the Xalan11 XSLT12 processor), and information access control enforcement.