PNNL-13501 - Pacific Northwest National Laboratory

• securely moves files to a target resource and submits
job
• provides reporting on progress of job and allows jobs
to be terminated
• monitors the running job, parsing text output files and
returns data to the client
• makes use of existing infrastructure thus providing
for low-cost deployment.
Distributed Data Management
We developed a set of written requirements for distributed
data management through our interactions with scientists
and engineers in chemistry, atmospheric sciences,
manufacturing, materials, and electronic notebooks.
Alternative technologies for addressing these
requirements were investigated. We focused our efforts
on prototyping solutions with the distributed authoring
and versioning protocol, a proposed internet engineering
task force standard. We installed an Apache web server
with a plug-in module for providing back end data and
meta-data storage and performed load and stress testing.
Our research included the development of a three-layer
client application programmer interface. This layering
technique provides clean separation of the protocol
implementation, a data storage abstraction, and an object
abstraction. We also developed the concept of the virtual
document as a key abstraction for dealing with complex
concepts such as calculations or workflows.
Resource Information Services
The primary function of a resource information service is
to provide yellow- and white-page access to information
about system- and user-defined resources. The
incorporation of a resource information service into the
computing infrastructure provides for the use of common
data representations and a shared data source across
projects and organizations.
We researched the use of meta-languages to support the
definition and manipulation of objects in an resource
information service. We settled on the use of the
developing XML Schema standard as the meta-language
and adopted and extended the Directory Services Markup
Language, another developing standard, as a dialect.
Using this dialect, we defined resource information
objects based on previous investigations and our
continuing work with the Gridforum Grid Information
Services working group. We developed software to
generate Netscape Directory Server schema and a Java
binding for accessing and manipulating the objects from
the XML-based object definitions. The use of a metalanguage
and automatic code generation provides an easyto-use
application programmer interface for collaborative
problem-solving environments developers, an easy way to
modify and extend the object definitions, and an
abstraction that allows for the replacement of the
underlying service without affecting the applications that
rely on the service. Significant effort was invested to
develop a layered application programmer interface that
hides the implementation details of the underlying service
and communications protocol.
Atmospheric Sciences Prototype
We worked closely with Laboratory atmospheric science
researchers in many analysis and design sessions. The
purpose of the collaboration was to gather user
requirements for a collaborative problem-solving
environment for regional climate change modeling and to
develop a conceptual prototype. The resulting prototype
provides an overall experimental process representation or
workflow for doing atmospheric research and coupling
impact assessment models for researchers and policy
planners. The prototype is being used to drive an
understanding of the requirements for developing a new
software suite for atmospheric sciences.
Summary and Conclusions
The application of web-based technologies to problemsolving
environments allows the scientific community to
benefit from the robust growth of low-cost commercial
and open-source technologies. We successfully applied
these technologies in the development of multiple
components. We found the performance of http to be
viable for expected use patterns and the prospects for
sufficient scalability to be within reach for many
applications.
We concluded that discovering key abstractions is very
important to component-based architectures for two
reasons:
1. it insulates the client program from changes to the
underlying technology
2. it enables the insertion of a middle layer that can
provide service mappings or translations thus
enabling interoperability.
Additional research is required in this area.
Computational Science and Engineering 107