Just the language in the new Globus-IBM paper, "The Physiology of the Grid,"
suggests an evolution in computing environments.
Until now, application developers could count on target environments to
be "homogenous, reliable, secure and centrally managed," the paper
said.
Increasingly, however, computing is becoming concerned with
"collaboration, data sharing and other new modes of interaction that
involve distributed resources," the paper said. "The result is an
increased focus on the interconnection of systems both within and across
enterprises, whether in the form of intelligent networks, switching
devices, caching services, appliance servers, storage systems, or
storage area network management systems." Outsourcing also contributes
to a more decentralized environment.
"These evolutionary pressures generate new requirements for distributed
application development and deployment," the paper said.
The paper - authored by Ian Foster and Steven Tuecke of Argonne National
Laboratory and Carl Kesselman of the University of Southern California,
collaborators on the widely adopted Globus Toolkit, and Jeffrey Nick of
IBM - follows up on the first Globus paper, The Anatomy of the Grid.
(The new paper is available here.)
Paper To Be Discussed At Global Grid Forum; Globus Toolkit 3.0
Planned
Foster said the paper is "a natural evolution of our ongoing work aimed
at defining and gaining broad acceptance for standard open Grid
protocols, and providing the best possible open source, open
architecture implementation of those protocols, in the form of the
Globus Toolkit."
At Global Grid Forum 4 in Toronto two weeks from now, "we will propose
the creation of a working group aimed at further refining the draft
technical specifications that we have developed for OGSA [The Open Grid
Services Architecture described in the new paper], and creating
additional complementary specifications. Concurrently, we have already
started prototyping activities aimed at creating an OGSA-compliant
Globus Toolkit 3.0," he said.
New Paper Focuses On Services
The first Globus paper focused on the protocols required for
interoperability among virtual organization (VO) components. The focus
of the new paper is on the nature of the services that respond to
protocol messages.
"We view a Grid as an extensible set of Grid services that may be
aggregated in various ways to meet the needs of VOs, which themselves
can be defined in part by the services that they operate and share," the
authors wrote. "We then define the behaviors that such Grid services
should possess in order to support distributed systems integration. By
stressing functionality (i.e., 'physiology'), this view of Grids
complements the previous protocol-oriented ('anatomical')
description."
The paper also discusses how Grid technologies can be aligned with Web
services technologies, such as service description and discovery;
automatic generation of client and server code from services
descriptions; binding of service descriptions to interoperable network
protocols; compatibility with emerging higher-level open standards,
services and tools; and broad commercial support.
"We call this alignment - and augmentation - of Grid and Web services
technologies an Open Grid Services Architecture (OGSA), with the term
architecture denoting here a well-defined set of basic interfaces from
which can be constructed interesting systems, and open being used to
communicate extensibility, vendor neutrality, and commitment to a
community standardization process," the paper said. The architecture
uses the Web Services Description Language (WSDL) to achieve
self-describing, discoverable services and interoperable protocols, with
extensions to support multiple coordinated interfaces and change
management.
The paper is focused on commercial applications because of their greater
need for seamless integration with existing resources and applications
and with tools for workload, resource, security, network QoS, and
availability management.
"As today's enterprise systems are transformed from separate computing
resource islands to integrated, multitiered distributed systems, service
components can be integrated dynamically and flexibly, both within and
across various organizational boundaries," the authors wrote.
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