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grids and service grids, but the basic architecture of such a computing
paradigm has not changed much. In 2001, the i ve-layer sand-glass
architecture was proposed and generally accepted. With the application
and standardization of grid computing, the architecture and its support-
ing technology became an important research issue. OGSA is a service-
oriented architecture, which adopts the service as a unii ed resource
encapsulation format to provide better extensibility and interoperability
between grid resources. WSRF rei nes the service interface and interop-
erating protocols of OGSA, and makes OGSA a Web service-compatible
implementation framework, which helps the merging of grid and Web
service technology proceed more smoothly.
In fact, the i ve -layer sa nd- gla ss a rc h ite c t u re si mply propo s ed a n abst rac t
functionality structure for the service grid. OGSA/WSRF provided an
implementation framework based on the service concept and a set of grid
service interfaces, neither of which discussed the design principles, middle-
ware component dei nitions, and the detailed solutions for access control
and trust management in the service grid. In this chapter, we analyze the
requirements of typical grid applications, and provide a detailed introduc-
tion of CROWN middleware and its architecture, design principles, and
kernel technologies based on OGSA/WSRF service grid architecture.
Generally, there are three kinds of services in an OGSA/WSRF service
grid: general services, resource encapsulating services, and application-
specii c services. General services, such as the grid job broker service,
metascheduling service, and grid information services (GISs), are an
important part of a service grid middleware. In a typical application grid
scenario (see Figure 1.1), a user i rst submits a job to the metascheduling
service, and then gets the job status and result from the job broker service;
the metascheduling service retrieves the resource requirements from the
Service index center
Information
exchange
Grid information
service
Grid information
service
Service discovery
Service registration &
resource update
Service requestor
Service provider
Job submission
Meta schedule
service
User proxy
Resource
monitor
Resource encapsula-
tion service
Create/manage
Grid resource
Grid job proxy
Query job status &
get job result
Asynchronous notification
Service access
FIGURE 1.1
CROWN-based service grid application pattern.
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