Gridbus Workflow Enactment Engine - Grid Computing: Infrastructure, Service, and Applications - page 123

WCO Event service TM1 Resources TM2 TM3

Register task status events

Activate

Send status [executing]

Notify status [executing]

Activate

Activate

Register output event [Parent taskName, portNo]

Register output event [parent taskName, portNo]

Submit job

Inform output location

Wait for inputs

Wait for inputs

Notify output to registered TM

Notify output to registered TM

Send status [done]

Notify status [done]

Send status [executing]
Send status [executing]

Notify status [done]

Submit job

Submit job

FIGURE 5.6 Interaction sequence diagram of the WCO, TMs, and ESS.

and TM3 through ESS, saying “ my output of port No. x is ready and its loca-
tion is xxxx .” If all input data for TM2 and TM3 are ready, TM2 and TM3
report execution status to ESS, and then proceed to initialize the execution
of their tasks. After WCO receives the notii cation of the execution of the
tasks in TM2 and TM3, WCO will activate their child TMs, so that they
can prepare for task execution. This process will be continued until the
end of workl ow execution.

5.4 Service Discovery
In a grid environment, many services with the same functionality and
user interaction can be provided by different organizations. In addition,
a service may be replicated and deployed in many locations. From the