Execution Management: Key Concepts

Overview

The Globus Toolkit provides both a suite of web services and a "pre-web services" Unix server suite to submit, monitor, and cancel jobs on Grid computing resources. Both systems are known under the moniker "GRAM", while "GRAM4" refers only to the web service implementation. Jobs are computational tasks that may perform input/output operations while running which affect the state of the computational resource and its associated file systems. In practice, such jobs may require coordinated staging of data into the resource prior to job execution and out of the resource following execution. Some users, particularly interactive ones, benefit from accessing output data files as the job is running. Monitoring consists of querying and subscribing for status information such as job state changes.

Grid computing resources are typically operated under the control of a scheduler which implements allocation and prioritization policies while optimizing the execution of all submitted jobs for efficiency and performance. GRAM is not a resource scheduler, but rather a protocol engine for communicating with a range of different local resource schedulers using a standard message format.

For more detailed information about the concepts behind the software implementation, see GT 4.1.3 GRAM4 Approach.