GEMLCA was developed by the research team of Centre for Parallel Computing at the University of Westminster within the UK e-Science OGSA TestBed project. GEMLCA or Grid Execution Management for Legacy Code Architecture is a language independent solution used to deploy existing legacy code applications as a Grid service. Any application written in any language can be deployed as a grid service without the need of even legacy code i.e. binary codes and source code.
It is a computing system consisting of PC clusters. Legacy applications are deployed on these servers as grid services. Compute servers are then accessed by various grid clients for required resources.
Grid host environment is used to implement service oriented grid layer which is based on Open Grid Services Architecture (OGSA) specifications e.g. GT3, GT4, g-Lite or the OMII middleware. This layer is required to connect compute server to OSGA built grid. The selected grid should allow the grid clients to access legacy applications available in compute server like a grid or web services. Administrators should be able to deploy new legacy applications on compute server using different job managers like Condor, Fork, PBS, etc.
GEMLCA resources are consists of legacy codes which are deployed as grid services. These resources are installed on compute server. GEMLCA Resource layer manages the interaction between Grid services and Grid Host Environment. Resource Layer is used for following purposes:
Deploying legacy applications as Grid services
Querying the GEMLCA resources and get the list of available legacy applications
getting the list of legacy parameters with default values and allow the user to modify these
submitting legacy jobs to a job manager
querying the status of previously submitted legacy jobs
retrieving results from legacy applications
GEMLCA Resource layer have following three services:
It deploy a legacy application as a Grid service
It searches for legacy applications available over grid
It manages the workflow processes over Grid such as submiting a legacy application using GEMLCA and getting job status and results back
GEMLCA Clients are installed on client machines which can access resources from compute server. There are two types of GEMLCA clients:
Command line interface
Installation and usage of command line interface is difficult and requires IT skills.
Graphical interfaces provides user friendly environment for grid clients to access grid resources. These are easy to configure and use. Grid portals are used as graphical interface for accessing grid