Abstract: A Grid management service for deploying legacy code applications on the Grid, without modification of the legacy code, the service having a three layer architecture that is adapted to sit on existing standardised Grid architectures, comprising a front end layer for permitting selection of a desired legacy code application, and for creating a legacy code instance in response to the selection; a resource layer, for defining a legacy code job environment; and a back end layer, for submitting a job for said desired legacy code application, together with information relating to said job environment, for submission to a job manager that arranges for said job to be executed on Grid resources.