Hi, I have an action to provide general descriptions for half of the computing entities, and this is my attempt. I think we also need better descriptions for many of the attributes, but I'd rather do that by editing the file. I'm not sure if we should say anything about how GLUE 1 concepts map to GLUE 2, but it may be helpful. ExecutionEnvironment The ExecutionEnvironment class describes the hardware and operating system environment in which a job will run. It represents a set of homogeneous Worker Nodes, so if a computing system contains nodes with significantly different properties there may be several ExecutionEnvironment instances. (This is similar to the GlueSubCluster object in GLUE 1.) This implies that it should be possible to request a specific environment when a job is submitted. The ExecutionEnvironment may refer to virtual rather than physical machines. As well as attributes describing a typical node, the class gives summary information about the size and usage of the set of nodes which posess those properties. However, there is no way to relate these to the information in other entities, e.g. it is not possible to know which jobs in a given ComputingShare are running on which ExecutionEnvironment. ApplicationEnvironment The ApplicationEnvironment class describes the software environment in which a job will run, i.e. what pre-installed software will be available to it. Each Application is identified by a name (the AppName attribute); these names are not defined within the schema, but SHOULD be assigned in a way which allows applications to be uniquely identifed. The properties of installed software may vary substantially, but the attributes of the class cover the most common cases, in particular for licensed software. If necessary, additional information can be added using the OtherInfo attribute and the Extension class. ApplicationHandle The ApplicationHandle class is an extension to ApplicationEnvironment for applications which need to be set up in some way before they can be used. For each supported setup method a string can be specified, the interpretation of which is specific to the method - in the simplest case this could just be a setup script to execute. ComputingActivity The ComputingActivity class represents a single (but possibly multi-processor) job. The attributes give the job properties and state as seen by the local batch system, together with some Grid-level information. ToStorageService The ToStorageService class represents the case where a filesystem from a Storage Service is available to jobs running on a Computing Service via posix access, e.g. as an NFS mount. Each ToTorageService instance represents a single mount point. It is assumed that such mounts are available on all nodes (i.e. all Execution Environments) in the Computing Service. Stephen -- Scanned by iCritical.