Jan K. Labanowski: Computational Portals for Chemistry  


Hierarchical contexts defined interaction with the user and available options. User context defines what you are allowed to do. Problem context represents science which you want to do (approach, methodology, object of calculations). Problem does not have any results associated with it and constitutes a high level description of type of computations which need to be performed. The lowest context, application, represents the elementary step in the actual computational run. For multi-step calculations, several applications (software packages) will run in succession. Thus application context defines what software is being run and what comes in and gets out. Session represents a particular run. There may only be a single application within a session, and a single set of input and output files/scripts. But session may also involve a series of consecutive application. In this case, for applications 2...n-1, input comes from a previous application in a chain, and output is consumed by the next application in the chain. Of course, the corresponding output(k-1)-->input(k) pairs have to have not only compatible information but also format. For this reason format converting filter applications may be needed to join applications in the chain.