The data model of the CACTVS program suite (Chemical Algorithms Construction, Threading, and Verification System) is presented. CACTVS is an open environment which readily integrates new computational modules and data format descriptions in the domain of computational chemistry. These chemical information (property) computation modules are provided with requested input data, typically transparently computed by other modules. Computational results are managed appropriately with regard to file and data base I/O, transport to display servers, input for high-level routines, and report generation. Definitions of property characteristics which include optionally precompiled objects and source plus additional documentation may be stored in networked data bases for global access; This facilitates module reusal and the exchange of modules between interested parties. The elementary data format handling routines and the property computation routines need not to be part of the core program. They are retrieved from and loaded dynamically at run time from local files or data bases which can be reached on the network. This look-up process can be made completely transparent, resulting in a comparably small core program which grows only on demand to incorporate procedures for the evaluation of requested information. A model for asynchronous distributed client-server computations is supported as an alternative to dynamic linking for expensive calculations. CACTVS is intended to make algorithm development in chemistry more productive and to help in collecting the synergetic benefits from the concerted application of compatible algorithm sets which derive chemical information in all its variety.
