The NCI Drug Information System. 6. System maintenance.

The NCI Drug Information System (DIS) is a collection of 24 interactively searchable databases which contain all the data associated with NCI's drug screening program. Data flow into all of these databases upon a daily basis, and maintenance procedures have been developed which provide a high degree of currency to the files. An extensive security system controls both write access and read access to the DIS and matches both to the authorization possessed by each specific user. Detailed usage statistics are collected automatically. The cost of the overall system in terms of both manpower and machine time is discussed briefly.