Abstract: In a computer system of the multi-task type, when a plurality of tasks execute related data processings, ID data specifically provided for the data processings is generated, and recorded. With the recorded ID, an exclusive control and a shared control in the access to a predetermined resource are performed. When, after a main task records ID data and makes an access to a resource, another task requests the access to the resource on the basis of another ID data, the access to the resource is prohibited or the resource rejects the access to it. When a sub task executing the data processing related to that executed by the main task makes an access to the resource by using the request and the ID data both supplied from the main task, the sub task can access to the resource.

Abstract: In a data management system of this invention, data elements to be registered are managed by item information records each comprising a name of the data element, an item code corresponding to an item to which the data element belongs, and a serial number. The relation between item information records is managed by a relation information record expressed by a source item ID, an object item ID, an item code associated with a source corresponding to an item, and a relation ID indicating the relation between the source and object items. The relation ID is given by a relation table. When a search instruction is input, the item information record, the relation information record, and the relation table are referred to, thus obtaining item information to be searched. The item formation record and relation information record can be registered as needed.