Conversion technology, an assessment

T wo factors make conversion necessary: changes in users' functional requirements and changes in their performance requirements. These changes may necessitate the acquisition of new software and hardware which, in turn, may require changes to the existing data programs. For example, the acquisition of a DBMS to replace a file management system requires the integration of the original files into a data base system and modification of the programs to interact with it. The replacement of a current DBMS with a new data base system to provide additional functionality may require a different way of logically struc-turing the information (its data model) and a different kind of language interface. The establishment of a communication network between differing systems to implement data sharing will require dynamic, in real time, conversion of data between different nodes in the sense that the same item will repeatedly undergo conversion as it is needed, or alternatively, it requires conversion of programs when they travel to different nodes to access data there. Even when the acquisition of new software or hardware is not warranted, changes in a users' functional and performance requirements can require data and program conversion. What makes conversion difficult is the proliferation of data models and levels and styles of DBMS interfaces, internal data representation and hardware architecture. When conversion is necessary, users will extract data from their source environment and restructure them to the form required for the target environment. While the extraction and restructuring may themselves be complex, these processes are frequently complicated further by the undisciplined nature of the source data. For example, data may exist in duplicate or contain numerous errors and multiple inconsistencies. The whole process of extracting it from its source, "cleaning the data," restructuring it to a desired form and loading it into the intended environment is generally referred to as data conversion or translation.

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