Computer data transfer/ migration is the process of moving data from one storage media to another, typically by using specialized software. Users may require the transfer of their data for a variety of reasons such as changing computer systems, upgrading storage media or merging the contents of multiple storage media. The process of transferring data can generally be separated into three phases, including extraction and loading, validation and verification. The specific tasks performed during a data transfer depend on the type of transfer.

Considerations

It is essential for the data transfer to retain the original file organization. This will allow users to access all of their old data such as documents, music, pictures and movies. A complete data transfer should also keep the original system settings like web browser bookmarks and favorites. This process can become more complex when transferring data between two different operating systems.

Categories

Data transfers can be categorized according to the reason for the transfer and the approach that the analyst selects. A storage migration is the simple transfer of data from one storage medium to another without changing the data. An application migration involves moving the data between application platforms, which typically involves the substantial transformation of data. A database migration moves data from one database to another also requires substantial data modification in most cases. A data migration that is performed due to a change in business process often requires business management tools in addition to data migration software.

Extraction and Loading

The extraction and loading phase requires the data analyst to map the data to the new system. This generally involves relating the old data formats to the formats and other requirements of the new system. The data migration software then reads the data from the old storage media and writes it onto the new storage media.

Validation

The validation phase occurs between the extraction and loading steps. It involves the development of an input file specification that requires the data to meet the analyst’s criteria before it may be transferred. An input file specification is not always necessary, and some data transfers allow the analyst to perform validation on the fly when the data is loaded to the new media. This approach involves the software reporting loading errors as they occur.

An analyst should only consider on-the-fly validation when the extracted data from the old storage media is not tightly integrated with modified data on the new storage media. This type of validation should be used with caution when the data transfer includes system files.

Verification

The verification phase occurs after the loading step. It ensures the data on the new storage media is complete and has been accurately translated onto the new system. Verification must also ensure that the data will support the processes on the new system. This phase may require the new and old systems to be run in parallel to identify any disparate areas between the two systems. The verification phase may also involve modifying the data to eliminate obsolete information or conform the data to new system requirements.