Information loss
When a document in one format is converted to another there is likely to be information loss. For example, suppose anMarkup languages
Markup languages such as XML can, in principle, hold any information and so the process docA → docX → docA' could be designed to avoid information loss. It is now common to convert legacy formats to XML formats because they have greater interoperability and a wider set of available tools. Thus it is possible to convert Word documents to an XML format and reimport them. The XML document should contain identical information to the legacy format. An important condition is that the roundtrip (legacy → XML → legacy') should result in effectively identical documents. Because some document structures allow some flexibility in content order, whitespace, case-sensitivity, etc. it is useful to have a means of canonicalizing the legacy format. The full roundtrip may then be: :legacy → canonicalLegacy → XML → legacy′ → canonicalLegacy′ If canonicalLegacy = canonicalLegacy′ then the roundtrip has been successful.Character encodings
Limitation
An application can claim to round-trip and be dishonest. For example, it may save the original data from docA as a field in docX, so the reverse transformation to docA′ simply extracts that field. While this may be needed for some cases, the idea of a round-trip conversion is to go through another format representation or data structure and back again. Such a strategy means that small changes in a document means that it can not be converted back to the original format.Usage
The term appears to be common, but not reported in dictionaries. A typical usage occurs iSee also
* Lossy data conversion *