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Data corruption refers to errors in computer data that occur during writing, reading, storage, transmission, or processing, which introduce unintended changes to the original data. Computer, transmission and storage systems use a number of measures to provide end-to-end data integrity, or lack of errors. In general, when data corruption occurs, a file containing that data will produce unexpected results when accessed by the system or the related application; results could range from a minor loss of data to a system crash. For example, if a Microsoft Word file is corrupted, when a person tries to open that file with MS Word, they may get an error message, thus the file would not be opened or the file might open with some of the data corrupted. The image to the right is a corrupted jpg file in which most of the information has been lost. Some programs can give a suggestion to repair the file automatically (after the error), and some programs cannot repair it. It depends on the level of corruption, and the built-in functionality of the application to handle the error. There are various causes of the corruption. == Overview == There are two types of data corruption associated with computer systems: ; Undetected : Also known as ''silent data corruption;'' such problems are the most dangerous errors as there is no indication that the data is incorrect. ; Detected : Detected errors may be permanent with the loss of data or maybe temporary where some part of the system is able to detect and correct the error, in this latter case there is no data corruption. Data corruption can occur at any level in a system, from the host to the storage medium. Modern systems attempt to detect corruption at many layers and then recover or correct the corruption; this is almost always successful but very rarely the information arriving in the systems memory is corrupted and can cause unpredictable results. Data corruption during transmission has a variety of causes. Interruption of data transmission causes information loss. Environmental conditions can interfere with data transmission, especially when dealing with wireless transmission methods. Heavy clouds can block satellite transmissions. Wireless networks are susceptible to interference from devices such as microwave ovens. Hardware and software failure are the two main causes for data loss. Background radiation, head crashes, and aging or wear of the storage device fall into the former category, while software failure typically occurs due to bugs in the code. Cosmic rays cause most soft errors in DRAM. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Data corruption」の詳細全文を読む スポンサード リンク
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