Detected and Undetected Corruption

Data corruption is one of the most common errors that computer users face. Data corruption occurs when code is intentionally or unintentionally changed from its correct form. Corruption can be systematic or random, but a small change can break a program or render a file pretty useless.

Corruption has a variety of causes. Stray particles could change a zero to a one, or vice versa, even when the computer is turned off. If stray particles don’t corrupt data, then you can always count on physical decay; magnetic drives (HDDs) lose their orientation, electrically charged media (flash storage) gradually lose charge and optical media (tapes) breaks down as the plastic gradually degrades. So, then, it is somewhat inevitable that all digital media is destined to be corrupted in the end.

Data corruption can be a very serious problem, especially for systems that are so critical that lives depend on them. For home users, human error is the most common source of media corruption, such as deleting or modifying a file that shouldn’t be. Other common causes include malicious activity, such as malware, or plain old-fashioned media degradation and mechanical failure.

Data corruption can broadly be put into two categories – detected and undetected. The former causes frequent, less severe problems, but the latter may result in a complete system crash. As the description suggests, detected corruption is exactly that. You might, for example, open an image and find that it is now filled with things that shouldn’t be there. While this clearly isn’t good, it might give you the chance to investigate further and get to the bottom of whether the corruption was random, or if it was caused by a problem that is fixable. The plus side of detectable corruption is that it’s usually minor, normally limited in scope and crucially, recoverable. While they may eventually lead to bigger problems, they will give the user a chance to prepare.

Undetected corruption, on the other hand, is a more serious issue. The most serious corruption issues occur when the source is not identified and addressed early on. Corruption is like a disease – found early, and you can put a stop to it. But the longer it’s left, the greater the chance of losing all of your data. For example, you might be using a flawed power supply. If, on occasion, the faulty power source undervaults the power supply, it could create bad sectors. If the error hits a portion of the hard drive with critical data, like drivers or operating system information, your hard drive could be rendered useless. Another example is a tiny particle of dust on the hard disk platter, gradually scratching the surface. The longer this occurs, the higher the chance of no data being recoverable, even by a professional data recovery specialist

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