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Data degradation is the gradual corruption of computer data due to an accumulation of non-critical failures in a data storage device. It is also referred to as data decay, data rot or bit rot. [1] This results in a decline in data quality over time, even when the data is not being utilized.
Data degradation in dynamic random-access memory (DRAM) can occur when the electric charge of a bit in DRAM disperses, possibly altering program code or stored data. DRAM may be altered by cosmic rays [2] or other high-energy particles. Such data degradation is known as a soft error. [3] ECC memory can be used to mitigate this type of data degradation. [4]
Data degradation results from the gradual decay of storage media over the course of years or longer. Causes vary by medium:
Below are several digital images illustrating data degradation, all consisting of 326,272 bits. The original photo is displayed first. In the next image, a single bit was changed from 0 to 1. In the next two images, two and three bits were flipped. On
Linux systems, the binary difference between files can be revealed using cmp
command (e.g. cmp -b bitrot-original.jpg bitrot-1bit-changed.jpg
).
This deterioration can be caused by a variety of factors that impact the reliability and integrity of digital information, including physical factors, software errors, security breaches, human error, obsolete technology, and unauthorized access incidents. [12] [13] [14] [15]
Most disk, disk controller and higher-level systems are subject to a slight chance of unrecoverable failure. With ever-growing disk capacities, file sizes, and increases in the amount of data stored on a disk, the likelihood of the occurrence of data decay and other forms of uncorrected and undetected data corruption increases. [16]
Low-level disk controllers typically employ error correction codes (ECC) to correct erroneous data. [17]
Higher-level software systems may be employed to mitigate the risk of such underlying failures by increasing redundancy and implementing integrity checking, error correction codes and self-repairing algorithms. [18] The ZFS file system was designed to address many of these data corruption issues. [19] The Btrfs file system also includes data protection and recovery mechanisms, [20] as does ReFS. [21]
High temperature and humidity and fluctuations may cause the magnetic and base layers in a reel of tape to separate, or cause adjacent loops to block together. High temperatures may also weaken the magnetic signal, and ultimately de-magnetise the magnetic layer.
The longevity of magnetic media is most seriously affected by processes that attack the binder resin. Moisture from the air is absorbed by the binder and reacts with the resin. The result is a gummy residue that can deposit on tape heads and cause tape layers to stick together. Reaction with moisture also can result in breaks in the long molecular chains of the binder. This weakens the physical properties of the binder and can result in a lack of adhesion to the backing. These reactions are greatly accelerated by the presence of acids. Typical sources would be the usual pollutant gases in the air, such as sulphur dioxide (SO2) and nitrous oxides (NOx), which react with moist air to form acids. Though acid inhibitors are usually built into the binder layer, over time they can lose their effectiveness.
This article has multiple issues. Please help
improve it or discuss these issues on the
talk page. (
Learn how and when to remove these template messages)
|
Data degradation is the gradual corruption of computer data due to an accumulation of non-critical failures in a data storage device. It is also referred to as data decay, data rot or bit rot. [1] This results in a decline in data quality over time, even when the data is not being utilized.
Data degradation in dynamic random-access memory (DRAM) can occur when the electric charge of a bit in DRAM disperses, possibly altering program code or stored data. DRAM may be altered by cosmic rays [2] or other high-energy particles. Such data degradation is known as a soft error. [3] ECC memory can be used to mitigate this type of data degradation. [4]
Data degradation results from the gradual decay of storage media over the course of years or longer. Causes vary by medium:
Below are several digital images illustrating data degradation, all consisting of 326,272 bits. The original photo is displayed first. In the next image, a single bit was changed from 0 to 1. In the next two images, two and three bits were flipped. On
Linux systems, the binary difference between files can be revealed using cmp
command (e.g. cmp -b bitrot-original.jpg bitrot-1bit-changed.jpg
).
This deterioration can be caused by a variety of factors that impact the reliability and integrity of digital information, including physical factors, software errors, security breaches, human error, obsolete technology, and unauthorized access incidents. [12] [13] [14] [15]
Most disk, disk controller and higher-level systems are subject to a slight chance of unrecoverable failure. With ever-growing disk capacities, file sizes, and increases in the amount of data stored on a disk, the likelihood of the occurrence of data decay and other forms of uncorrected and undetected data corruption increases. [16]
Low-level disk controllers typically employ error correction codes (ECC) to correct erroneous data. [17]
Higher-level software systems may be employed to mitigate the risk of such underlying failures by increasing redundancy and implementing integrity checking, error correction codes and self-repairing algorithms. [18] The ZFS file system was designed to address many of these data corruption issues. [19] The Btrfs file system also includes data protection and recovery mechanisms, [20] as does ReFS. [21]
High temperature and humidity and fluctuations may cause the magnetic and base layers in a reel of tape to separate, or cause adjacent loops to block together. High temperatures may also weaken the magnetic signal, and ultimately de-magnetise the magnetic layer.
The longevity of magnetic media is most seriously affected by processes that attack the binder resin. Moisture from the air is absorbed by the binder and reacts with the resin. The result is a gummy residue that can deposit on tape heads and cause tape layers to stick together. Reaction with moisture also can result in breaks in the long molecular chains of the binder. This weakens the physical properties of the binder and can result in a lack of adhesion to the backing. These reactions are greatly accelerated by the presence of acids. Typical sources would be the usual pollutant gases in the air, such as sulphur dioxide (SO2) and nitrous oxides (NOx), which react with moist air to form acids. Though acid inhibitors are usually built into the binder layer, over time they can lose their effectiveness.