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A hard disk drive failure occurs when a hard disk drive malfunctions and the stored information cannot be accessed with a properly configured computer. A hard disk failure may occur in the course of normal operation, or due to an external factor such as exposure to fire or water or high magnetic fields , or suffering a sharp impact or ...
Hard disk and other storage drives are subject to failures (see hard disk drive failure) which can be classified into two basic classes: Predictable failures which result from slow processes such as mechanical wear and gradual degradation of storage surfaces. Monitoring can determine when such failures are becoming more likely.
Many errors are detected and corrected by the hard disk drives using the ECC codes [17] which are stored on disk for each sector. If the disk drive detects multiple read errors on a sector it may make a copy of the failing sector on another part of the disk, by remapping the failed sector of the disk to a spare sector without the involvement of ...
When a hard disk drive fails, the importance of getting the data off the drive is the top priority. The longer a faulty drive is used, the more likely further data loss is to occur. Creating an image of the drive will ensure that there is a secondary copy of the data on another device, on which it is safe to perform testing and recovery ...
On a hard disk drive, the click of death refers to a similar failure mode; the head actuator may click or knock as the drive repetitively tries to recover from one or more errors. These sounds can be heard as the heads load or unload, or they can be the sounds of the actuator striking a stop, or both.
Mac OS 8.6 and later include the version number in the splash screen (for example, "Mac OS 9" in big black text). On early Macs without an internal hard drive, the computer boots up to a point where it needs to load the operating system from a floppy disk.
In the normal operation of a hard drive, the detection and remapping of bad sectors should take place in a manner transparent to the rest of the system and in advance before data is lost. There are two types of remapping by disk hardware: P-LIST (mapping during factory production tests) and G-LIST (mapping during consumer usage by disk microcode).
Modern hard drives feature an ability to recover from some read/write errors by internally remapping sectors and performing other forms of self-test and recovery. The process for this can sometimes take several seconds or (under heavy usage) minutes, during which time the drive is unresponsive.