Bad Sectors on Hard Disk Drive
Bad sectors can occur randomly in a hard drive and render it unreadable by the computer. The disk is divided into multiple sectors for the proper and efficient hard disk operation. Many bits of computer information are stored in these sectors on the hard disk. When the drive is healthy, all the bits and bytes of data on the platters are accurate and is the correct representation of the original information.
When errors occur due to some random sectors becoming bad, the written data bytes in these sectors area would surface out as bad, corrupted or unreadable and lost. Most time users could experience the computer “hang” symptoms when bad sectors are accessed on the hard drive. The computer may display error codes such as cyclic redundancy or CRC errors.
Bad sectors are generally not correctable nor repairable so it is important to make good copies of data before the hard drive deteriorate to a worse condition.
Causes of bad sectors are often attributed to the magnetic properties of the platter losing its strength and effectiveness to retain stored information on the hard disk. Over time the weakening of magnetism is inevitable due to prolonged usage.
Other causes could be due to mechanical failures, power instability during read/write disk operation or sudden power shutdown. Mild head crash can affect the disk platters and also cause bad sectors. Bad sectors could also be signs that hard disk crash is drawing near so take immediate action and have all the data back up as soon as possible.
An important point to note is that bad sectors could also spread across the entire hard disk and render it totally inaccessible or corrupted. For hard drive having few bad sectors, the computer file systems can usually detect, fix and repair them on its own. If there are critical data on the hard drive that has many bad sectors, it is proper to seek for professional data recovery expert services to salvage as much data as possible.
A hidden cause of bad sectors could be triggered by bad parity checking bits becoming corrupted inside the sectors. Corrupted parity bits can change the checksum when the data streams are read incorrectly and processed by the computer. For such cases, proprietary methods of data recovery can be employed to detect and correct the corrupted parity bits to restore the data loss in the sector.