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What causes HD bad sectors?

By galahad04 ·
Hello,

I know that when running Scandisk to check the physical clusters on hard drives and disk drives, sometimes clusters will be reported as bad/damaged sectors on the hard disk (upon which Scandisk quarantines that portion of the disk as unusable). What I would like to know is what causes these bad/damaged sectors? (In other words, how and why do disk sectors become damaged?)

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What causes HD bad sectors?

by qsr In reply to What causes HD bad sector ...

It must not be always a defect of the HD. Scandisk often brings you cluster-damage-reports even if this doesn't corresponds to the truth.
That's the result of that Scandisk often get's problems by reading type of datasystem, partition/HD-size. I know of problems occured with any operating system - whereby all of those were solvable.
As it comes to real HD-damages I know only of older HDs which became defect - results f. e. have been overvoltage of the system, agecauses (up to 10 years old) etc.

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What causes HD bad sectors?

by galahad04 In reply to What causes HD bad sector ...

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What causes HD bad sectors?

by rgrowcock In reply to What causes HD bad sector ...

Several things can cause bad or damaged sectors, but they all relate to the same thing, power loss. If your system is shutting down and you turn it off before it is done shutting down, that can cause bad spots. If a power surge or loss happens, same results. Generally, that is how a lot of bad sectors come about.
The best thing to do is have a UPS, even if it's a small one attached to your system. It will not only protect from a power outage, but it will also maintain a constant level ofpower. Power fluctuations are common all over the country, not just in the West. Another thing to do is when shutting down your system, make sure it is COMPLETELY off before turning off the power to it.
Hope this helps!

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What causes HD bad sectors?

by galahad04 In reply to What causes HD bad sector ...

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What causes HD bad sectors?

by Ann777 In reply to What causes HD bad sector ...

Generally any sort of corruption can be caused by intermittant types of problems:

An improper shutdown or reboot without closing down all the programs, anything that causes the hdd heads to land on the platters (power failure or flux, or dropping the laptop computer), any microscopic dust getting into the drive, etc. Any of these (and more) can cause bad or damaged sectors.

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What causes HD bad sectors?

by galahad04 In reply to What causes HD bad sector ...

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What causes HD bad sectors?

by grump In reply to What causes HD bad sector ...

You question is How and Why do disk sectors become damaged..
Scandisk simply trys reading sector by sector of you hard drive, if it has a problem reading the complete sector is wants to flag the sector bad.
The sector is not always bad or DAMAGED. When data is written to a sector there is update information rewritten in the FAT table, File Allocation Table . If the Information in the FAT does not match the check byte in the sector PROBLEMS.
Most problems are caused buy the end user, pressing the RESET button when the system is not responding to an impatiant user. Powering of the computer while the HD is writting data.. Without having knowledge of how the HD data is stored and what takes place from track N sector aspect the end simplybeleives that when scandisk flags a disk sector bad that the hard drive is starting to fail and need to replace it..
We simply don't have enough space here for me to explain in great length how the HD works and what and why bad sectors.. Running defrag to will rewrite files which are fragmented and make read/write more effective as time goes on.. There are technical manuals which will explain Head Clyinder / Track Sector theroy if you really want to know what and why bad sectors. Next time you run across a bad HD take it apart an see what is inside.. I sure hope that I have you in complete confusion... But you asked a highly techinal queston with no simple answer! (This comes from twenty years working on computers, both large and small.)

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What causes HD bad sectors?

by galahad04 In reply to What causes HD bad sector ...

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What causes HD bad sectors?

by csmith In reply to What causes HD bad sector ...

There are only one cause true for bad sectors.
The Read/Write Head striking/hitting the platter.
The head "flies" above the spinning platter on a very thin layer of air, which is caused by the spinning disk. (Think Surfing)
Vibration, Dirt, etc. cause head contact, and cause damage to the platter.
This is easy to see on a bad HD. (The old 40-100 Meg Drives are best for disassembly, because the old platters are softer, and the damage is more obvious.)
The false bad sectors that you see on many drives are caused by power spikes, etc. causing false writes.
That these are false, can be seen by using the Disk Utility from the manufacturer. (Free Download.)
If you are getting excessive bad sectors reported, don't forget tho check the Power Supply.
Regards, Chris

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What causes HD bad sectors?

by galahad04 In reply to What causes HD bad sector ...

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