Why, or how, do files become corrupt?

Gamma rays cause these sorts of problems. A friend proved it to my by pointing out that hard drives are not protect from gramma rays. Seemed reasonable to me :). It was the only reasonable explain for the problem I was having... :)

My son has an Acer 3000, and suddenly it won't power on at all. We have charged it for a long time, and tried it with and without the power cord, but it still won't come up. Can you recommend anything to try that won't cost anything? I am struggling right now financially. Do you know of any moonlighting jobs using your pc where you can work from home in the evenings or on the weekend?

How can I be sure that my backup isn't copying corrupt files to begin with? Is that what the "verification" process handles?

It depends on the kind of corruption. If it's a physical problem, as outlined in this article, then reading the disk will show errors and is likely to return different data each time the bad sector is read - thus when the verification stage comes along the comparison it does fails. If the data is physically ok, but has been corrupted in some other way (some rogue program went in and turned all of your "a"'s into "b"'s) then the verification phase will simply verify that the corrupt data has been backed up properly.

30-Dec-2009

I believe that if gamma radiation (very high energy x-rays) can cause data coruption on a HDD you have a more serious problem. Your exposure to the same radiation.
As it is gamma should have no effect on a HDD.

Moving a drive while it is in use or dropping it can an most likely will cause problems as Leo suggested.

Again if you have a gamma source near enough that you think it could be causing your data corruption then you yourself are in some danger.

I've actually had a respected electrical engineer I know comment that "cosmic rays" (no idea if that's gamma or not) can, in fact cause problems. It's very rare, but the same cosmic rays that we simply live in by virtue of living on planet earth can, apparently and very rarely, interfere with the micro-electronics we now rely on every day. Just one bit "knocked out of place", so to speak, can be completely benign, or if it's the wrong one, cause a system crash. It's extremely rare as I understand it, so I wouldn't run around blaming all your system crashes on cosmic rays, I just thought it was fascinating because it's so counter-intuitive.

30-Dec-2009

It seems that a careless shutdown or accidental power loss can cause file damage...can you comment?

Same basic idea: sectors can fail to be written completely as the power disappears from the drive. Add to that the fact that the operating system may not have the opportunity to write all data to the disk and everything from incomplete files, to completely corrupted directories can result.

30-Dec-2009

Correct powerloss can cause data loss. Windows may not have flushed all of a modified file's contents to disk even if you have done a "close" on the file (depending upon the details of how you opened the file). Thus, it is easy for a poorly timed powerloss to cause data you thought was hardened to disk to be lost. This problem should not exist for a shutdown, as the operating system knows to flush those buffers during that process. A good/professional programmer knows how to take steps to prevent such data losses (but most "programmers" are not good or professional in their profession ;-).

well, I see, yet again, you emphasise the point of 'backup'. however, my question is, should one backup only the computer or laptop or even the online content such as, email IDs, social bookmarking profiles. & much more?

would my emails not be secure with a paid account with yahoo? should i sign up a contract with a third party site that claims to make a backup of all my online content? should i trust a site such as:

backupify.com

which is a recent entrent in the 'data backup' industry?

Your help would be really appreciated in the matter.

Thanks yet again for such a wonderful resource!

Frank, how in the world would a person be exposed to gamma rays in normal, everyday circumstances?

By virtue of living on planet earth. Gamma radiation is one component of Cosmic Radiation ( http://en.wikipedia.org/wiki/Cosmic_ray ). Miniscule amounts, but there.

31-Dec-2009

Alpha, beta and gamma rays are everywhere around us. Part of these rays are coming out of the earth (e.g. alpha rays are emitted by the gas Radon which leaks from cracks in the shell of the earth) and another part is coming from outer space. Compare it to the light coming from the sun. Cosmic rays may contain high energetic neutrons, protons, electrons and so on. Some places on the earth are absolutely unfriendly to life and just as you may develop cancer after exposure to sunlight you may also develop cancer by breathing air with Radon in it.
As a scientist I do not suppose hard drives to fail by a normal exposure to the rays mentioned above--this story is probably an easy way out for someone who can not think of anything else. What about the rays used at airport security checks? They won't kill a HDD as far as I know.

I always come across quite a number of crc errors and data corrupted every 1 out of 5-6 files I downloaded. At first, I could unRAR those files, but the next time I tried to do that, the files turned corrupted, crc errors or checksum does not match when I made a checksum file. Mr. Leo, would you mind commenting on this issues. Is my hard disk drive starting to fail or is it very common now that datas can be easily corrupted in hard disk after being kept for a period of time? Is there a way to minimize such problem as it started driving me nuts.

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