Hard Disk Drive Myths Debunked!

[power]

<quote>Hello power,

Actually, I covered this in Myth #17.

It is possible to format or use some software to "hide" bad sectors but it doesn't really repair them. All a low-level format or that software you mentioned do is replace bad sectors that they find with free sectors on spare tracks found in every hard disk. This is essentially what happens to every hard disk at the end of the manufacturing process.

As you mentioned above, there is a limited number of bad sectors that the software can "repair". That is because the number of spare sectors is limited. Once the spare track is used up and there are no longer any spare sectors, then low-level formatting or that software will not be able to hide additional bad sectors.</quote>

If you suspect that your disk drive is damaged and contains bad sectors, don?t hurry to throw out the disk and don?t think that your important information is irretrievably lost. Take advantage of HDD Regenerator - the unique software program for regeneration of hard disk drives. Almost 60% of all damaged by bad sectors hard drives have incorrectly magnetized disk surface. Our researches have been fruitful and we have found algorithm which is special sequence of high and low level signals. These signals are generated by the software and they switch damaged surface. Even low level formatting is not able to handle this task! HDD Regenerator regenerates bad sectors by magnetic reversal. If your hard drive is damaged by bad sectors, the disk not only becomes unfit for use, but also you risk losing information stored on the disk. HDD Regenerator will regenerate your hard disk. As a result, not readable damaged information will be restored. With all this going on the existing information will not be affected!

if you actually clicked the link i put in and read the above paragraph quoted from the website read the above you would note that hdd regenerator restores the bad sectors unlike what the software in something like hitachi's dft does making the data in the bad sectors readable again they are actually restoring the bad sectors, i understand what most software does and what you have based your myth on however hdd regenerator does not work the same way! If it did regenerated drives would need to be reformatted and have a loss of data this is not the case with hdd regen quite often we will have drives which have 1-30 bad sectors at the start of the drive and they will not boot into windows and just get stuck in a rebooting loop, drive regen will recover them and the drive not only is usable again but will boot into the OS, you can dismiss this software and place it into the basket with all your other hdd repairing software or you can try it for yourself next time a drive of yours develops bad sectors.

[elkinm1]

Hi, I once got a refurbished hard drive which came with bad clusters after a format. Later on I reformated it but the bad clusters dissapeared, but then with a detailed norton surface scan they showed up again. After that I kept finding more and more bad clusters but the drive was working fine. Well within a total of two months the drive died completely. Since then I hate refurbished drives and any drive that came with bad clusters I instantly return.

Basicly a WD 80GB SE HD recently died on me with a single loud click without any warning of any kind or any real noticable strain. RMA dep. says they send out refurb drives which imedietly makes me nervous as its like storing data that I am begging to lose, but I don't want to waste the drive.

So basicaly any idea why the drive failed and how crapy are WD refurb drives.

I know it is not a direct myth but it nicely covers some myths.

Thank You

[crackerjack]

Ifoot2,
its a fair point, the magnetic domains will tend to 'blur' up over time. Really depends on the quality of the media and the 'difficulty' of the pattern the domains form on the media as to how long it will be readable for.

As far as disk orientation goes, once upon a time, running a hard disk inverted was a big no no. It would cause abnormal bearing loading and could cause premature failure. I'm not sure how FDB based drives will cope with being run upside down, depends on how the assembly is presurised. If it only pumps up one side, then running it upside down may have nasty consequences.

[CypherPhuck]

Great article as usual, Adrian! Keep it up!

Originally Posted by crackerjack

Pitty there are several myths emerging from this article. How so?

Well, for a start, there is no 'spring' to return the head assembly to the 'landing' region on power fail. There is no spring at all. The heads are actively driven to the landing zone by dumping the energy from the spinning platters via a few fets into the coil. This ensure that after power is removed, the heads are always run home, and the platters are breaked with in a reasonably short time.

There is also no physical lock to keep the heads in the landing zone. Its all done with magentism.

If you popped the top of a defunct drive and moved the heads out of the park region to break the magnetic lock, they will just sit there. If you unplug the spindle motor and rotate the platters at some speed with the heads out of the landing zone, the heads will fly and may float in one direction due to air pressure, but thats it.

There are other technical errors in the article, but someone else can post them.

You can't just say that he is spreading myths himself, crackerjack. You have not provided a single shred of proof.

But I agree with you that many hard disks now use energy from the spinning platters to move the heads but to say that Adrian is wrong is also wrong.

I point you to this guide by StorageReview.com.

Modern voice-coil actuated hard disk drives are all auto-parking. On some disks, a weak spring is attached to the head assembly that tries to pull the heads to the landing zone. When power is applied the actuator is able to overpower the spring and position the heads normally. When the power is shut off, the electromagnetic force from the voice coil abates, and the spring yanks the heads to the landing zone before the platters can spin down; this can sometimes be heard on older drives as an audible clunk when you turn the power off. Other disks use a different mechanical or electronic scheme to achieve the same goal. Some even make use of the rotational energy remaining in the spindle motor to move the heads off the data surface when the power is cut off! This means that modern hard disks will automatically park their heads--even in the event of a power failure--and no utilities are required.

Here is the link - http://storagereview.com/guide2000/r...ctParking.html

You have the technical knowledge, crackerjack. But you might want to soften on your approach. I have known this site to be really acceptive of constructive criticism. Just tell them if they made any mistakes. There is no need for any macho show off of technical expertise.

[TungstenBoy]

Originally Posted by crackerjack

Ifoot2,
its a fair point, the magnetic domains will tend to 'blur' up over time. Really depends on the quality of the media and the 'difficulty' of the pattern the domains form on the media as to how long it will be readable for.

As far as disk orientation goes, once upon a time, running a hard disk inverted was a big no no. It would cause abnormal bearing loading and could cause premature failure. I'm not sure how FDB based drives will cope with being run upside down, depends on how the assembly is presurised. If it only pumps up one side, then running it upside down may have nasty consequences.

harrrrr.............r u sure??????.............the magnetic field in the hard disk can blurrr????? .........where did u read dis....??????

[zy]

might be true... i wonder what happen if you place a very strong magnet to the hard disk .. ..

floppy disk data sure.. gone..

[coreying]

Myth #2 :
Formatting a hard disk causes a layer of *whatever* to be deposited on the platter surface, causing bad sectors to form.

Truth :
Formatting will not deposit any layer of "anything" on the platter. The hard disk is a sealed environment so there is very little dust inside the hard disk. Even if there is dust, why would formatting deposit anything on the platter?

Your article was rather good... but as with the previous comments about too much power causing failures and other generalised statements with are not necessarily wrong, but not right either (like landing zones, and orientation of hard drives), you have made another incorrect comment here.

Hard drives are NOT sealed! Yep... that's correct. Check it out for yourself, there is usually a little hole on a harddrive which is visible... it sometimes even says something like 'do not cover' etc. It's not always visible to us without pulling the harddrive apart, but it is there.

The reason ?
As soon as you start moving the platters and heads, friction in the environment (ie, platters moving in the air) causes heat, and also heat from the bearings and other electronic/mechnical devices causes the air to expand. Thus it needs a way to escape.


Also, to add to the cheap power supplies debate - there are studies available which shows that power causes many hardware failures (not just with computers). It's not only the oversupply of power, but the undersupply or _irregular_ supply of power. It doesn't usually cause problems with are immediate or obvious (ie, platters spinning up and down etc), but over time causes unnecessary stress on electronics and mechnical items and thereby increasing the likelyhood of failure. Some studies claim that companies using good quality powersupplies AND power conditioners have up to 80% less hardware failures than companies who arent.

I will also support power's posts about the software utility called HDD Regenerator. Doing technical support in an environment with over 9,000 computers (laptops/desktops/servers), this piece of software has proven invaluable. The fact that it can actually restore data from sectors which have been marked bad, all without formatting, is great. It doesn't work all the time, but considering it's doing something you'd have previously thought was impossible for any software to do, it's awesome.
Anyone who does not look into that further is only causing themselves a disservice.[/b]

[peaz]

harrrrr.............r u sure??????.............the magnetic field in the hard disk can blurrr????? .........where did u read dis....??????

Yup TB, it's correct that the magnetism on the disk platters can 'blur' after a long time. This is especially true if the section of the disk do not gets re-written over a long period of time. You see, when u read and write on the disk, the sector gets remagnatise back. So it sort of like 'recharging it's magnetism power'... sort of. That's why some ppl actually recommend defragmenting your hard disk often becuase it moves your files around and in doing so, it newly placed data is written with 'newly charged' sector...so to speak.

I will also support power's posts about the software utility called HDD Regenerator. Doing technical support in an environment with over 9,000 computers (laptops/desktops/servers), this piece of software has proven invaluable. The fact that it can actually restore data from sectors which have been marked bad, all without formatting, is great. It doesn't work all the time, but considering it's doing something you'd have previously thought was impossible for any software to do, it's awesome.
Anyone who does not look into that further is only causing themselves a disservice.

I remember a utility called "HD" a long time ago with the capability of recovering data from bad secotes of floppies. TO me and my friends, that utility was like 'the god of utilities', we made sure everyone had a copy.. no, TWO copies in case one went dead, we carry them around in a floopy like a true geek would, and we copied it to any PC we encounter... I believe this is similar with the HDD Regenerator does as well, it tries to read over the bad sector countlesss times in an attempt to retrieve the data from there.. and yes.. i do agree it works.

But I've been in discussion with Adrian on this already, in the guide, he actually meant that a real bad sector... irrecoverable ones, cannot be saved. This means physically damaged platters. The Myth was that a reformat or recovering utility that low level formats 'seems to rejuvinate' these sectors when what they really do is to use the spare track. He didn't really dispell off this regen utility that REALLY read from the bad sector in an attempt to recover the real data there.

[zy]

Originally Posted by coreying

Hard drives are NOT sealed! Yep... that's correct. Check it out for yourself, there is usually a little hole on a harddrive which is visible... it sometimes even says something like 'do not cover' etc. It's not always visible to us without pulling the harddrive apart, but it is there.

The reason ?
As soon as you start moving the platters and heads, friction in the environment (ie, platters moving in the air) causes heat, and also heat from the bearings and other electronic/mechnical devices causes the air to expand. Thus it needs a way to escape.

yes thats true... it has a hole with special filter which prevents dust from entering

[lillepede]

> Some bad sectors are "virtual" bad sectors that can be repaired by
> formatting the hard disk.

I think this misconception is founded in that some harddisks (like IBMs) contain an extra area of sectors, which can be used instead of bad sectors. This way you retain the available storage eventhough sectors have gone bad. Well, at least until the disk runs out of extra sectors.
This is the case with the 75GXP series, which I had the "pleasure" of dealing with.
You need to use IBM-tools and to do a low-level format for the swap to occur.

regards/lillepede