Hard Drive Myths - Bet you've heard some of these old Chestnuts . . .

Posted in Category(ies):  Data Recovery

Hard Drive Myths…BUSTED


In the Data Recovery Field we continually come across two very common scenarios:

  • Hard Drive Failed and they Tried to fix it themselves from Solutions gleamed from an Internet Search.

  • Their IT Company / Individual tried to be helpful & “save them money” by doing the same Internet Search and tried doing a Data Recovery for them from Solutions gleamed from that same Internet Search.

Both these routes, invariably, have the same result – the make the Data Recovery job more difficult for us to do and, ultimately, make the same job more expensive on you. Essentially, it boils down to how important your data is. If it’s just something you’d like to have, and not necessarily something you have to have, then there’s no harm in attempting a data recovery on your own. However, if your data is critical, or priceless, then avoid following any of the tips you find online or handing your hard drive to your IT guy who will try and follow the same Tips. Remember an IT Resource / Computer Repair Shop IS GENERALLY NOT a Data Recovery Shop – it would be the same as asking your GP to do Open Heart Surgery as opposed to asking him to refer you to a Cardiac Surgeon. Let’s have a look at a few “Urban Myths” out there regarding Hard Drive Recovery and Data Recovery in general.


Hard Drives Are Air Tight

Hard drives are actually NOT air tight – in fact they require Air within them to operate in the first place. When a Hard Drive is first powered on, the heads are actually locked in place until enough Air Current is generated to keep the heads flying at a steady and safe height above the platter surfaces. This principle is referred to as the “Air Bearing”. In fact, if Hard Drives were so sealed that there was no way to equalize pressure between the interns and the outside world; they could not even be transported by Aircraft – they would be damaged / explode. That is why so many drives have a small hole on the casing, and it usually instructs you not to cover it! So the myth that drives are sealed air tight is totally false. Incoming air passes through an intake filter which offers substantial filtration for the incoming air, to keep contaminants out. However, we have seen, on some newer hard drives, which are so poorly constructed that the breathers are not filtered very well. It’s actually quite common now to open up brand new drives and find the, supposedly sterile, platter surfaces littered with contaminants such as small specs of dust! In the Data Recovery Field, some Data Recovery Experts are claiming that these contaminants are what cause some newer drives to fail prematurely withot other factors being involved e.g. being dropped etc.


Hard Drive In The Freezer

This is an old chestnut – surviving from the days when, due to less exact manufacturing tolerances, putting your hard drive in the freezer might actually have allowed you to recover your otherwise inaccessible data from. There was actually a time a few decades ago (remember ST506?) when hard drives, sometimes, actually did respond well to being frozen. The change in Temperature would cause the various components and clearances within the failed hard drive to expand/contract - you could have issues with the heads, or motor bearing. Popping it in the freezer for a couple of hours would allow you enough expansion/contraction to change the drive dimensions sufficiently (due to lower temperature) to gain access to the data for a short period of time. With the exact manufacturing tolerances of hard drives today, the freezer does nothing but lessen any chance you might have at recovering your data. As we stated earlier; hard drives are not air tight – imagine what moisture-laden warm air flowing into the drive after it comes out of the freezer causes? – Condensation. So even if you have the drive wrapped up in a ziplock bag, aluminum foil, or whatever, as soon as the drive starts to warm up, the cold air that has gone into the drive through the intake, is going to start to condense and form moisture on the platter surface.


Swapping PCB / Logic Board.

IT Guys are the major culprits here! Another quick fix that people think they can try, especially when their hard drive has a bad logic board (i.e. the drive will not power up), is they try to swap the board out for one on a similar drive. In fact, on 1-2 occasions we have seen drives being returned to the owner, by the IT Company / IT Person with the new board on the drive with the original board having been dumped. Net Effect – Data, more often than not, is gone forever and Data Recovery is not possible! controller boards have specific chips on them that store data that allows the hard drive to function properly. These are called “adaptives”, and they work with the firmware of the hard drive, in what is typically referred to as the hard drive’s system area.  Each drive has it’s own unique set of adaptives, the most critical of these adaptives are what is known as the P-List ( Production List ) and G-List ( Grown List ). These two lists contain lists of sectors that the hard drive cannot use for data storage and are completely unique to that individual hard drive. This information is also saved on the PCB, and when you replace a board with the adaptives from another drive, there is a mismatch and the drive is unable to function. For Data Recovery purposes, more often than not, it is essential to have the Original PCB on the drive.

Posted on Wednesday, 5 November 2014  |  By John O'Shea
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