Wednesday, 20 May 2015 00:00

Fifteen myths about data recovery and loss

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Over the years of work in Data Recovery Lab we have amassed a small collection of myths about data loss and recovery. Some of them are actively spread around on different computer and not really forums; so we hope this article will be useful to those seeking help when the drive failed or data is lost. So, a posting about how NOT to make a difficult situation even worse.

1. Shockproof housings for external drives

This is a marketing ploy - rubberized housings do not save a hard drive from damage, for example, after a fall. They, of course, look beautiful and impressive, and make the hard disk itself look reliable which instills confidence in the customer - that is why he purchases them. However, they only slightly reduce the overstress on HDD parts during impact or fall. This can save provided that the height is low (up to about 50 cm for 2.5" hard drives, up to 20 cm for 3.5" drives), and the drive is turned off. When turned on, the drive almost always breaks down, because max overload on a working drive is 5-7 times less than on the off one. We conducted a crash test for 2Tb drives by Samsung, Hitachi, WD, Seagate. We dropped them when turned on from a height of 5 cm, then 10 cm, then every 10 cm. All drives except Samsung broke at 15 cm. "Samsung" broke at 40 cm owing to rubber dampers between the drive itself and the housing. All drives were external 3.5" ones.

2. If the hard drive malfunctions, knock at it with, for example, a screwdriver at the boot time

To achieve such an effect you can also tap the drive on the floor. The only thing is that it will not be a repair for your drive. As a result of such workaround, small particles of what breaks off inside will scratch the drive, and it will be impossible to recover the data. You can destroy data especially reliably, if you turn the drive on and then drop it from the height of about one meter (see previous paragraph). Nice notches will appear on its surface, after which it will be impossible to recover data.

3. There is vacuum inside a hard disk

- Or, as some of our customers say, "there is inert gas". So if you happen to disassemble the hard drive, you will be sucked into it due to the fact that the air of the room will be sucked in the vacuum space of the hard disk. This a good myth; I'd hate to dispel it: maybe, this could dissuade some of the "do-it-yourselfers" from making their data "unrecoverable" by dismantling the drive? However, in fact, there is just clean dust-free air inside the drive, so that nothing gets in the space between the drive and the head.

10-15 years ago drives were indeed made completely sealed; you could even spill water on them, submerge, then wipe off the electronics board and use it again - the water would not get inside. In modern hard drives, there are always holes in HDA body or top cover with the notice «DO NOT COVER THIS HOLE»; underneath you can find air filters against undesired particles. This change was made by manufacturers due to implementation of the new production technologies, falling production costs and other reasons. If such a drive is dipped into water, it will get inside the HDA through the filter.

4. I can ensure the "clean room" at home and dismantle the disk

For example, it is possible to disassemble and assemble the drive in the bathroom, if the bathroom is washed clean upfront. This is one of our favorite misbeliefs. Even an experienced professional can hardly cope without a convenient table, chair necessary supports, tweezers, screwdrivers and removers. But a user will not organize a complete workplace at home in the bathroom, equipping it with all necessary tools, at least for economic reasons, because people usually attempt to repair drives by themselves just to save money. As we wrote in the previous posting, the drive is assembled and disassembled in a special dust-free room, and the specialist working with the drive is dressed in special clothes. On the other hand, if you wash the bath thoroughly... No, we do not still advise doing it.

5. If BIOS or OS do not see your hard drive, it means it is broken and must be disassembled

In fact, if you can not "talk to" your drive in software language, you use the specially designed hardware, which starts up a "dialog" with the problem drive. At this level, you can fix bad sectors, replace malfunctioning software of the drive, retrieve the data from bad clusters and transfer it to other media, etc.

The drive can be disassembled only when physically damaged.

6. The hard drive must be heated/cooled to work better

There is the servomotor in the hard drive, which allows the more accurate adjusting the head position relative to the drive, and there is a upper layer of the drive. There must be a certain gap kept between the head and the drive. But sometimes the head starts to malfunction. A little knowledge is a dangerous thing: someone came to the idea that it is caused by natural drive heating and all the rest things about expansion and contraction of materials, and that it can be fixed by cooling/heating. As a result of "freezing" the hard disk, condensate is generated between its platters. At the very first turning on after such cooling, the drive may be irreversibly damaged. On the photo at the beginning of the post - an example of what happens to a drive when it is turned on after 1 hour of being in the freezer.

7. Data is recovered by a special "data recovery machine"

The myth takes its rise in the human imagination. The faulty drive is allegedly pushed into a machine which kind of influences it by magnets, and the data, that "was scattered all over the drive and thus could not be read", line up again. In fact, data recovery is carried out by using either software or special devices or the "clean room" (read as dismantling the disk). The data can not be recovered back on the physically damaged drive; you need a donor drive for that.

8. I don't need data recovery specialists, because there are free utilities

Utilities will not help if the drive is damaged physically. You should recover data at least to a "good" partition, but recovering to a new media is better.

9. The drive can be repaired

You can change its program, and then find and hide bad clusters. But this will not repair the drive. The data must be recovered to the new drive. That is why when you turn to a data recovery specialist, he uses a "donor" - an operational device to which data is recovered. If someone promises to repair the dead drive, he is likely to do what is described in this paragraph: but this will not make your drive either new or "repaired", and the further working with it will threaten your data safety. If its hour has struck, it has struck.

10. I can take out a platter from the faulty drive, take an operational drive, pull out a platter from it, put the platter with the data in there and read all

For this to work, you have to guess the drive`s own program, drive series - well, relatively speaking, to take exactly the same drive and put in the platter from exactly the same drive. However, this does NOT make working in a specially prepared room and availability of equipment unnecessary (see paragraph 4 on the "clean room").

11. The professional data recovery is expensive; prices start from 25,000 rubles

Some companies would like you to believe in this myth. In fact, the price is made up of a variety of factors. How difficult it would be to recover the data depends on what you did with the drive after it had refused to work. Shut down your computer (so that it does not attempt to "self-repair" the drive), do not use utilities, do not disassemble the drive - and perhaps we will be able to recover the data without recourse to "the clean room", which is the most expensive case scenario. When the hard drive is physically operational, the cost of data recovery should be about 1500 rubles. The diagnostics should be performed for free, and if, for some reason, the data recovery failed, you do not have to pay anything.

12. SSDs are unassailable

Unlike a hard drive, there are no moving elements in a solid-state drive, and nothing particularly can spin or break. However, this does not mean that you can play football with them; they are not safe from crash. In an effort to make them smaller in size and larger in capacity, manufacturers sometimes forget to make them more reliable, too. In addition, these drives are protected from an ordinary fall or drowning in the same way as any hard drive: only by your own prudence and luck. In addition, they are more expensive and have a limited number of overwrite cycles. Moreover, SSDs released before 2009 were often slower than HDDs, especially after a long-term use.

13. If a manufacturer claims that a hard drive can run 500,000 hours, it will be operational for the next 57 years and will not break down

4% of such drives fail within the first year. The fact is that the time claimed on the package is the estimated time of how long theoretically a drive of this model should be operational. And there is not a single word saying that exactly your hard drive will work for so long.

14. The more you pay, the better your data recovery will be performed, so it is necessary to choose the most expensive recovery

The data cannot be recovered "better" or "worse". It can be either recovered or not recovered. Special software, special devices, and finally tools and "the clean room" are used for that end. Devices for data recovery are expensive in themselves, but are not different enough to strongly influence the difference in prices for data recovery services. These are all promotion and marketing ploys.

15. You can recover data after a complete overwrite using remaining magnetization

This myth comes from the past, when computers were large and hard drives were small. There was a byte write on hard drives of up to 1Mb, that is, simply put, one drive cluster when being written was equal to one byte. In that case, it was making sense to look for the remaining magnetization and recover data using it. Now that the data is written sector-wise, and there are 512 bytes per sector, and the data density is tens of gigabytes per square centimeter, it is impossible any more.

Last modified on Wednesday, 20 May 2015 13:14
Data Recovery Expert

Viktor S., Ph.D. (Electrical/Computer Engineering), was hired by DataRecoup, the international data recovery corporation, in 2012. Promoted to Engineering Senior Manager in 2010 and then to his current position, as C.I.O. of DataRecoup, in 2014. Responsible for the management of critical, high-priority RAID data recovery cases and the application of his expert, comprehensive knowledge in database data retrieval. He is also responsible for planning and implementing SEO/SEM and other internet-based marketing strategies. Currently, Viktor S., Ph.D., is focusing on the further development and expansion of DataRecoup’s major internet marketing campaign for their already successful proprietary software application “Data Recovery for Windows” (an application which he developed).

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