What would happen to your data if: a. you backed your SUV over your laptop? b. your laptop spent two days in a sunken cruise ship submerged at the bottom of the Amazon River? c. firefighters rescued your computer’s scarred carcass from a flaming warehouse?
Data recovery specialists restored the lost data in all of the above situations. Fire, flood, and road rage is all in a day’s work for these knights of the byte.
Michael Peltier is the Senior Data Recovery Engineer for Data Recovery and Reconstruction in Tucson, Arizona. He has stories to tell and suggestions to offer.
But first, some background. Drive units contain read/write heads that transmit data to recording platters. The head flies above the platter, separated by a painfully thin cushion of air. Measured in microns, the thickness of a human fingerprint is many times higher than the head’s flying height. If the head makes direct contact with the recording platter, particles are knocked off the head and the platter and are caught in the air cushion where they grind off the platter’s recording media. The drive can corrupt in as little as fifteen minutes or it could take several days.
Peltier reminisced about the customer who applied “a few drops of oil” inside the drive enclosure because the motor wasn’t turning. The enclosure was saturated with oil and the oil prevented the head from flying. The recording surface was ground clean. “A few drops! He should have added a dipstick!” Peltier said.
Then there was the time he discovered a family of ants had taken up residence in a drive enclosure.
However, obsolescence is the typical culprit. All drives will fail eventually, but a mixed bag of conditions causes premature drive failures — heat, water, impact, power interruptions, viruses or environmental contaminants.
While fire can cause heat damage, overheated equipment is the most likely cause. If the ambient (i.e. room) temperature becomes too high, changes in air pressure will reduce the air cushion’s thickness. The read/write head contacts the recording platter and corruption occurs.
Physical shocks or high vibration levels cause similar damage.
Environmental contamination usually occurs if the seal that goes around the drive is damaged. (Not all drives have these seals). With the seal damaged, particles in the air or cigarette smoke can find their way between the head and the platter where they will grind away the recording media.
Water damage occurs because contaminants in water are corrosive to the metals found inside the drive, causing microscopic pitting.
Power interruption also causes damage. Sudden power failure or lightning strike can cause the drive to lose RPMs (revolutions per minute). This causes air pressure to drop, which in turn reduces the head’s flying height.
Viruses can create havoc through software damage.
Peltier suggests the following practices will increase your chances of data recovery:
1. Backup, and store your backup data off site.
2. Do not apply power to a damaged drive. Power diminishes the ability to recover data.
3. Power down immediately if your drive emits grinding, scraping or clicking sounds. Continuing to write to the media will increase the amount of corruption and will destroy clues or “Rosetta stones” that data recovery specialists use to restore your data.
4. Utilities such as Scandisk and Norton Disk Doctor are useful for repairing minor problems, but if used for a serious problem, they decrease the likelihood that a recovery specialist can restore the data. Peltier explained that these utilities sometimes interpret the drive geometry incorrectly. “Then, it uses what it thinks is available drive space for scratchpad operations, and can end up overwriting actual data that is located there. This makes quite a mess.”
Say “No” if Scandisk or another utility asks you if you want it to attempt to repair damage. Windows users can discover the extent of the damage by going to the command prompt and running checkdisk WITHOUT the /f switch. “If there are 4-5 errors, roll the dice and let Scandisk fix it. If there are hundreds or thousands, contact a data recovery professional.
5. Large files are more at risk of corruption than smaller files. If possible, separate your work into smaller files.
6. Never open the drive enclosure. One speck of dust can destroy hundreds of sectors, and just loosening the screws can put the drive out of alignment so the circuit board no longer recognizes it.
File recovery cannot be guaranteed, but if conditions are right, much can be accomplished. Peltier once recovered 75% of lost data from a reformatted hard drive. Deleted files or formatted drives leave “shadows” of data behind, and disaster recovery specialists can sometimes retrieve this data.
If you ever need a data recovery specialist, Peltier suggests that you look for a company or individual with experience, ask for references, find out the pricing policy in advance, and look for a “no data, no charge” policy. “If somebody is charging a diagnostic fee, there is a possibility that they will tell you that they are your best shot in getting the data recovered just to get the diagnostic fee. Without a diagnostic fee, you know they are working in your best interests.”
And oh yes, did we mention do a backup?
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