Physical Media Damage and Types of Hard Drive Crashes
Have you ever had a hard drive fall from your desk? Or had one experience a fire (and ensuing water from the sprinklers)? These and many other types of damages that a hard drive can experience are physical media damage (PMD) and, believe it or not, your data may survive it. In this post we’ll get to know the technical terms as well as the different stages of data loss and whether data is still (hopefully) recoverable after a ‘near-death’ experience.
What is Physical Media Damage?
Physical media damage is damage that occurs when the magnetic coating on hard drive platters experience disruption. PMD can occur in any storage device which has mechanical moving parts. Our engineers see PMD in CD's, DVD's, ZIP disks, floppy disks and tapes. Basically, PMD refers to any damage to the data storage media.
What causes Physical Media Damage?
PMD most commonly occurs when the read/write heads come in to contact with the spinning platters. This may be as a result of the drive dropping while in operation. Over-use and overheating can also be contributing factors. Platters can also experience damage if the internal chamber becomes contaminated. Any substance that infiltrates the hard drive case can potentially cause a 'crash' if it settles between the heads and the platter.
How to identify physical damage to a hard drive?
There are warning signs that can help you identify physical damage, these may include:
- Computer failing to start up or not operating correctly - sluggish when opening files; displaying data access errors or locking up system with errors
- A clicking noise when the drive is being accessed, a common pattern is click-pause-click-pause-click, followed by the drive stopping and the sound of it spinning again
- The drive remains silent (no spin-up sound, no movement/vibration felt) when powered up
If a hard drive crashes, is the data recoverable?
This is a question our clean-room engineers are asked all the time. The answer is it depends on the make of the drive, and the severity of the crash. The best way to look at this is to try and understand different types of crashes. At Ontrack, we split the severity of the damage in to three main categories:
Crash Level 1 (C1)
Most of the time these are very minor crashes that can barely be seen with the naked eye. However, if these crashes lie within the system area then it may prevent the drive from coming ready and being accessible. This means that occasionally a C1 can still be unrecoverable.
Crash Level 2 (C2)
A C2 crash is immediately visible, and depending on the drive it can be unrecoverable. However, it is still possible to image* drives even when the damage is extensive.
*The imaging process involves the work of experienced lab engineers who will "image" the drive sector by sector, reconstruct the operating system file structure rebuilding the links to the file data and perform an extraction of data to an external storage.
Crash Level 3 (C3)
This is the end of the road as far as data recovery is concerned. A C3-level crash means all the magnetic coating has been scratched off the platters. Hence, there is no more data present so the drive is unrecoverable.
What to do next?
If you suspect your media has suffered physical damage, turn it off immediately to avoid further damage to the platters which could result in irreversible data loss.
Do not try this at home!
We see many drives that have been opened before they were sent to us, but even the slightest scratch or small dent in the platter can cause an alignment problem. Unknowingly, people are destroying their chances to recover their data!
Our advice is to never open the drives (or indeed any media) prior to sending it to an expert data recovery company. Unfortunately, with physical data losses there is no option for a DIY - a sterile environment and professional help are necessary to try to get your data safely back to you.