Lost Data

“If your hard drive is making unusual noises TURN IT OFF IMMEDIATELY. This symptom can indicate a catastrophic failure or a head crash and could destroy your data. The noise your are hearing is generally the head stack (the read/write heads) in the hard disk drive trying to find data in a location on one of the platters it needs to start the drive. Any attempt at recovering these drives yourself may cause further damage or permanent data loss. But, this symptom is not always caused by the heads failing. There is other code called “firmware” in the drive that may be corrupt and causing the same action by the heads. This can only be diagnosed by a trained professional. Be aware Do It Yourselfers, because this firmware is unique to that hard drive, swapping the hard drives PCB could make the drive unrecoverable.”
- datarecovery.co.ke

“Myth: I can recover the data myself
Fact: Do it yourself (DIY) projects can work especially if the hard drive has a logical failure of the file system. We however do not recommend this for Some reasons include like :The media has physical problems and running the software against the media made things worse; or, the software was run against the media and the recovered data was written back to the same media effectively destroying the data. Before you consider a DIY data recovery project call us for advice.”
- http://datarecovery.co.ke/myths-and-facts-about-data-recovery/

“A typical HDD design consists of a spindle that holds flat circular disks, also called platters, which hold the recorded data. The platters are made from a non-magnetic material, usually aluminum alloy, glass, or ceramic, and are coated with a shallow layer of magnetic material typically 10–20 nm in depth, with an outer layer of carbon for protection.”
- escotal.com

“The first step in recovering from a data loss is to ascertain whether the loss is a result of a physical hard drive failure, i.e. broken hardware; or, a logical drive failure, i.e. corruption or loss of File System or data.“
- getdata.com

“Traditional Hard Disk Drives (HDDs) use a spinning magnetic platter and a read/write arm that floats over the platter (kind of like a record player) and have various mechanical components that can fail. However, from a data recovery standpoint, the success rate for recovering data from failed HDDs is significantly higher than SSDs or Solid State Drives.”
- Ken Colburn

A hard drive is like a scale. It doesn’t know the difference between things that are on it; it only knows their size. But instead of kilograms, a hard drive measures things in terms of megabytes (MB), gigabytes (GB) and terabytes (TB.)