Some forms of data loss have nothing to do with faults in the drive hardware itself. These are often called “logical” forms of data loss because the problem happens at the software/data logic level- the hardware itself is fine, the problem is a logical (software) one caused by a mistake you or your computer made. For example, if you delete an important file… then realise you shouldn’t have done that. Bad news, but the drive did exactly what it was told to do.
Sometimes the fault can be blamed on the computer-maintained “filesystem” becoming corrupt and losing files.
Think of it this way- the hard drive is like the shelves that books in a library are stored on. If the librarian messes up his or her catalogue and some books get wrongly thrown out or misplaced because of this… it’s not the fault of the shelves. (That’s not a perfect analogy, but it’s along those lines!)
Don’t Blame the Drive?
At heart, most drives are simply devices that provide a very large number of “sectors” for data storage. Each sector holds a fixed amount of data, has its own identifier and is individually accessible… but that’s it.
The drive itself doesn’t “know” anything about “files” and “folders”, however. All that is controlled by your computer, where it decides (say) that certain sectors are allocated for catalogue data, file pointers and other uses, and other sectors are for data. As far as the drive’s concerned though, the computer’s asking it to read and write raw sector data- it’s the computer that keeps track of what this actually means and what “files” are there.
So, if (for whatever reason) corrupt data is written to the catalogue- either because of a software bug, or because the drive- or memory card- was removed, or the power was disconnnected in the middle of the process… the drive isn’t to blame, but you still have a serious problem.
In fact, faulty or corrupt (i.e. misleading) catalogue information can cause further corruption as catalogue or file sectors get overwritten when they shouldn’t be. That’s why you should stop using such drives as soon as you become aware of the problem.
Data lost in this way- if retrievable- usually doesn’t require hardware modification or repair to recover, although it can still take a lot of work and skill to get it right. (Incorrect use of software can, however, still increase the software damage and reduce further the chances of recovery. This is why we don’t recommend it unless you really know what you’re doing).
The one silver lining here is that- provided it’s clear that the drive itself wasn’t at fault- it can normally be safely reused.
