Did you know that your hard drive is divided into ‘sectors’ and data is assigned to specific sectors when it is stored? That is why when you have ‘bad’ sectors your data can become corrupted and may be inaccessible or not displayed correctly.
The most important thing that you need to understand about bad sectors is that they come in two distinct types: Physical and logical.
Physical Bad Sectors
A physical bad sector is a sector of storage on your hard drive that has been physically damaged for some reason or other. The most common causes of physical bad sectors is when the hard drive head comes into contact with the plate and damages it, or when dust manages to get through the air filter and settles on the plate and damages it.
Regardless of the cause however, the one thing that you need to know about physical bad sectors is that you can’t repair them. If your hard drive is starting to develop more and more physical bad sectors it is likely that it is about to fail and so the best thing you can do is backup all the data that is on it and replace the hard drive.
Logical Bad Sectors
In contrast to physical bad sectors, logical bad sectors are sectors that simply aren’t working properly. Normally it is caused by software issues, such as an interrupted write process on the hard drive due to a sudden power outage, or damage due to viruses and certain types of malware.
Unlike physical bad sectors, if you have logical bad sectors you may be able to repair them using a disk check tool (such as chkdsk on Windows). The tool will be able to scan your hard drive for bad sectors and identify whether they are repairable or not, then overwrite the data on them so that they can be used.
Because it is so easy to repair logical bad sectors, as a rule of thumb if you have any bad sectors it is always best to use a disk check tool initially. That way you’ll be able to repair logical bad sectors, and identify unrepairable physical bad sectors. In short it can both diagnose and repair the problem.
While a few individual bad sectors should not be cause for concern, if you notice that your hard drive has lots of bad sectors or is starting to develop more and more bad sectors continuously – its lifespan is probably drawing to an end. Rather than waiting for it to fail, you should take preemptive measures to backup data so that you don’t end up losing it all.
Once a hard drive does actually fail, recovering data can be much more difficult. In some cases you may need to actually repair a hard drive or get professional help in order to access the data and recover it. Naturally this isn’t ideal, which is why it is better to take steps beforehand instead.