Sunday night, tomorrow you have an important presentation to deliver or assignment, then without any warning of any kind your screen freezes, you reboot the system after no response from the keyboard or mouse.



No problem the file will be auto saved, hang, what's this message hard disk drive (HDD) not detected ?! gulp, I'll try a reboot, same error!

This kind of scenario can make any IT battle hardened user fold on the spot, but it need not be this way.

The bad news

All hard drives have finite lives and MTBF (Mean Time Between Failure) as many other products, however HDD will fail when you least expect it or when it hurts most.

Magnetic storage media aka HDD are electro, mechanical devices which operate at the envelope of mechanical tolerances. What do we mean by this ? Well modern hard drives spin platters at speeds from 4200 to 15K which are either metal or glass and covered by a process called spluttering a magnetic sensitive material, now the part which decodes and encodes data directly to the platters are part of the head stack assembly, now the tolerance bit, these heads have to repeat ably go to specific locations on the media quickly (less than 10MS), here is where issues can really happen. The heads "fly" above the platters and contrary to popular belief the disk enclosure is not a vacuum, or how could the heads "fly" above the surface?

Now, due to heat, vibration, shock or system malfunction the head stack assembly may place the heads directly on the surface in a inappropriate place and way, thus damaging the surface; you have what most people would call a head crash.

The heat is on

Ok, so heat really can cause issues for your hard drive and here is why. Excessive heat to the media can cause the thermal expansion to the head stack assembly, thus "shifting" the precise alignment. Magnetic properties also change with thermal variations, and finally the PCB (printed circuit board) can enter a thermal runaway scenario; The motor control chip gets warm, the ambient and working temperature of the drive increases, this affects the resistance to failure which is often the main failure type of PCB failure.

UPS, UPS and away

Finally power cycling of hard drive media can cause catastrophic failure along with excess power and brownouts. Typically this type of failure causes clicking or noisy media.

The good news

Most of the above issues can very easily be avoided with such items as hard drive cooling kits, these supply cool air directly to the hard drive enclosure and PCB.

UPS (Uninterruptible power supply) for power cycling can also be implemented to ensure smooth supply of electricity.

Logical issues to file systems can be rectified via a little house maintenance regularly implemented such as virus, spyware / malware, root kit updates and scans, and defragmentation if your file system or 3rd party software supports this.

Finally, not all hard drives are equal, research has shown that the reliability varies greatly from manufacturer to manufacturer choose your drives wisely.