Life and Death of Storage Devices 3: Mechanical Hard Disks

Mechanical hard drives have been inside computers for a very long time, perhaps since the late 1980s. Like floppy disks, they rely on magnetic technology to store data on discs but the technology had become so advanced and sensitive that they switched from plastic to metal and needed to put the discs in a very closed box.

The factories that make hard drives have no dust in them. The air processors remove it so that the magnetic particles in the dust doesn’t interfere with the magnetic particles in your drive. Before the hard drive leaves the factory they seal it making it impossible for dust to get inside but also impossible to repair.

Open Hard Disk platter

In all mechanical devices (as we saw with the failure of CD-ROM drives in part 1), there are parts that wear down from use or from a bad environment. For a hard drive the worst environment seems to be poor voltage control but temperature & handling also play roles. The motors in hard drives, especially laptop hard drives seem especially sensitive to input voltage fluctuations, or changes, from 230V.

In a hard drive there are motors which spin the discs, there are motors which move the read/write magnet arm and there are micro processors, chips which control the operations. If any of these are damaged, they are nearly impossible to fix. Umeme uchafu is probably the most common way for hard drives to die in Tanzania. A spike might kill the chips and  inconsistent voltage might wear down one or both of the very accurate motors.

If a laptop drive (2.5″) is dropped while it is running, the magnetic arm will crash into the discs causing a small dent or permanent destruction. If they’re dropped when turned off they’re impressively tolerant. Desktop sized (3.5″) hard drives are even more sensitive to being dropped, even when turned off.
Voltage Regulator, useful for laptops

Hard drive deaths are mysterious. Google has millions of hard drives in its facilities and it has published papers on the strange and random ways they fail. There are very few definite patterns, especially here in Africa. Even in a perfect environment with air conditioners, perfect power and care when handling they can fail. The most important things are to be preventative by using power cleaning devices and keeping backups.

One pattern which is worth noting is that once hard drives have lived past 1yr of consistent use they’re likely to continue to last, provided good voltage, handling.

In my opinion, you should get a voltage regulator to protect from inconsistent voltage on laptops and some form of AVS for a desktop. Keep in mind a voltage regulator will not protect from very big spikes or surges such as transformer explosions. At our TTC we have seen UPSs behind voltage regulators die even after the fuse has burnt.

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