It stores all your word documents, programs, games, music and videos, yet most of the time, you pay it no mind. Hard drives are wonders of engineering, a product of hours of hard work and pushing physical limits to attain the data storage we need in our lives. It’s hard to grasp how important it is until it up and quits on you, taking your data and your work with it.

But how exactly does a hard drive work? There are two major parts of the hard drive – the platter and the read/write head.

The disk platter home to a trillion small magnets and each magnet has two polarities. The read/write head is like a record tone arm, and has the ability to switch the polarity of the small magnets when it’s writing data, and read the polarity when it’s reading data.

When the disk platter spins, the read/write head moves back and forth at up to 10 meters/second and must stop on a line 1/10 the width of a human hair to be able to correctly read the polarity of each magnet. After that, the data then goes into the circuitry of the drive, to your computer.

There are two basic sizes for consumer drives: 2.5-inches for notebook and portable devices, and 3.5-inches for desktop applications. The sizes are a reference to the size of the disk platter used, not the physical size of the entire drive.

The smaller 2.5-inch drives are slower and have less data throughput than the bigger sized drive, but consume less power and are more tolerant to being moved around ideal for mobile environments.

The bigger 3.5-inch drive on the other hand consumes more power, is physically bigger than the 2.5-inch drive but is cheaper per gigabyte and can achieve speeds up to 15,000 RPM, with entry level drives clocking in at 7200 RPM, compared to 5400 RPM in 2.5-inch drives.

There is also a new type of drive that’s slowly gaining ground, and that is SSDs, or solid state drives. Basically thumb drives on steroids, SSDs are extremely quick, small, has no moving parts, consume less power and are, in theory, more reliable than traditional drives.

Unfortunately, they are also extremely expensive, and are limited in their capacity.

Speaking of capacities, it’s not uncommon to see hard drives packing 1TB worth of storage today. Of course that begs that question: is it better to spread out data in separate, smaller drives, or consolidate it into one big drive?

While it does seem logical, it’s not worth it, especially when you consider the price and power requirements of two 500GB hard drives surpass a 1TB drive.

Better to religiously back-up important data than to splurge on multiple drives, as it’s something you should be doing, small hard drive or no.