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Petabyte, Exabyte, Zettabyte, Yottabyte - just how big are they?

The spindle and read arm of a mechanical hard drive
(Image credit: Pixabay)

When you're in the market for a new home computer, there are some specifications you consider more than others. Typically, you look at the processor speed, the amount of memory and the hard drive size, factoring in whether that's a speedy SSD or slower spinning hard drive. You may also consider picking up one of the best external hard drives for even more storage.

As you've become more familiar with computing terms, you instinctively know whether a hard drive is a decent size or not. Beyond the well-known megabyte, gigabyte and terabyte there are larger classifications of data storage capacity. To fully understand the scale, follow the example of an MP3.

Most people are aware that an MP3 is going to be about 1MB per minute of an audio track, give or take. So, a typical three-minute song is going to take up about 3MB of space. As technology improves, you're able to purchase larger hard drives so you can store more files or install bigger programs.

Back in 1983, the biggest hard drives stored about 10MB of data. Today, that translates into about two and a half MP3s. In 1991, a computer could come with a one-gigabyte hard drive, which is about 1,024MB – or about 341 three-minute MP3s. Computers use binary rather than base-10 to count with, which means using powers of two. 1,000 isn't a power of two, and 1,024 is the nearest.

Once technology reached the 2000s and beyond, hard drive space increased exponentially. It isn't uncommon to find a computer with a 2TB hard drive now at a reasonable price. A single terabyte is the equivalent of 1,024GB, or about 342,000 three-minute MP3s.

Now we get into the bigger bytes. Next up is the petabyte. This equals 1,024TB, so that means you could store about 341 million three-minute MP3s. If you want an even larger measurement of data storage, there's the exabyte, which is 1,000 times larger than a petabyte. So, a hard drive that's 1EB can store 341 billion three-minute MP3s – that's a lot of music. Then you get to the zettabyte, which is 1,000 times larger than an exabyte, which is 1 million petabytes. You could never listen to them all, but if you had a 1ZB hard drive, you could store more than 34 trillion three-minute songs.

As unbelievable as it seems, there's an even larger measurement of data: the yottabyte. It's about 1,000,000,000,000,000,000,000,000 bytes, or 1 septillion bytes. It's a bit difficult to comprehend at this point, but you would need a hard drive that costs about $100 trillion.

One of the best ways to visualize this data was developed by Wikibon. Imagine one of best tablets with 32GB of storage that's fully loaded. A single petabyte would equal about 31,250 of those. Now stack those tablets on top of each other and compare them to some of the world's tallest buildings. The Empire State building stands at 1,250 feet. Those tablets stack up to twice that height at 2,604 feet – almost as tall as the Burj Khalifa, the world's tallest building. The estimated amount of data in the digital world in 2010 was 1.2ZB, or 37 billion fully loaded tablets.

Although we're a long way off from purchasing home computers with internal storage of 1ZB, some of these larger data storage measurements aren't out of the question. In time, and with increased technology, we may see hard drives as big as 1PB, but for now, a hard drive with 10TB is considered hefty – and pricey.