Exabyte – one trillion bytes

What’s the actual size of an exabyte? Data volumes and storage capacities are an integral part of 21st century technologies. But while computer users measure storage capacities for photos, texts, and videos in gigabytes and terabytes, technology giants like Google and Tesla are already dealing in units of exabyte. When you’re scrolling through social networks, you may be able to imagine the huge number of terabytes of images and videos that accumulate on the servers of social media giants. And that’s only a fraction of the global data quantities measured in exabytes on a monthly basis.

Units of information are a bit like dress sizes – at least to a certain degree. But data volumes have little intention of shrinking. When IBM published the first hard disk drive with the IBM 305 RAMAC in 1956, it came with a storage capacity of just 3.75 megabytes. Nowadays, this would equate to a single photo with a resolution of 12 megapixels.

Globally, we now generate multiple exabytes of data monthly. Google alone claims to store several exabytes worth of data. The exabyte is a unit of information that’s still restricted to global data volumes and storage quantities in data centres; it’s not a measure of our commercially available hardware like the external storage hard drives we may use daily. In other words, it’s a measure of big data.

One byte is the smallest quantity of data and consists of 8 bits. This means that a bit is the smallest unit of information. So, everything is based on bits and bytes. One bit, abbreviated from binary information digit, can represent one of two states: 1 or 0. Since computers process information via the binary code, this is the smallest understandable piece of information in the IT sector.

In information processing, one bit is too small to transmit or store complex information. One byte is therefore the smallest amount of data and serves as the basis for all storage capacities. In contrast to the bit, one byte can assume 2⁸ (256 bits) different states. At least one byte is required to represent a letter or an alpha-numeric character.

According to the decimal system, an exabyte comprises 10¹⁸, i.e., one trillion bytes. A megabyte is made up of one million bytes. As a reminder: around 4 megabytes are required today to save a high-resolution photo. The current largest unit of information is the zettabyte, which, according to the binary system, corresponds to 1,024 exabytes. Anyone who owns an external hard drive in the terabyte range may be able to imagine what that means: 1,024 terabytes are 1 petabyte, 1,024 petabytes make 1 exabyte.

Units to measure memory size typically come in two standards: binary and decimal. The binary standard is recommended by the IEC (International Electrotechnical Commission) because it maps storage capacities more precisely and is better suited to data carriers. The decimal prefix is based on the SI (‘International System of Units’) and is more common, but reflects rounded, less precise data quantities. Where it gets confusing is that decimal prefixes are also being used for binary quantities. So far, however, binary prefixes have failed to become more established.

Here are the eight official units of measurement for byte powers: