Petabyte – what is it?

Up until the turn of the mil­len­ni­um, the floppy disk drive was standard computer storage device. The disk had a storage capacity of less than 3 megabytes (MB) but that was a large amount of data in the late 1990s. Today, 3MB is hardly enough to back up a single photo.

It’s now common for computer users to save a multiple of that quantity of data onto their computers, smart­phones, external hard drives, USB sticks, or cloud providers online. The capacity of these storage media often exceeds 1,000 MB. But to keep in­creas­ing quant­it­ies of data legible, units of in­form­a­tion are required that denote larger quant­it­ies in simple figures. Petabytes are already being used by main­frames and server centres to denote their capacity and sooner or later it’s expected that they’ll reflect the capacity of common storage media.

A byte refers to a quantity of data. However, the modern USB stick, computer, or other data carrier offers ca­pa­cit­ies well beyond 1,000 bytes. Therefore, in­form­a­tion units that are multiples of a byte are in use. Gigabytes and terabytes are common measures of memory for data storage capacity. In the case of server centres and main­frames, the amount of data well exceeds that of private storage devices which is where petabytes come in. There are 1,024 terabytes in one petabyte.

Given rapid di­git­al­isa­tion, the in­creas­ing pop­ular­ity of streaming services and continued tech­no­lo­gic­al de­vel­op­ments, it’s only a matter of time before petabytes will become more relevant to the average user. There’s already a growing demand for larger storage ca­pa­cit­ies and data carriers continue to scale their volumes. An SSD in 2.5-inch format now stores up to 15 terabytes. For 1 petabyte of in­form­a­tion, around 68 SSDs are required.

A single letter makes all the dif­fer­ence. Take internet providers who advertise their services with ‘up to 100 Mbit/s’ (which trans­lates to 0.0125 GB/s) while a hard drive may be described as offering 512 gigabytes of storage space. Similarly, the unit petabyte can be dis­tin­guished from petabits. But what’s behind these near identical terms?

A bit can adopt one of two states: ‘1’ denotes ‘on’, ‘0’ stands for ‘off’. This binary system cor­res­ponds to the smallest unit of in­form­a­tion in a computer. To represent a character that is readable by humans, 256 (2⁸) possible states are necessary. Therefore 8 bits are combined to 1 byte. In practice, bytes are used to specify memory capacity and bits for data con­sump­tion and trans­mis­sion speeds.

The term ‘petabyte’ denotes vast amounts of data, but we rarely encounter these in our daily life. When spe­cify­ing the storage capacity of hard disks or other data carriers, megabytes, gigabytes, and terabytes are commonly used. The con­ver­sion factor between two con­sec­ut­ive quant­it­ies is always 1,024 (2¹⁰). The des­ig­na­tion according to the decimal system is therefore mis­lead­ing; in fact, it is a common com­bin­a­tion of decimal prefixes and binary numbers.

The following table is an overview of the con­ver­sion from petabytes to all common units of in­form­a­tion:

It didn’t take long to come up with the term ‘petabyte’. As with megabytes, kilobytes, and gigabytes, the prefix is derived from the Greek. One petabyte currently comprises vast amounts of data found on main­frames and server centres. Since it’s widely spec­u­lated that the amount of data will continue to grow, these larger units will become in­creas­ingly important.