| Exaoctets (Eo) | Gigabits (Gbit) |
|---|---|
| 1 Exaoctet | 8000000000 Gbit |
| 2 Exaoctets | 16000000000 Gbit |
| 3 Exaoctets | 24000000000 Gbit |
| 4 Exaoctets | 32000000000 Gbit |
| 5 Exaoctets | 40000000000 Gbit |
| 10 Exaoctets | 80000000000 Gbit |
| 20 Exaoctets | 160000000000 Gbit |
| 25 Exaoctets | 200000000000 Gbit |
| 50 Exaoctets | 400000000000 Gbit |
| 100 Exaoctets | 800000000000 Gbit |
| Reference | Exaoctets (Eo) | Gigabits (Gbit) |
|---|---|---|
| A plain text message (160 characters) | 1.6 × 10-16 Eo | 0.00000128 Gbit |
| A three-minute MP3 | 3 × 10-12 Eo | 0.024 Gbit |
| A smartphone photo | 4 × 10-12 Eo | 0.032 Gbit |
| A high-definition film | 0.000000004 Eo | 32 Gbit |
| A dual-layer Blu-ray disc | 0.00000005 Eo | 400 Gbit |
The exaoctet is a unit of digital information equal to a thousand petaoctets, or a billion gigaoctets. Its symbol is Eo. It is the unit in which the world's data flows and stockpiles are counted, and it belongs to civilisations rather than to companies or machines.
The most quoted figure involving it is global internet traffic, which passed one exaoctet per month around 2004 and now runs to several hundred exaoctets monthly. Written as an annual total that is several thousand exaoctets, which is why the zettaoctet was pressed into service for yearly figures a decade ago.
A frequently repeated claim holds that all the words ever spoken by human beings would amount to about five exaoctets in text. The estimate comes from a 2003 study and is very rough, but it makes the point: five exaoctets is now less than a fortnight of internet traffic. Whatever the exact number, the flow of data through the network long ago overtook the total of everything humanity has ever said.
Storage at exaoctet scale exists only at the largest cloud providers, and even there it is spread across dozens of buildings on several continents. The annual production of all the world's hard drives and flash memory together is a few hundred exaoctets, so the exaoctet is also the natural unit for describing the output of an entire industry.
What is stored at this scale is mostly not what people imagine. Backups, replicas, logs, telemetry, machine learning training corpora and video kept for regulatory reasons dominate. Deliberately created human work — documents, photographs, recordings that someone chose to make and keep — is a small and shrinking fraction of the whole.
The prefix exa has been part of the metric system since 1975, adopted at the same conference as peta. At the time these were prefixes without applications, defined for completeness. The fact that both became working units of a commercial industry within thirty years is the clearest single measure of how quickly digital information grew.
One exaoctet equals 1,000 petaoctets, 1,000,000,000 gigaoctets, 8 exabits, or about 0.8674 exbioctets.
The gigabit is a unit of digital information equal to one thousand million bits, or one billion in the short scale. Its symbol is Gbit. It is the unit that names the current standard of wired networking, and the word gigabit has become shorthand for a particular level of capability rather than merely a quantity.
Gigabit Ethernet, standardised in 1998 and 1999, carries one gigabit per second over ordinary twisted-pair copper cabling up to a hundred metres. It replaced the hundred-megabit standard that preceded it and remains the connection built into most computers, switches and routers. That single decision fixed the meaning of gigabit for a generation of engineers.
In octets, a gigabit is 125 megaoctets. A gigabit-per-second link therefore moves about 125 megaoctets each second in ideal conditions, so a two-gigaoctet film transfers in around sixteen seconds. Real transfers are slower because protocol overhead, disc speed and the far end of the connection all impose their own limits, and it is unusual for storage to keep up with the network at these rates.
Domestic fibre services now advertise gigabit speeds routinely, and in many countries the figure has become a marketing threshold rather than a technical one. Very few households can use it: a gigabit connection is enough to stream around two hundred high-definition video services at once. Its real benefit is not peak speed but headroom, since a link that is never near capacity has consistently low latency.
Memory chips are specified in gigabits for the same reason smaller ones are specified in megabits: the count reflects the number of storage cells on the die. An 8-gigabit chip holds one gigaoctet, and eight such chips make an 8-gigaoctet memory module. Flash memory follows the same convention, so a 512-gigabit flash die holds 64 gigaoctets.
Above the gigabit the scale continues in thousands. Ten-gigabit Ethernet is standard in data centres, forty and hundred-gigabit links join buildings and cities, and the backbone of the internet runs at multiples of these. Each step keeps the same relationship to the octet, and each step is quoted in bits per second because that is what the optics and the copper actually carry.
One gigabit equals 1,000,000,000 bits, 1,000 megabits, 125 megaoctets, or about 0.9313 gibibits.