| Exbioctets per second (Eio/s) | Kilobits per second (kbit/s) |
|---|---|
| 1 Exbioctet per second | 9.22337203685 × 1015 kbit/s |
| 2 Exbioctets per second | 1.84467440737 × 1016 kbit/s |
| 3 Exbioctets per second | 2.76701161106 × 1016 kbit/s |
| 4 Exbioctets per second | 3.68934881474 × 1016 kbit/s |
| 5 Exbioctets per second | 4.61168601843 × 1016 kbit/s |
| 10 Exbioctets per second | 9.22337203685 × 1016 kbit/s |
| 20 Exbioctets per second | 1.84467440737 × 1017 kbit/s |
| 25 Exbioctets per second | 2.30584300921 × 1017 kbit/s |
| 50 Exbioctets per second | 4.61168601843 × 1017 kbit/s |
| 100 Exbioctets per second | 9.22337203685 × 1017 kbit/s |
| Reference | Exbioctets per second (Eio/s) | Kilobits per second (kbit/s) |
|---|---|---|
| A dial-up modem | 6.07153 × 10-15 Eio/s | 56 kbit/s |
| Typical home broadband | 1.0842 × 10-11 Eio/s | 100000 kbit/s |
| Gigabit Ethernet | 1.0842 × 10-10 Eio/s | 1000000 kbit/s |
| Streaming a 4K film | 2.71051 × 10-12 Eio/s | 25000 kbit/s |
The exbioctet per second is a unit of data transfer rate equal to 1,024 pebioctets per second, or two to the sixtieth power octets per second. Its symbol is Eio/s. It is the binary counterpart of the exaoctet per second, and the two differ by 15.3 per cent.
No machine, network or aggregate reaches this rate. An exbioctet per second is more than eight times the total instantaneous traffic of the entire internet, and it would move the world's whole stock of stored data in a matter of minutes. The unit describes a capacity with no source that could supply it and no destination that could take it in.
Two to the sixtieth is nevertheless a familiar number in computing, because it is the size of the address space a 64-bit machine can reach in octets divided by sixteen. The same power of two turns up in filesystem limits, in memory maps and in the design of every system built on that architecture, so the quantity is well known even though no rate approaches it.
The unit exists because the IEC series was defined completely. Every binary prefix pairs with every unit, exactly as every metric prefix does, so that a reader who has never seen Eio/s can decode it from the prefix alone. A system with gaps would need a table of permitted combinations, which is precisely what a rule-based system exists to avoid.
The difference from the decimal unit is worth restating at each level because it compounds. At the kibioctet it was 2.4 per cent, here it is more than an eighth, and at the yobioctet it will be more than a fifth. That growth is the reason the binary prefixes were created, and it is why the lowercase i has to be written even in figures nobody will check.
For a converter, the treatment is mechanical: six multiplications by 1,024 from octets, or the equivalent divisions coming down. The value of doing it correctly is not that anyone will use the result, but that a tool which handles every case the same way can be trusted on the cases that matter.
One exbioctet per second equals 1,024 pebioctets per second, 1,152,921,504,606,846,976 octets per second, or about 1.153 exaoctets per second.
The kilobit per second is a unit of data transfer rate equal to one thousand bits per second. Its symbol is kbit/s, often written kbps. It was the unit of the dial-up era, and it survives today as the unit in which audio and speech encoding rates are quoted.
The dial-up sequence is worth recalling because each number marks a technical generation. Modems ran at 300 bits per second in the late 1970s, then 1,200, 2,400, 9,600, 14,400, 28,800, 33,600 and finally 56 kilobits per second at the end of the 1990s. That last figure was the ceiling of an ordinary telephone line, set by the eight-kilohertz sampling of the digital telephone network rather than by the modem.
Audio encoding is where the unit now lives. Telephone-quality speech runs at 8 to 64 kilobits per second depending on the codec, with modern low-rate codecs producing intelligible speech at 8 and high-quality voice calls at 24 to 32. Music at 128 kilobits per second was the early standard of portable players, 192 and 256 are common, and 320 is the practical ceiling of the older lossy formats.
Those numbers reward a moment of arithmetic. Music at 128 kilobits per second is 16 kilooctets per second, so a four-minute track is about 3.8 megaoctets. Uncompressed compact-disc audio runs at 1,411 kilobits per second, so the compressed file is about a tenth the size of the original, which is the whole point of the format.
Video subtitle streams, control channels and telemetry links also work in kilobits per second. So does much of the machine-to-machine traffic that fills modern networks: a sensor reporting a reading every few seconds needs a fraction of a kilobit per second, and the protocols designed for such devices are built around keeping the radio switched off most of the time.
The unit's lower-case k marks the decimal kilo, one thousand exactly. In transmission this has never been ambiguous, because network rates have always been counted in true thousands; the binary confusion that afflicts storage units does not arise here, and a kilobit per second means the same thing in every document.
One kilobit per second equals 1,000 bits per second, 125 octets per second, or about 0.9766 kibibits per second.