| Zebibits per second (Zibit/s) | Petabits per second (Pbit/s) |
|---|---|
| 1 Zebibit per second | 1180591.62072 Pbit/s |
| 2 Zebibits per second | 2361183.24143 Pbit/s |
| 3 Zebibits per second | 3541774.86215 Pbit/s |
| 4 Zebibits per second | 4722366.48287 Pbit/s |
| 5 Zebibits per second | 5902958.10359 Pbit/s |
| 10 Zebibits per second | 11805916.2072 Pbit/s |
| 20 Zebibits per second | 23611832.4143 Pbit/s |
| 25 Zebibits per second | 29514790.5179 Pbit/s |
| 50 Zebibits per second | 59029581.0359 Pbit/s |
| 100 Zebibits per second | 118059162.072 Pbit/s |
| Reference | Zebibits per second (Zibit/s) | Petabits per second (Pbit/s) |
|---|---|---|
| A dial-up modem | 4.74338 × 10-17 Zibit/s | 5.6 × 10-11 Pbit/s |
| Typical home broadband | 8.47033 × 10-14 Zibit/s | 0.0000001 Pbit/s |
| Gigabit Ethernet | 8.47033 × 10-13 Zibit/s | 0.000001 Pbit/s |
| Streaming a 4K film | 2.11758 × 10-14 Zibit/s | 0.000000025 Pbit/s |
The zebibit per second is a unit of data transfer rate equal to two to the seventieth power bits per second, which is 1,024 exbibits per second. Its symbol is Zibit/s. It is the binary counterpart of the zettabit per second, and the two differ by 18.1 per cent — approaching a fifth.
Nothing runs at this rate, and nothing is designed to. A zebibit per second is about a thousand times the total instantaneous traffic of the internet, and it would move the world's entire stock of stored data in a matter of minutes. The unit exists because the IEC series, like the metric series it parallels, was defined completely rather than only as far as anyone then needed.
That completeness is a deliberate design principle rather than an oversight. A measurement system whose names run out at some arbitrary point forces every future user to improvise an extension, and improvised extensions conflict with one another. Defining the whole ladder in advance costs nothing and removes the possibility.
The eighteen per cent gap at this level is the clearest illustration of why the binary series was needed at all. At the kibibit the two conventions differed by 2.4 per cent, which nobody noticed; the discrepancy multiplies by 1.024 at each step, and by here it is large enough that no reader could treat the two labels as interchangeable even in casual writing.
In octets a zebibit per second is 147,573,952,589,676,412,928, or 128 exbioctets per second. Expressing the same rate in every unit on the scale is an exercise rather than an application, but it is one a converter has to perform correctly, because the arithmetic does not become approximate when the quantity becomes unreachable.
The practical lesson is the one the whole binary series teaches: the lowercase i is not optional. It is the only mark in a written figure that distinguishes a power of two from a power of ten, and by this point in the scale the two are nearly a fifth apart.
One zebibit per second equals 1,024 exbibits per second, 147,573,952,589,676,412,928 octets per second, or about 1.181 zettabits per second.
The petabit per second is a unit of data transfer rate equal to a thousand terabits per second. Its symbol is Pbit/s. It marks the frontier of optical transmission research: the rate at which laboratories have carried data down a single strand of glass, and which no deployed system yet approaches.
The records were set by combining three techniques. Multi-core fibre puts several separate light-guiding paths inside one cladding, so that a single strand behaves like a bundle. Wavelength division multiplexing runs hundreds of distinct colours down each of those cores. Advanced modulation encodes many bits into each pulse. Multiplying the three together is what reaches a petabit per second.
Such demonstrations run over tens of kilometres of fibre in controlled conditions, not the thousands of kilometres a working sea cable must span. Distance is the hard part: signals attenuate, dispersion smears pulses together, and non-linear effects in the glass grow with power. Every kilometre added makes the same rate harder to sustain, which is why deployed cables sit two orders of magnitude below the laboratory record.
In octets a petabit per second is 125 teraoctets per second, which is roughly the storage of a hundred and twenty-five large hard drives moved every second. Nothing at either end of such a link could produce or absorb data at that rate; the figure describes the medium's capacity rather than any use of it.
At the network level the unit is used for aggregates. The total interconnect capacity of a very large data centre, the summed capacity of all the cables landing on a continent, and the peak traffic of the largest content networks are quoted in petabits per second. These are sums over thousands of links, not the rating of any one.
The trajectory is worth noting. Transoceanic capacity has grown by roughly a factor of ten every seven or eight years for several decades, driven almost entirely by better electronics and better coding rather than by more glass. If that continues, the petabit per second will describe a working cable within a generation.
One petabit per second equals 1,000 terabits per second, 125 teraoctets per second, or about 0.8882 pebibits per second.