| Petaoctets per second (Po/s) | Zebibits per second (Zibit/s) |
|---|---|
| 1 Petaoctet per second | 0.00000677626357803 Zibit/s |
| 2 Petaoctets per second | 0.0000135525271561 Zibit/s |
| 3 Petaoctets per second | 0.0000203287907341 Zibit/s |
| 4 Petaoctets per second | 0.0000271050543121 Zibit/s |
| 5 Petaoctets per second | 0.0000338813178902 Zibit/s |
| 10 Petaoctets per second | 0.0000677626357803 Zibit/s |
| 20 Petaoctets per second | 0.000135525271561 Zibit/s |
| 25 Petaoctets per second | 0.000169406589451 Zibit/s |
| 50 Petaoctets per second | 0.000338813178902 Zibit/s |
| 100 Petaoctets per second | 0.000677626357803 Zibit/s |
| Reference | Petaoctets per second (Po/s) | Zebibits per second (Zibit/s) |
|---|---|---|
| A dial-up modem | 7 × 10-12 Po/s | 4.74338 × 10-17 Zibit/s |
| Typical home broadband | 0.0000000125 Po/s | 8.47033 × 10-14 Zibit/s |
| Gigabit Ethernet | 0.000000125 Po/s | 8.47033 × 10-13 Zibit/s |
| Streaming a 4K film | 0.000000003125 Po/s | 2.11758 × 10-14 Zibit/s |
The petaoctet per second is a unit of data transfer rate equal to a thousand teraoctets per second, or eight petabits per second. Its symbol is Po/s. It describes the total internal bandwidth of the largest computing machines rather than any single connection, and it exists as an aggregate rather than as a rate anything can sustain on its own.
The clearest case is the interconnect of an exascale supercomputer. Such a machine has tens of thousands of nodes, each linked to the network at hundreds of gigaoctets per second, and the sum across the whole fabric reaches petaoctets per second. That figure is the reason such machines can run a single calculation spread over the whole system rather than many small independent ones.
Memory bandwidth adds up the same way. A machine with ten thousand accelerators, each with several teraoctets per second of local memory bandwidth, has tens of petaoctets per second in total. Whether that total means anything depends entirely on the calculation: a problem that can be divided so each node works mostly on its own data can use it, and a problem that cannot, cannot.
Data centre networks reach this range too. The aggregate capacity of the switching fabric inside a very large facility, counting every link between every rack, is measured in petaoctets per second. The design goal is that any server can reach any other at close to full speed, which requires far more internal capacity than the facility's external connections.
For scale, a petaoctet per second would transfer the entire contents of a large national archive in a second, or fill every hard drive manufactured in a day within about a minute. No storage system can supply data at this rate, and none can absorb it; the number describes movement inside a machine, between memory and processors, where nothing is being stored at all.
The unit also serves in optical research, where a single fibre carrying a petabit per second is 125 teraoctets per second, and an experimental system aggregating several such fibres approaches the petaoctet. Those figures come from laboratories rather than from anything deployed.
One petaoctet per second equals 1,000 teraoctets per second, 8 petabits per second, or about 0.8882 pebioctets per second.
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.