| Pebioctets per second (Pio/s) | Yottabits per second (Ybit/s) |
|---|---|
| 1 Pebioctet per second | 0.00000000900719925474 Ybit/s |
| 2 Pebioctets per second | 0.0000000180143985095 Ybit/s |
| 3 Pebioctets per second | 0.0000000270215977642 Ybit/s |
| 4 Pebioctets per second | 0.000000036028797019 Ybit/s |
| 5 Pebioctets per second | 0.0000000450359962737 Ybit/s |
| 10 Pebioctets per second | 0.0000000900719925474 Ybit/s |
| 20 Pebioctets per second | 0.000000180143985095 Ybit/s |
| 25 Pebioctets per second | 0.000000225179981369 Ybit/s |
| 50 Pebioctets per second | 0.000000450359962737 Ybit/s |
| 100 Pebioctets per second | 0.000000900719925474 Ybit/s |
| Reference | Pebioctets per second (Pio/s) | Yottabits per second (Ybit/s) |
|---|---|---|
| A dial-up modem | 6.21725 × 10-12 Pio/s | 5.6 × 10-20 Ybit/s |
| Typical home broadband | 0.0000000111022 Pio/s | 1 × 10-16 Ybit/s |
| Gigabit Ethernet | 0.000000111022 Pio/s | 1 × 10-15 Ybit/s |
| Streaming a 4K film | 0.00000000277556 Pio/s | 2.5 × 10-17 Ybit/s |
The pebioctet per second is a unit of data transfer rate equal to 1,024 tebioctets per second, or two to the fiftieth power octets per second. Its symbol is Pio/s. It is the binary counterpart of the petaoctet per second, and the two differ by 12.6 per cent.
The rate exists only as a total. The aggregate memory bandwidth of a whole supercomputer, or the summed capacity of the network fabric joining its cabinets, reaches this range, and both are sums over tens of thousands of components, each of which moves a few hundred gibioctets per second on its own.
Whether such a total means anything depends on the calculation being run. A problem that divides so that each node works mostly on its own data can use the full aggregate. A problem where every node must constantly consult every other cannot, and the machine's effective bandwidth falls to what the slowest shared path allows. Most of the art of parallel programming lies in getting problems into the first category.
In octets a pebioctet per second is 1,125,899,906,842,624, and in decimal terms about 1.126 petaoctets per second. The 12.6 per cent difference is the accumulated effect of five multiplications by 1.024, and it is now large enough that no report can leave the convention unstated without introducing real uncertainty.
The unit also appears in descriptions of parallel filesystems at the largest facilities, where a storage system spread across tens of thousands of drives delivers a few pebioctets per second to a compute cluster. That number determines how quickly the machine can checkpoint its state, which in turn determines how much work is lost when a component fails — and in a machine of that size, something is always failing.
For a converter the requirement is simply that the arithmetic be exact and the label preserved. Multiplying by 1,024 five times is not difficult; silently substituting the decimal prefix is the error to avoid.
One pebioctet per second equals 1,024 tebioctets per second, 1,125,899,906,842,624 octets per second, or about 1.126 petaoctets per second.
The yottabit per second is a unit of data transfer rate equal to a thousand zettabits per second. Its symbol is Ybit/s. For thirty years it was the largest rate the metric system could name, and it describes a speed that has no application anywhere: not in engineering, not in research, and not in any forecast that anyone takes seriously.
Its distance from reality is easy to state. Global internet traffic averages roughly one exabit per second, so a yottabit per second is about a million times the combined communication of the entire human species. The largest single link ever built runs at a few hundred terabits per second, which is a ten-billionth of this figure.
The unit is nonetheless properly defined, and that completeness is the point. The metric system's rule is that every prefix combines with every unit without exception, so a reader who has never seen Ybit/s can decode it from the prefix alone. A system with gaps would need a table of which combinations are legal, and a table is exactly what a rule-based system exists to avoid.
There is a physical way to think about the number. A yottabit per second is 125 zettaoctets per second, and the total quantity of data humanity has ever stored is a few hundred zettaoctets. A link at this rate would therefore transmit the entire accumulated information of the species in a couple of seconds. No such body of data exists in one place to be sent, and nothing at the far end could receive it.
The prefix yotta was adopted in 1991 alongside zetta, at a conference that also had to consider which letters remained free. It stood at the top of the metric ladder until 2022, when ronna and quetta were added above it, partly because data quantities were beginning to approach the old ceiling. Rates have not followed quantities upward at the same pace.
For a converter, handling the unit is a matter of consistency rather than utility. A tool that converts every metric prefix correctly does not need to decide which of them anyone will use, and a figure written in yottabits per second — however unlikely — converts by the same rule as any other.
One yottabit per second equals 1,000 zettabits per second, 125 zettaoctets per second, or about 0.8272 yobibits per second.