| Yobioctets per second (Yio/s) | Zebioctets per second (Zio/s) |
|---|---|
| 1 Yobioctet per second | 1024 Zio/s |
| 2 Yobioctets per second | 2048 Zio/s |
| 3 Yobioctets per second | 3072 Zio/s |
| 4 Yobioctets per second | 4096 Zio/s |
| 5 Yobioctets per second | 5120 Zio/s |
| 10 Yobioctets per second | 10240 Zio/s |
| 20 Yobioctets per second | 20480 Zio/s |
| 25 Yobioctets per second | 25600 Zio/s |
| 50 Yobioctets per second | 51200 Zio/s |
| 100 Yobioctets per second | 102400 Zio/s |
| Reference | Yobioctets per second (Yio/s) | Zebioctets per second (Zio/s) |
|---|---|---|
| A dial-up modem | 5.79026 × 10-21 Yio/s | 5.92923 × 10-18 Zio/s |
| Typical home broadband | 1.03398 × 10-17 Yio/s | 1.05879 × 10-14 Zio/s |
| Gigabit Ethernet | 1.03398 × 10-16 Yio/s | 1.05879 × 10-13 Zio/s |
| Streaming a 4K film | 2.58494 × 10-18 Yio/s | 2.64698 × 10-15 Zio/s |
The yobioctet per second is a unit of data transfer rate equal to 1,024 zebioctets per second, or two to the eightieth power octets per second. Its symbol is Yio/s. It is the largest binary rate the International Electrotechnical Commission has named, and the last rung of the ladder that began with the bit per second.
At this final step the binary and decimal conventions differ by 20.9 per cent. That figure closes the argument the IEC prefixes were created to settle: a naming habit that was 2.4 per cent wrong at the kibibit per second has grown, through eight successive multiplications by 1.024, into a discrepancy of more than a fifth. No system of measurement can carry an ambiguity that large, and the whole binary series exists to remove it.
The rate itself has no referent. A yobioctet per second is more than eight million times the total instantaneous traffic of the internet, and it would transfer everything humanity has ever stored several thousand times over in a second. Nothing produces data at that rate, nothing consumes it, and nothing is designed with it in view.
That does not make the unit pointless. Defining the whole ladder in advance means that the rule — every prefix combines with every unit — is all anyone has to learn, and a rule is easier to carry than a table of exceptions. The same principle gave the metric system its complete prefix set, and the addition of ronna and quetta in 2022 extended the decimal side without any matching binary names being defined.
The practical value of a unit like this is that it makes a converter's behaviour uniform. A tool that handles the impossible cases by the same rule as the ordinary ones can be trusted not to have special cases hidden in it, and that is a property worth having in something whose whole purpose is to be relied upon.
For the reader, the whole series comes down to one character: Kio/s, Mio/s, Gio/s, Tio/s, Pio/s, Eio/s, Zio/s and Yio/s are binary; ko/s, Mo/s, Go/s, To/s, Po/s, Eo/s, Zo/s and Yo/s are decimal; and the difference between them widens from a rounding error to a fifth as you climb.
One yobioctet per second equals 1,024 zebioctets per second, 1,208,925,819,614,629,174,706,176 octets per second, or about 1.209 yottaoctets per second.
The zebioctet per second is a unit of data transfer rate equal to 1,024 exbioctets per second, or two to the seventieth power octets per second. Its symbol is Zio/s. It is the binary counterpart of the zettaoctet per second, and the two differ by 18.1 per cent.
A link running at this rate would transfer everything humanity has ever stored several times over in a single second. That is the plainest way to describe how far it lies beyond anything that exists, is planned, or has been seriously proposed. The unit is a name for a quantity, not a description of a thing.
It is worth being precise about why such names are still defined. A measurement system is a set of rules, and the value of a rule is that it applies without exception. The moment a system says that certain prefix-and-unit combinations are legal and others are not, every user must carry a table instead of a rule, and different users will carry different tables. Complete definition is cheaper and safer.
The physical obstacles are not merely large but qualitative. At a zebioctet per second, the energy needed to switch the required number of states, even at the thermodynamic minimum, becomes a substantial power; the practical figure for real electronics is many orders of magnitude above that; and the number of parallel channels required exceeds anything that could be built and cooled. These are not engineering targets.
The 18.1 per cent gap from the decimal unit continues the pattern that runs through the whole binary series. Each step multiplies the discrepancy by 1.024, so a convention that was harmless at the kibioctet has become, by this point, a difference no reader could overlook. Making that visible is the purpose the IEC prefixes serve.
In practice, a converter meets this unit only in a complete table or in a document exploring theoretical limits. Handling it correctly costs nothing and demonstrates that the tool applies its rules uniformly, which is the property that makes its ordinary answers trustworthy.
One zebioctet per second equals 1,024 exbioctets per second, 1,180,591,620,717,411,303,424 octets per second, or about 1.181 zettaoctets per second.