| Yottaoctets per second (Yo/s) | Exbibits per second (Eibit/s) |
|---|---|
| 1 Yottaoctet per second | 6938893.90391 Eibit/s |
| 2 Yottaoctets per second | 13877787.8078 Eibit/s |
| 3 Yottaoctets per second | 20816681.7117 Eibit/s |
| 4 Yottaoctets per second | 27755575.6156 Eibit/s |
| 5 Yottaoctets per second | 34694469.5195 Eibit/s |
| 10 Yottaoctets per second | 69388939.0391 Eibit/s |
| 20 Yottaoctets per second | 138777878.078 Eibit/s |
| 25 Yottaoctets per second | 173472347.598 Eibit/s |
| 50 Yottaoctets per second | 346944695.195 Eibit/s |
| 100 Yottaoctets per second | 693889390.391 Eibit/s |
| Reference | Yottaoctets per second (Yo/s) | Exbibits per second (Eibit/s) |
|---|---|---|
| A dial-up modem | 7 × 10-21 Yo/s | 4.85723 × 10-14 Eibit/s |
| Typical home broadband | 1.25 × 10-17 Yo/s | 8.67362 × 10-11 Eibit/s |
| Gigabit Ethernet | 1.25 × 10-16 Yo/s | 8.67362 × 10-10 Eibit/s |
| Streaming a 4K film | 3.125 × 10-18 Yo/s | 2.1684 × 10-11 Eibit/s |
The yottaoctet per second is a unit of data transfer rate equal to a thousand zettaoctets per second, or eight yottabits per second. Its symbol is Yo/s. It is the largest transfer rate the metric system named for thirty years, and it stands at the point where the question stops being one of engineering and becomes one of physics.
The physical limits are real and can be stated. Any communication channel has a capacity set by its bandwidth and its signal-to-noise ratio, a result Claude Shannon proved in 1948. Pushing a rate higher means using more bandwidth, more power, or more parallel channels, and each of those has a cost that grows without limit as the rate does.
Energy sets the sharpest bound. Thermodynamics requires a minimum energy to distinguish one state from another at a given temperature, and although practical systems are many orders of magnitude above that floor, the floor is not zero. At a yottaoctet per second even the theoretical minimum becomes a substantial power, and every real system multiplies it by a large factor.
There is also a limit from the medium itself. A single optical fibre has a capacity ceiling set by non-linear effects in the glass, which grow with the light power carried, so raising the power eventually degrades the signal rather than improving it. Reaching a yottaoctet per second would require something like a hundred billion fibres running at today's records simultaneously, which is a construction problem rather than a communication one.
None of this makes the unit meaningless. It is properly defined, it converts by the same rule as every other, and it appears in discussions of theoretical limits and in complete tables of the prefix system. A measurement system that stopped naming quantities at the point where engineering stops would be less useful, not more.
Since 2022 the metric system has had ronna and quetta above yotta, so this is no longer the top of the ladder. That extension was driven by data quantities rather than by rates, and nothing in transmission has yet given a reason to write a rate above this one.
One yottaoctet per second equals 1,000 zettaoctets per second, 8 yottabits per second, or about 0.8272 yobioctets per second.
The exbibit per second is a unit of data transfer rate equal to two to the sixtieth power bits per second, which is 1,024 pebibits per second. Its symbol is Eibit/s. It is the binary counterpart of the exabit per second, and the two differ by 15.3 per cent.
That fifteen per cent is more than the margin most engineering work allows anywhere. A quantity stated in the wrong convention at this level is not slightly imprecise but plainly wrong, and no amount of context recovers the intended figure once it has been written ambiguously. This is the situation the IEC prefixes were introduced to prevent.
No physical link approaches this rate. The unit describes aggregates: the total instantaneous traffic of the whole internet is roughly an exabit per second, so a binary exbibit per second is fifteen per cent more than everything moving on every network on the planet at a given moment.
Where a binary figure of this size arises naturally is in address arithmetic rather than in transmission. Two to the sixtieth is a number that appears throughout the design of 64-bit systems, and any rate derived from filling or traversing such an address space in a fixed time is naturally binary. Those calculations are theoretical, but they are the reason the unit is defined rather than left unnamed.
In octets an exbibit per second is 144,115,188,075,855,872, or 128 pebioctets per second. That is more storage moved per second than the world manufactures in several years, which is a way of saying that no source and no destination for such a flow could exist.
For a converter the treatment is mechanical and must be exact. Eibit/s and Ebit/s differ by an eighth, and a tool that treats them as interchangeable has introduced an error larger than the difference between many neighbouring units. The lowercase i is not decoration.
One exbibit per second equals 1,024 pebibits per second, 144,115,188,075,855,872 octets per second, or about 1.153 exabits per second.