| Yottaoctets per second (Yo/s) | Gibibits per second (Gibit/s) |
|---|---|
| 1 Yottaoctet per second | 7.45058059692 × 1015 Gibit/s |
| 2 Yottaoctets per second | 1.49011611938 × 1016 Gibit/s |
| 3 Yottaoctets per second | 2.23517417908 × 1016 Gibit/s |
| 4 Yottaoctets per second | 2.98023223877 × 1016 Gibit/s |
| 5 Yottaoctets per second | 3.72529029846 × 1016 Gibit/s |
| 10 Yottaoctets per second | 7.45058059692 × 1016 Gibit/s |
| 20 Yottaoctets per second | 1.49011611938 × 1017 Gibit/s |
| 25 Yottaoctets per second | 1.86264514923 × 1017 Gibit/s |
| 50 Yottaoctets per second | 3.72529029846 × 1017 Gibit/s |
| 100 Yottaoctets per second | 7.45058059692 × 1017 Gibit/s |
| Reference | Yottaoctets per second (Yo/s) | Gibibits per second (Gibit/s) |
|---|---|---|
| A dial-up modem | 7 × 10-21 Yo/s | 0.0000521541 Gibit/s |
| Typical home broadband | 1.25 × 10-17 Yo/s | 0.0931323 Gibit/s |
| Gigabit Ethernet | 1.25 × 10-16 Yo/s | 0.931323 Gibit/s |
| Streaming a 4K film | 3.125 × 10-18 Yo/s | 0.0232831 Gibit/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 gibibit per second is a unit of data transfer rate equal to 1,073,741,824 bits per second. Its symbol is Gibit/s. It is the binary counterpart of the gigabit per second, and the two now differ by 7.4 per cent, which is enough to matter in any engineering specification.
The unit belongs to the inside of a machine rather than to the network. Memory buses, processor interconnects and the links between chips on the same board all move a power-of-two number of bits per clock cycle, so their throughput is naturally expressed with a binary prefix. A bus sixty-four bits wide clocked at a given frequency delivers a rate that is a binary multiple of that frequency.
Networking, by contrast, is decimal all the way down. Gigabit Ethernet carries exactly one thousand million bits per second, not 1,073,741,824, and the symbol rate on the wire is chosen to make that so. Confusing the two overstates a link's capacity by seven per cent, which in a capacity plan is the difference between adequate and insufficient.
In octets a gibibit per second is 134,217,728, or 128 mebioctets per second. That is close to the throughput of a fast mechanical hard drive and well below a modern solid-state drive, so it sits at the point where storage and internal buses meet and where matching their rates becomes a design question.
Benchmark tools are the commonest place to see the unit written correctly. A memory bandwidth test that allocates buffers in powers of two and measures how long they take to traverse naturally reports in gibibits or gibioctets per second, and a well-written tool says so explicitly rather than rounding to the decimal unit.
The reason to insist on the distinction here rather than lower down the scale is arithmetic. At the kibibit the gap was 2.4 per cent and could be ignored; here it is nearly a thirteenth, and it grows by a further 2.4 per cent at every step above. Getting into the habit at this level costs nothing and avoids compounding errors later.
One gibibit per second equals 1,073,741,824 bits per second, 134,217,728 octets per second, or about 1.074 gigabits per second.