| Mebioctets per second (Mio/s) | Zebioctets per second (Zio/s) |
|---|---|
| 1 Mebioctet per second | 8.881784197 × 10-16 Zio/s |
| 2 Mebioctets per second | 1.7763568394 × 10-15 Zio/s |
| 3 Mebioctets per second | 2.6645352591 × 10-15 Zio/s |
| 4 Mebioctets per second | 3.5527136788 × 10-15 Zio/s |
| 5 Mebioctets per second | 4.4408920985 × 10-15 Zio/s |
| 10 Mebioctets per second | 8.881784197 × 10-15 Zio/s |
| 20 Mebioctets per second | 1.7763568394 × 10-14 Zio/s |
| 25 Mebioctets per second | 2.22044604925 × 10-14 Zio/s |
| 50 Mebioctets per second | 4.4408920985 × 10-14 Zio/s |
| 100 Mebioctets per second | 8.881784197 × 10-14 Zio/s |
| Reference | Mebioctets per second (Mio/s) | Zebioctets per second (Zio/s) |
|---|---|---|
| A dial-up modem | 0.00667572 Mio/s | 5.92923 × 10-18 Zio/s |
| Typical home broadband | 11.9209 Mio/s | 1.05879 × 10-14 Zio/s |
| Gigabit Ethernet | 119.209 Mio/s | 1.05879 × 10-13 Zio/s |
| Streaming a 4K film | 2.98023 Mio/s | 2.64698 × 10-15 Zio/s |
The mebioctet per second is a unit of data transfer rate equal to 1,048,576 octets per second, which is 1,024 kibioctets per second. Its symbol is Mio/s. It is the unit that disc benchmarks, copy tools and backup programs report in, and one of the few binary units most people see regularly without noticing.
Storage measurement produces it naturally. A benchmark writes and reads blocks whose size is a power of two, times the operation, and divides. The result is a binary rate, and reporting it as such preserves the arithmetic. A tool that converted to decimal megaoctets would introduce a 4.9 per cent adjustment for no purpose other than to match a marketing convention.
That five per cent is exactly where the two conventions diverge visibly for consumers. A drive advertised at 550 megaoctets per second and measured at 524 mebioctets per second is performing precisely as claimed; the numbers differ only because one is decimal and the other binary. A great deal of complaint about storage performance is this arithmetic misread as a shortfall.
For everyday sizes, one mebioctet per second copies a photograph in three seconds and a two-gigaoctet film in about half an hour. Modern drives run hundreds or thousands of times faster, so the unit is now the resolution at which small differences are reported rather than the scale of the whole figure.
The unit also appears in memory and cache measurements, in database throughput reports and in the output of the low-level commands that write disc images. All of these count in binary blocks because the underlying structures are binary, and all of them report in mebioctets per second because that is what the count divided by the time actually gives.
The habit of writing the lowercase i is worth keeping. It costs one character and it tells a later reader which of two conventions produced the number, which is information that cannot be recovered from context once it has been left out.
One mebioctet per second equals 1,048,576 octets per second, 1,024 kibioctets per second, or about 1.049 megaoctets 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.