| Mebioctets per second (Mio/s) | Exbioctets per second (Eio/s) |
|---|---|
| 1 Mebioctet per second | 9.09494701773 × 10-13 Eio/s |
| 2 Mebioctets per second | 1.81898940355 × 10-12 Eio/s |
| 3 Mebioctets per second | 2.72848410532 × 10-12 Eio/s |
| 4 Mebioctets per second | 3.63797880709 × 10-12 Eio/s |
| 5 Mebioctets per second | 4.54747350886 × 10-12 Eio/s |
| 10 Mebioctets per second | 9.09494701773 × 10-12 Eio/s |
| 20 Mebioctets per second | 1.81898940355 × 10-11 Eio/s |
| 25 Mebioctets per second | 2.27373675443 × 10-11 Eio/s |
| 50 Mebioctets per second | 4.54747350886 × 10-11 Eio/s |
| 100 Mebioctets per second | 9.09494701773 × 10-11 Eio/s |
| Reference | Mebioctets per second (Mio/s) | Exbioctets per second (Eio/s) |
|---|---|---|
| A dial-up modem | 0.00667572 Mio/s | 6.07153 × 10-15 Eio/s |
| Typical home broadband | 11.9209 Mio/s | 1.0842 × 10-11 Eio/s |
| Gigabit Ethernet | 119.209 Mio/s | 1.0842 × 10-10 Eio/s |
| Streaming a 4K film | 2.98023 Mio/s | 2.71051 × 10-12 Eio/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 exbioctet per second is a unit of data transfer rate equal to 1,024 pebioctets per second, or two to the sixtieth power octets per second. Its symbol is Eio/s. It is the binary counterpart of the exaoctet per second, and the two differ by 15.3 per cent.
No machine, network or aggregate reaches this rate. An exbioctet per second is more than eight times the total instantaneous traffic of the entire internet, and it would move the world's whole stock of stored data in a matter of minutes. The unit describes a capacity with no source that could supply it and no destination that could take it in.
Two to the sixtieth is nevertheless a familiar number in computing, because it is the size of the address space a 64-bit machine can reach in octets divided by sixteen. The same power of two turns up in filesystem limits, in memory maps and in the design of every system built on that architecture, so the quantity is well known even though no rate approaches it.
The unit exists because the IEC series was defined completely. Every binary prefix pairs with every unit, exactly as every metric prefix does, so that a reader who has never seen Eio/s can decode it from the prefix alone. A system with gaps would need a table of permitted combinations, which is precisely what a rule-based system exists to avoid.
The difference from the decimal unit is worth restating at each level because it compounds. At the kibioctet it was 2.4 per cent, here it is more than an eighth, and at the yobioctet it will be more than a fifth. That growth is the reason the binary prefixes were created, and it is why the lowercase i has to be written even in figures nobody will check.
For a converter, the treatment is mechanical: six multiplications by 1,024 from octets, or the equivalent divisions coming down. The value of doing it correctly is not that anyone will use the result, but that a tool which handles every case the same way can be trusted on the cases that matter.
One exbioctet per second equals 1,024 pebioctets per second, 1,152,921,504,606,846,976 octets per second, or about 1.153 exaoctets per second.