| Mebioctets per second (Mio/s) | Exaoctets per second (Eo/s) |
|---|---|
| 1 Mebioctet per second | 1.048576 × 10-12 Eo/s |
| 2 Mebioctets per second | 2.097152 × 10-12 Eo/s |
| 3 Mebioctets per second | 3.145728 × 10-12 Eo/s |
| 4 Mebioctets per second | 4.194304 × 10-12 Eo/s |
| 5 Mebioctets per second | 5.24288 × 10-12 Eo/s |
| 10 Mebioctets per second | 1.048576 × 10-11 Eo/s |
| 20 Mebioctets per second | 2.097152 × 10-11 Eo/s |
| 25 Mebioctets per second | 2.62144 × 10-11 Eo/s |
| 50 Mebioctets per second | 5.24288 × 10-11 Eo/s |
| 100 Mebioctets per second | 1.048576 × 10-10 Eo/s |
| Reference | Mebioctets per second (Mio/s) | Exaoctets per second (Eo/s) |
|---|---|---|
| A dial-up modem | 0.00667572 Mio/s | 7 × 10-15 Eo/s |
| Typical home broadband | 11.9209 Mio/s | 1.25 × 10-11 Eo/s |
| Gigabit Ethernet | 119.209 Mio/s | 1.25 × 10-10 Eo/s |
| Streaming a 4K film | 2.98023 Mio/s | 3.125 × 10-12 Eo/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 exaoctet per second is a unit of data transfer rate equal to a thousand petaoctets per second, or eight exabits per second. Its symbol is Eo/s. Nothing built runs at this rate: it is about eight times the total traffic of the entire internet, counted across every network on the planet at once.
The unit is useful mainly for thought experiments about limits. If every hard drive and flash chip manufactured in a year were read simultaneously at full speed, the combined rate would be in this range. So would the total output of every camera sensor in every phone on Earth if they all recorded at once. These are sums over the whole world's hardware, not rates any system experiences.
There is one situation in which very large data volumes really do move faster than any network, and it puts the unit in perspective. Physically shipping a container of hard drives across an ocean transfers more data per second, averaged over the journey, than any cable. A shipping container holding a few exaoctets crossing the Atlantic in a week works out to several gigaoctets per second, and a truck of drives driven across a city beats almost any local link.
That calculation is not a joke; cloud providers offer it as a service. When a customer needs to move petaoctets into a data centre, the provider ships a lorry full of storage rather than attempting the transfer over a network, because the network would take months. The bandwidth of a vehicle is enormous, though its latency is measured in days.
For the unit itself, an exaoctet per second is 125 petaoctets per second, and it would transfer the world's entire stock of stored data — a few hundred zettaoctets — in about a week of continuous running. No mechanism exists to feed such a link, and none is being designed.
A converter must nevertheless handle the unit, because it appears in aggregate capacity models, in academic papers on the theoretical limits of communication, and in any table that lists the metric prefixes completely. A quantity does not need a use for its name to be well formed.
One exaoctet per second equals 1,000 petaoctets per second, 8 exabits per second, or about 0.8674 exbioctets per second.