| Tebioctets (Tio) | Yottaoctets (Yo) |
|---|---|
| 1 Tebioctet | 1.09951162778 × 10-12 Yo |
| 2 Tebioctets | 2.19902325555 × 10-12 Yo |
| 3 Tebioctets | 3.29853488333 × 10-12 Yo |
| 4 Tebioctets | 4.3980465111 × 10-12 Yo |
| 5 Tebioctets | 5.49755813888 × 10-12 Yo |
| 10 Tebioctets | 1.09951162778 × 10-11 Yo |
| 20 Tebioctets | 2.19902325555 × 10-11 Yo |
| 25 Tebioctets | 2.74877906944 × 10-11 Yo |
| 50 Tebioctets | 5.49755813888 × 10-11 Yo |
| 100 Tebioctets | 1.09951162778 × 10-10 Yo |
| Reference | Tebioctets (Tio) | Yottaoctets (Yo) |
|---|---|---|
| A plain text message (160 characters) | 1.45519 × 10-10 Tio | 1.6 × 10-22 Yo |
| A three-minute MP3 | 0.00000272848 Tio | 3 × 10-18 Yo |
| A smartphone photo | 0.00000363798 Tio | 4 × 10-18 Yo |
| A high-definition film | 0.00363798 Tio | 4 × 10-15 Yo |
| A dual-layer Blu-ray disc | 0.0454747 Tio | 5 × 10-14 Yo |
The tebioctet is a unit of digital information equal to 1,099,511,627,776 octets, which is 1,024 gibioctets. Its symbol is Tio. It is the binary counterpart of the teraoctet, and at this level the two differ by 10 per cent — the gap that produces the most familiar complaint in consumer computing.
That complaint runs as follows. A drive is sold as one teraoctet, holds exactly one million million octets, and the operating system reports 931 gigaoctets. What it is actually reporting is 0.909 tebioctets, expressed with the wrong label. Nothing is missing from the drive; the number has simply been divided by 1,024 three times and then written with a decimal prefix.
Storage administration lives in this unit. Volume sizes, RAID array capacities, snapshot reserves and quota limits are all quoted in tebioctets by the tools that manage them, because the underlying allocation units are powers of two. A filesystem asked to create a 10-teraoctet volume and one asked to create a 10-tebioctet volume will produce visibly different results.
The difference matters commercially as well as technically. Cloud storage priced per teraoctet and cloud storage priced per tebioctet differ by a tenth in the quantity delivered for the same price, and a contract that does not say which is being used is genuinely ambiguous. Careful procurement documents specify the unit explicitly for exactly this reason.
A tebioctet holds around a quarter of a million photographs, two hundred hours of high-definition video, or the complete text of every book in a large public library many times over. In a household it is more storage than a lifetime of ordinary files will use; in a video production company it is a few days of work.
The correct symbol Tio appears in filesystem tools, in storage array documentation and in standards, and it is worth using even when the audience is unlikely to notice. A figure written with a binary prefix can be converted correctly by anyone who reads it later; one written ambiguously cannot be repaired.
One tebioctet equals 1,099,511,627,776 octets, 1,024 gibioctets, 8 tebibits, or about 1.100 teraoctets.
The yottaoctet is a unit of digital information equal to a thousand zettaoctets, or a septillion octets — a one followed by twenty-four zeros. Its symbol is Yo. Nothing that exists is measured in yottaoctets; the unit describes a quantity of data the world has not yet produced.
The total data held by humanity is currently estimated in the low hundreds of zettaoctets, so the world is a small fraction of the way to its first yottaoctet. On the growth rates of the last two decades, that threshold would be crossed sometime in the 2040s, though every long-range forecast in this field has been wrong in both directions.
The physical obstacles are severe. At the storage densities of current hard drives, a yottaoctet would need something like a hundred billion units. Manufacturing them at present rates would take centuries, powering them would need the electrical output of many countries, and housing them would require a building programme without precedent. The number is not absurd, but it is far beyond the current industrial base.
Research into higher-density storage exists partly because of this ceiling. DNA data storage, which encodes information in synthetic genetic sequences, offers densities millions of times higher than magnetic media, and a yottaoctet of DNA would fit in a room rather than a continent. Reading and writing it remain slow and costly, but the density argument is what keeps the field funded.
The yottaoctet also appears in claims that turn out to be exaggerated. Reports that intelligence agencies were building yottaoctet-scale facilities circulated widely in the 2010s and were not supported by the construction, the power supply or the storage market. Any claim about a yottaoctet of anything can be checked against total world manufacturing, which is a useful discipline.
Between 1991 and 2022 the yotta prefix was the top of the metric ladder, which is why it was the natural unit for speculative claims. The addition of ronna and quetta in 2022 gave the system three more decimal orders above it, and it is telling that this was done partly because data quantities were approaching the old ceiling.
One yottaoctet equals 1,000 zettaoctets, 1,000,000,000,000,000 gigaoctets, 8 yottabits, or about 0.8272 yobioctets.