| Tebibits (Tibit) | Exbibits (Eibit) |
|---|---|
| 1 Tebibit | 0.000000953674316406 Eibit |
| 2 Tebibits | 0.00000190734863281 Eibit |
| 3 Tebibits | 0.00000286102294922 Eibit |
| 4 Tebibits | 0.00000381469726562 Eibit |
| 5 Tebibits | 0.00000476837158203 Eibit |
| 10 Tebibits | 0.00000953674316406 Eibit |
| 20 Tebibits | 0.0000190734863281 Eibit |
| 25 Tebibits | 0.0000238418579102 Eibit |
| 50 Tebibits | 0.0000476837158203 Eibit |
| 100 Tebibits | 0.0000953674316406 Eibit |
| Reference | Tebibits (Tibit) | Exbibits (Eibit) |
|---|---|---|
| A plain text message (160 characters) | 0.00000000116415 Tibit | 1.11022 × 10-15 Eibit |
| A three-minute MP3 | 0.0000218279 Tibit | 2.08167 × 10-11 Eibit |
| A smartphone photo | 0.0000291038 Tibit | 2.77556 × 10-11 Eibit |
| A high-definition film | 0.0291038 Tibit | 0.0000000277556 Eibit |
| A dual-layer Blu-ray disc | 0.363798 Tibit | 0.000000346945 Eibit |
The tebibit is a unit of digital information equal to 1,099,511,627,776 bits, which is 1,024 gibibits or two to the fortieth power. Its symbol is Tibit. It is the binary counterpart of the terabit, and the two now differ by 10 per cent, the point at which the distinction stops being pedantic and starts being financial.
That ten per cent is the reason the IEC prefixes exist. At the kibibit the discrepancy was 2.4 per cent and could be waved away; here it is a tenth of the quantity. In a contract for storage hardware, in a service agreement that guarantees capacity, or in a specification that a supplier must meet, a tenth is the difference between compliance and breach.
The unit's real home is flash memory, where dies are now made with capacities of one tebibit and above by stacking cell layers vertically. A modern flash die may hold a tebibit or two, and a package containing eight of them holds a teraoctet of raw capacity, from which spare blocks and management overhead are subtracted before anything reaches the user.
A tebibit is 137,438,953,472 octets, or 128 gibioctets. In practical terms it is the storage of a mid-range phone, or a couple of hours of uncompressed high-resolution video. The unit describes the raw material of storage devices rather than anything a person handles directly.
Filesystems also count in binary at this scale. A volume reported as 16 tebibytes by one tool and 17.6 terabytes by another is the same volume, and the difference is entirely in the base of the arithmetic. Anyone administering storage learns to check which convention a tool uses before comparing two numbers from different sources.
Correct notation is Tibit, with the capital T and lowercase i. It appears in flash memory datasheets, in filesystem documentation and in standards, and almost nowhere else. The presence of that lowercase i is the only reliable signal that a figure is binary, which is why careful technical writing uses it even when the difference seems small.
One tebibit equals 1,099,511,627,776 bits, 1,024 gibibits, 137,438,953,472 octets, or about 1.100 terabits.
The exbibit is a unit of digital information equal to two to the sixtieth power bits, which is 1,024 pebibits. Its symbol is Eibit. It is the binary counterpart of the exabit, and the two now differ by 15.3 per cent.
Two to the sixtieth is a number with a particular importance in computing, because sixty is close to the sixty-four bits of a modern processor address. A 64-bit machine can address sixteen exbioctets of memory, and that figure — 16 EiB — is the theoretical ceiling of the entire architecture. It appears in processor manuals, in operating system documentation and in the specification of every 64-bit filesystem.
No machine comes close to using that range. Current processors implement only forty-eight or fifty-seven of those sixty-four address bits, because wiring the full width would cost silicon for an address space nobody can fill. The unused bits are reserved, and widening the implementation is a straightforward matter whenever memory sizes make it worthwhile, which is the point of having chosen sixty-four in the first place.
An exbibit is 144,115,188,075,855,872 octets, or 128 pebioctets. That is more storage than any single organisation holds, and comparable to the combined annual output of a large part of the storage industry. As with all the larger binary units, it describes limits and capacities in specifications rather than anything that has been built.
The unit is also where filesystem designers set their maximum sizes. Filesystems built around 64-bit block pointers naturally have limits at exact powers of two, and several widely deployed ones specify maximum volume sizes in exbioctets. Those numbers are not aspirations; they are the arithmetic consequence of the pointer width, and they will hold until the architecture changes.
Reading the symbol correctly matters here. Eibit is the exbibit; Ebit is the exabit; EB and EiB are the octet forms of each. In a document where a fifteen per cent difference is significant — and at this scale it always is — the presence or absence of the lowercase i carries the entire meaning.
One exbibit equals 1,024 pebibits, 144,115,188,075,855,872 octets, or about 1.153 exabits.