What is data storage and how are units defined?
Data storage refers to the retention of digital information in electronic systems. As data volumes exploded, standardized units became essential for measurement. The international system of units (SI) established decimal-based prefixes where:
- 1 exabyte (EB) = 10¹⁸ bytes (1,000,000,000,000,000,000 bytes)
- 1 zettabit (Zbit) = 10²¹ bits (1,000,000,000,000,000,000,000 bits)
Simultaneously, the International Electrotechnical Commission (IEC) created binary prefixes for computing systems:
- 1 exbibyte (EiB) = 2⁶⁰ bytes (1,152,921,504,606,846,976 bytes)
- 1 zebibit (Zibit) = 2⁷⁰ bits (1,180,591,620,717,411,303,424 bits)
The critical distinction lies in the base system: SI uses base-10 (powers of 10) while IEC uses base-2 (powers of 2).
Comparison of data storage systems
| System | Base | Byte Units | Bit Units | Standard | Primary Usage |
|---|---|---|---|---|---|
| SI (decimal) | 10 | EB (exabyte) | Zbit (zettabit) | ISO/IEC | Storage manufacturers |
| IEC (binary) | 2 | EiB (exbibyte) | Zibit (zebibit) | IEC 60027-2 | Operating systems |
Key conversion formulas
All conversions must account for both the base system (decimal vs binary) and the unit type (bits vs bytes). Remember: 1 byte = 8 bits.
SI to SI conversions
IEC to IEC conversions
Cross-system conversions
Practical conversion examples
Corporate data migration
A cloud provider needs to transfer 5.5 EB of archived data to a new storage system rated in zettabits. Using the SI conversion:
This helps determine required network bandwidth.
Scientific computing
A research facility has 2.3 EiB of genomic data. To compare with internet backbone capacity (measured in Zibit):
Revealing it would take approximately 56 transfers to move all data across a 1 Zibit/s connection.
Storage procurement
A company buys 100 EB of storage but the OS reports only 90.7 EiB. This discrepancy occurs because:
Plus formatting overhead explains the difference - not defective hardware.
Why two measurement systems exist
- Historical context: Early computing used binary addressing where 1,024 bytes naturally equaled 2¹⁰ bytes.
- Technical accuracy: Memory chips and storage allocation fundamentally operate in binary.
- Marketing vs reality: Drive manufacturers use decimal units (appearing larger) while OSes use binary for precise allocation.
- Standardization efforts: IEC formally defined binary prefixes in 1998 to resolve confusion.
Real-world applications of large-unit conversions
- Internet infrastructure: Global internet traffic reached 4.8 ZB/year in 2022 (Cisco).
- Astronomy: Square Kilometer Array telescope generates ~1 EB daily.
- Business intelligence: Walmart processes ~40 PB daily (0.00032 Zbit).
- Cloud economics: AWS charges ~$0.023/GB-month, making 1 EB storage cost ~$23 million monthly.
- Security: Detecting threats in real-time requires converting between network bits (Zbit) and storage bytes (EB).
Historical evolution of data units
The term “byte” was coined by Werner Buchholz in 1956. As data grew:
- 1975: “Exa-” prefix established by SI.
- 1991: 1GB drives became commercially available.
- 2008: World’s data surpassed 1 EB.
- 2016: IEC formalized zebibit/zebibyte to prevent confusion.
- 2020: Global datasphere reached 64 ZB (IDC).
Frequently asked questions
Why does my 1 EB drive show less capacity?
Storage manufacturers use SI units (1 EB = 1,000⁶ bytes) while operating systems use IEC units (1 EiB = 1,024⁶ bytes). The conversion is:
How to convert 3.5 Zibit to EB?
First convert Zibit to bits, then to bytes, then adjust bases:
What’s larger: yottabyte or yobibyte?
1 yottabyte (YB) = 10²⁴ bytes
1 yobibyte (YiB) = 2⁸⁰ bytes ≈ 1.2089 × 10²⁴ bytes
Thus 1 YiB is about 21% larger than 1 YB.
How many exabytes in a zettabit?
Since 1 Zbit = 10²¹ bits and 1 EB = 8 × 10¹⁸ bits:
1 Zbit equals exactly 125 EB in SI units.