Exabit to Kibibyte

One exabit = 10¹⁸ bits = 125,000 terabytes = 125 petabytes. If every person on Earth (8 billion people) each stored 15 GB of data — roughly a modern smartphone's photos and messages — the total would be about 120 exabytes, or about 960 exabits. The entire human genome is about 1.5 GB; sequencing every person on Earth would produce about 12 exabytes of data.

Cisco's annual internet traffic reports estimated global IP traffic at roughly 4.8 exabytes per day in 2022, rising about 20% per year. Expressed in bits, that's about 38 exabits per day or roughly 440 petabits per second continuously. Video streaming accounts for over 60% of total internet traffic volume.

Data gravity is the principle that massive datasets attract applications, services, and additional data toward them — rather than being moved to where processing occurs. At exabit scale, physically transferring data becomes impractical: moving 1 exabit over a 100 Gbps link takes 116 days. Instead, companies deploy compute resources alongside the data. This effect drives cloud concentration — once an organisation stores exabits in AWS or Azure, the cost and latency of moving that data elsewhere creates powerful vendor lock-in, shaping the economics of the entire cloud industry.

The Square Kilometer Array (SKA), under construction in Australia and South Africa, will be the world's largest radio telescope. Its thousands of antennas will collectively produce roughly 1 exabit of raw sensor data per day — more than the entire global internet traffic of the early 2000s. This data cannot be stored in full; instead, on-site supercomputers reduce it by a factor of ~10,000 in real time, keeping only scientifically relevant signals. The SKA illustrates how radio astronomy pushes data processing to extreme scales that rival commercial internet infrastructure.

At 1 Gbps (a fast home connection), downloading 1 exabit would take 1 billion seconds — about 31.7 years. At 1 Tbps (a high-end data center link), it would take 1 million seconds, or about 11.6 days. This illustrates why exabit-scale data movements require massively parallel infrastructure — no single link or device handles exabit transfers directly.

KB (kilobyte, SI) = 1,000 bytes. KiB (kibibyte, IEC binary) = 1,024 bytes. The difference is 24 bytes (2.4%) — small individually but the source of the well-known discrepancy between storage manufacturer labels and OS-reported sizes. Storage manufacturers use KB = 1,000 bytes; operating systems traditionally used KB = 1,024 bytes (now correctly called KiB).

Linux memory management, filesystem block sizes, and page sizes are all powers of 2 (typically 4,096 bytes = 4 KiB). Using kibibytes aligns with the physical hardware structure. The GNU coreutils (df, du, ls -h) display sizes in KiB, MiB, GiB by default for consistency with how the kernel allocates memory and disk blocks — decimal kilobytes would produce fractional values for normal aligned allocations.

Most languages expose both conventions depending on the API. Java's Runtime.totalMemory() returns bytes aligned to KiB (binary), but Files.size() returns raw byte counts that file managers may display as decimal KB. Python's os.path.getsize() returns bytes — the developer chooses how to format. Go's humanize library defaults to IEC (KiB) while many JavaScript libraries default to SI (KB). This inconsistency means the same file can appear as different sizes across tools written in different languages.

A memory page is the smallest unit of memory the OS allocates from physical RAM. Most modern CPUs use 4 KiB (4,096 byte) pages; some support 2 MiB or 1 GiB "huge pages" for performance. Every memory allocation is rounded up to the nearest page boundary. This binary alignment is why computer memory sizes are always powers of 2 (4 GB, 8 GB, 16 GB RAM) rather than round decimal numbers (5 GB, 10 GB).

The 3.5-inch floppy's capacity was 1,474,560 bytes — which is neither 1.44 MB (1,440,000 bytes) nor 1.44 MiB (1,509,949 bytes). The label came from a hybrid calculation: 80 tracks × 2 sides × 18 sectors × 512 bytes = 1,474,560 bytes, then divided by 1,000 to get 1,474.56 KB, then divided by 1,024 to get "1.44 MB." This mix of decimal and binary division in the same label is one of the most famous unit blunders in computing history.