Mebibyte to Tebibyte

MB (megabyte) = 1,000,000 bytes (SI decimal). MiB (mebibyte) = 1,048,576 bytes (IEC binary). MiB is 4.86% larger. This gap is why a file manager on Linux showing "512 MiB" of free RAM and a marketing sheet showing "512 MB" of RAM are technically different: the marketing sheet refers to fewer bytes.

The original CD-ROM standard defined capacity as 74 minutes of audio or 650,000,000 bytes. Technically this is 650 MB in SI terms, or approximately 620 MiB (since 650,000,000 ÷ 1,048,576 ≈ 620). However, the CD industry loosely used "MB" to mean 650 × 10⁶ bytes. Some media used 700 MB (≈ 668 MiB). This inconsistency is a classic example of the pre-IEC ambiguity.

Docker reports image sizes in decimal MB (e.g., "docker images" shows 150 MB), but the underlying layer storage on disk uses binary-aligned block sizes. A "150 MB" Docker image actually occupies roughly 143 MiB on disk before compression. Compressed layers further complicate things: a 150 MB uncompressed image might only transfer 50 MB over the network. Container registries like Docker Hub display compressed sizes, while "docker images" shows uncompressed — leading to frequent confusion in CI/CD pipeline size budgets.

One mebibyte (1,048,576 bytes) holds about: one minute of MP3 audio at 128 kbps (≈ 960 kB, so slightly under 1 MiB), a medium-resolution JPEG photo (0.5–2 MiB), about 200 pages of plain text, or the complete text of a short novel. A typical Linux kernel image at boot is 8–12 MiB compressed.

RAM chips are physically organized as binary address grids — each address line doubles the capacity, so sizes must be exact powers of 2 (4 GiB = 2³² bytes, 8 GiB = 2³³ bytes). USB flash drives use NAND flash that is also binary internally, but manufacturers reserve variable amounts for wear levelling, bad block management, and controller firmware. A "64 GB" USB drive might have 64 GiB of raw NAND but only expose 59.6 GiB (64 × 10⁹ ÷ 2³⁰) to the user — the label uses decimal marketing, unlike RAM which honestly reflects binary sizing.

TB (terabyte) = 10¹² bytes = 1,000,000,000,000 bytes (SI decimal). TiB (tebibyte) = 2⁴⁰ bytes = 1,099,511,627,776 bytes (IEC binary). TiB is 9.95% larger. The practical consequence: a 1 TB hard drive (decimal) holds 0.9095 TiB. This 10% gap is the primary reason drive capacity appears lower in the OS than on the box.

ZFS and Btrfs are copy-on-write filesystems designed for TiB-scale pools with built-in features that traditional filesystems lack. ZFS supports inline deduplication — a 10 TiB pool with 40% duplicate data might show 6 TiB of logical usage but only consume 3.6 TiB physically. Btrfs offers transparent compression (zstd), where a 4 TiB dataset of compressible log files might occupy only 1–2 TiB on disk. Both support snapshots that initially consume zero extra space, growing only as data diverges. These features make "used space in TiB" surprisingly complex to report accurately.

Yes. Linux tools (df -h, lsblk) display storage in IEC binary units: KiB, MiB, GiB, TiB. df -h output showing "1.8T" for a 2 TB drive is reporting 1.8 TiB. Modern Linux distributions correctly label these as TiB in technical contexts. This is one of the areas where Linux is more technically precise than Windows or consumer storage labels.

RAID arrays lose capacity to redundancy: RAID 1 mirrors two drives (50% efficiency); RAID 5 loses one drive worth of capacity; RAID 6 loses two drives. A 4-drive RAID 5 array of 2 TB drives has 3 × 2 TB = 6 TB raw usable (decimal), ≈ 5.46 TiB, minus filesystem overhead. Enterprise storage also reserves space for spares, snapshots, and wear levelling, further reducing usable TiB.

No. A tebibyte (TiB) = 2⁴⁰ bytes = 1,099,511,627,776 bytes — about 1.1 trillion bytes. Exactly one trillion bytes = 10¹² bytes = 1 terabyte (TB, decimal). The tebibyte is approximately 10% larger than a trillion bytes. "Terabyte" is often casually used to mean "1 trillion bytes"; "tebibyte" is the precise binary equivalent at 1,024 gibibytes.