mrb's blog

Decimal Prefixes Are More Common Than Binary Prefixes In The Computer Industry

Keywords: hardware standard

Everytime a power-of-10 versus power-of-2 debate emerges, I like to remind people that contrary to common belief, decimal prefixes (as in 1kB = 1000 bytes) are much more commonly used than binary prefixes in the computer industry, like this page from Colin Percival, author of Tarsnap, states. The only few places where binary prefixes are used are to refer to RAM capacity and file sizes, whereas decimal prefixes apply to all other areas and all units (not "only bitrates"): storage capacity, clock frequency, stream bandwidth, baud, pixel numbers, data throughput, processing power, etc.

  • A 32 GB USB flash drive is 32 * 10^9 byte (power of 10)
  • A 16 GB SD card is 16 * 10^9 byte (power of 10)
  • A 50 GB dual-layer Blu-ray Disc is 50 * 10^9 byte (power of 10)
  • A 4.7 GB single-layer DVD is 4.7 * 10^9 byte (power of 10)
  • A 2.5 GHz processor is 2.5 * 10^9 Hz (power of 10)
  • A PC6400 (as in 6400 MByte/s) memory module is 6400 * 10^6 byte/s (power of 10)
  • A 25.6 GFLOPS CPU core is 25.6 * 10^9 FLOPS (power of 10)
  • A 128 kbit/s audio stream is 128 * 10^3 bit/s (power of 10)
  • An 8 kbaud V.92 modem is 8 * 10^3 baud (power of 10)
  • A 6 Mpixel digital camera is 6 * 10^6 pixel (power of 10)
  • A 4000 MB/s HyperTransport link is 4000 * 10^6 byte/s (power of 10)
  • A 480 Mbit/s USB2 link is 480 * 10^6 bit/s (power of 10)
  • A 5.0 Gbit/s PCI-E 2.0 lane (after 8b/10b encoding) is 5.0 * 10^9 bit/s (power of 10)
  • A 500 MB/s PCI-E 2.0 lane (before 8b/10b encoding) is 500 * 10^6 byte/s (power of 10)
  • A 1 Gbit/s ethernet card is 1 * 10^9 bit/s (power of 10)
  • A 54 Mbit/s 802.11g network is 54 * 10^6 bit/s (power of 10)
  • A 6.0 Gbit/s SATA link (after 8b/10b encoding) is 6.0 * 10^9 bit/s (power of 10)
  • A 600 MB/s SATA link (before 8b/10b encoding) is 600 * 10^6 byte/s (power of 10)
  • A 6 Mbit/s DSL line is 6 * 10^6 bit/s (power of 10)
  • Curiosity: a 1.44 MByte floppy disk is 1.44 * 1000 * 1024 byte (mix of power of 10 and 2)
  • And of course, a 3.0 TByte hard disk drive is 3.0 * 10^12 byte (power of 10)
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