track = 10649 "Kb", which they write as "10.66Mb", so 1 "Mb" = 1000 "Kb") (256 Bytes per sector, 32 Sectors/tk = 8192 bytes, which they write as "8.20Kb" per track) "Storage capacity of 10, 20, 30, or 40 megabytes" 4.34M bits/second transfer rate" Apple Disk III data sheet "Formatted Data Capacity: 140K bytes" Apple uses K in a binary sense since the actual formatted capacity is 35 tracks * 16 Sectors * 256 bytes = 140 KiB = 143.360 kB 1982 Brochure for the IBM Personal Computer (PC) "User memory: 16KB to more than 512KB", "single-sided 160KB or double-sided 320KB diskette drives" IBM Technical Reference: Personal Computer Hardware Reference Library "The drives are soft sectored, single or double sided, with 40 tracks per side. They are Modified Frequency Modulation (MFM) coded in 512 byte sectors, giving a formatted capacity of 163,840 bytes per drive for single sided and 327,680 bytes per drive for double sided." Seagate ST 506/412 OEM Manual "Total formatted capacity [...] is 5/10 megabytes (32 sectors per track, 256 bytes per sector, 612/1224 tracks)" 1983 IBM S/360 S/370 Principles Of Operation GA22-7000 includes as statement: "In this publication, the letters K, M and G denote the multipliers 210, 220 and 230 respectively. Although the letters are borrowed from the decimal system and stand for kilo 103, mega 106 and giga 109 they do not have decimal meaning but instead present the power of 2 closest to the corresponding power of 10." IBM 341 4-inch Diskette Drive unformatted capacity "358,087 bytes" "Total unformatted capacity (in kilobytes): 358.0" Maxtor XT-1000 brochure "Capacity, unformatted" 9.57 MB per surface = 10,416 bytes per track × 918 tracks per surface = 9,561,888 byte (decimal MB) Shugart Associates SA300/350 Data Sheet published c. November 1983 (one of the first MIC standard 3.5" FDDs) contains capacity specifications as follows: Shugart Associates, one of the leading FD companies used k in a decimal sense. 1984 The Macintosh Operating System is the earliest known operating system using the prefix K in a binary sense to report memory size and HDD capacity. In the original 1984 Apple Macintosh ad, page 8, Apple characterized its 3 floppy disk as "400K," that is, 800×512 byte sectors or 409,600 bytes = 400 KiB. Similarly, the February 1984 Byte Magazine review describes the FD as "400K bytes". 1985 Exabyte Corp. founded September 1985. Apple introduced Macintosh Finder 5.0 with HFS