On Monday, December 08, 2014 8:12 PM Fred Cisin [mailto:cisin at xenosoft.com] <snip> honest binary Megabytes of 1,048,576 I looked for but could not find a screenshot of very early PCDOS FDISKs, the later ones I've found all include the statement 1 MB = 1,048,576 bytes so by that time Microsoft and IBM were indeed "honest" unlike Apple. FWIW, The MS-DOS Encyclopedia (c) 1988 which covers thru DOS 3.3 shows the "Display Partition Data" option as giving capacity in the number of cylinders, not a particularly useful measurement but not misleading. FORMAT and CHKDSK all report in decimal digits without commas. Would like to see a screenshot for an early FDISK Option 1 using binary prefixes before I concede that Microsoft/IBM DOS used but did not disclose binary prefixes before Apple <snip> some other manufacturers, they rounded DOWN, not UP, AND they did not use excessive "significant digits". competitors to cover bad sectors) ((In apthecary measures, there are THREE Scruples in every DRAM!)) The published Seagate specification for ST225 that I have states the formatted capacity = 21.4 MB comprising exactly 41,820 x 512 byte sectors = 21.411.840 bytes = 21.4 MB BTW the reason I picked the ST225 as an example rather than the ST412 is that Seagate specified the formatted ST412 with 32 x 256 byte sectors per track giving precisely 10.0 MB (10.027008 MB). IBM in the PC chose to go to 17 x 512 Bytes sectors per track thereby increasing the formatted capacity to 10.7 MB or 10.4 MiB. So a Seagate ST412 used with any of the several IBM PC compatible controllers actually had a dram more than Seagate specified, but in both cases more than 10.0; confusing perhaps but no basis for complaining. But they soon changed to 512 byte sectors and that dram went away. I really don't think Seagate was any more scrupulous than its competition in specifying its drives, as near as I can tell they rounded off, but even if they rounded down it was in the third or higher digit so we are talking about a relatively small number when compared to the confusion caused by binary prefixes. Tom