2^10 (1,024) is 2.4 percent larger than 10^3 (1,000), which in turn is 2.34375 percent smaller than 2^10 (1,024). This percent difference compounds exponentially with every three additional decimal zeroes or ten additional binary zeroes, and reaches nearly 50 percent different at 10^51, FWIW.
Bill Fairchild Programmer Rocket Software 408 Chamberlain Park Lane * Franklin, TN 37069-2526 * USA t: +1.617.614.4503 * e: bfairch...@rocketsoftware.com * w: www.rocketsoftware.com -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of John Gilmore Sent: Wednesday, December 26, 2012 11:36 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Large table in memory Tom, Thank you for the silent correction. The 'exa' in 'exabytes' is certainly a radical improvement over 'exo', which was not confidence-inspiring. That said, it seems to me that for these magnitudes the binary prefix 'exbi' should be used. We have (2^10)^6 = 115_2921_5046_0684_6976 exbibytes (10^3)^6 = 100_0000_0000_0000_0000 exabytes and there is thus a non-trivial 13+% difference between these two numbers. All this began with the notion of the rough equivalence of 2^10 = 1024 and 10^3 = 1000, which is a 2+% difference. The practical difference between a kibibyte and a kilobyte was thus unimportant, particularly in discussions among highly numerate people who understood what sort of approximation they were using. Things have, however, changed. We are now often dealing with the easily confused innumerate, and the differences are large enough to make dissimulation attractive to some, certainly not all, marketing types. John Gilmore, Ashland, MA 01721 - USA ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
