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Re: [BackupPC-users] Pool Size larger than Harddrive usage
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From: Bill H. <hud...@ve...> - 2006-03-01 04:34:56
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type"> <title></title> </head> <body bgcolor="#ffffff" text="#000000"> Perhaps this will help: <a class="moz-txt-link-freetext" href="http://physics.nist.gov/cuu/Units/binary.html">http://physics.nist.gov/cuu/Units/binary.html</a> <br> <br> In short, it would be best to use "df -H" to get the disk storage standard of 10^6 for "a MB", rather than "2^20" for MiB. If you want raw numbers, the closest I think you can come is "df --block-size 1000" or "df --block-size 1024".<br> <br> So...GB is power-of-ten, GiB is power-of-two. You're ahead of the curve, Craig, don't change back now...! <br> <br> [A part of my brain sees "<b>mebibyte" </b>and thinks, "WHY do I feel like I did when 8-track tapes went away, and again when my beloved BetaMax tape collection became a museum piece?"]<br> <br> Excerpt from the web page:<br> <br> "<font color="#330099" face="Myriad Roman,Syntax,Gill,Gill Sans,Arial,Helvetica" size="+1">Historical context<sup>*</sup></font> <br> <p><font face="Myriad Roman,Syntax,Gill,Gill Sans,Arial,Helvetica">Once upon a time, computer professionals noticed that 2<sup>10</sup> was very nearly equal to 1000 and started using the SI prefix "kilo" to mean 1024. That worked well enough for a decade or two because everybody who talked kilobytes knew that the term implied 1024 bytes. But, almost overnight a much more numerous "everybody" bought computers, and the trade computer professionals needed to talk to physicists and engineers and even to ordinary people, most of whom know that a kilometer is 1000 meters and a kilogram is 1000 grams.</font> </p> <p><font face="Myriad Roman,Syntax,Gill,Gill Sans,Arial,Helvetica">Then data storage for gigabytes, and even terabytes, became practical, and the storage devices were not constructed on binary trees, which meant that, for many practical purposes, binary arithmetic was less convenient than decimal arithmetic. The result is that today "everybody" does not "know" what a megabyte is. When discussing computer memory, most manufacturers use megabyte to mean <nobr>2<sup>20</sup> = 1 048 576</nobr> bytes, but the manufacturers of computer storage devices usually use the term to mean <nobr>1 000 000</nobr> bytes. Some designers of local area networks have used megabit per second to mean <nobr>1 048 576 bit/s,</nobr> but all telecommunications engineers use it to mean 10<sup>6</sup> bit/s. And if two definitions of the megabyte are not enough, a third megabyte of <nobr>1 024 000 bytes</nobr> is the megabyte used to format the familiar 90 mm (3 1/2 inch), "1.44 MB" diskette. The confusion is real, as is the potential for incompatibility in standards and in implemented systems.</font> </p> <font face="Myriad Roman,Syntax,Gill,Gill Sans,Arial,Helvetica">Faced with this reality, the IEEE Standards Board decided that IEEE standards will use the conventional, internationally adopted, definitions of the SI prefixes. Mega will mean <nobr>1 000 000,</nobr> except that the base-two definition may be used (if such usage is explicitly pointed out on a case-by-case basis) until such time that prefixes for binary multiples are adopted by an appropriate standards body. </font> "<br> <br> <pre class="moz-signature" cols="72">-- Regards, Bill Hudacek "Redundancy is good; triple redundancy is twice as good!" - me </pre> </body> </html> |