I guess many of us new it already, I did many treat the K and k pretty bad and unclear!
awafully that Ki.. couldn't prevail. I hope it will! >From: "kilopascal" <[EMAIL PROTECTED]> >Reply-To: [EMAIL PROTECTED] >To: "U.S. Metric Association" <[EMAIL PROTECTED]> >Subject: [USMA:17252] Binary Prefixes >Date: Sun, 6 Jan 2002 00:43:37 -0500 > >2002-01-06 > >Dear Mr. Ross, > > >In reading down your web page: http://www.friesian.com/quanta.htm#note-3, I >came across the following: > >Consistency, however, is not always possible. Although the beauty of the >metric system is its foundation on decimal values, which has sold it to >every country in the world except the United States, and some other >oddballs -- though even American customary units are officially defined in >metric terms -- some customary units and strange usages have been retained >or crept in for convenience. Most importantly, the systematization of >decimal counting failed to anticipate the binary basis of modern computer >technology. The powers of 2 now rival the powers of 10, and even metric >prefixes have been corrupted. Thus, when the unit "kilobyte" ("kB" or just >"K") is used, it does not really mean 1000 bytes of information. It means >1024 bytes, i.e. 210. A "megabyte" ("MB" or "Meg") is not 1,000,000 bytes, >but 1,048,576 bytes, i.e. 1024 x 1024 or 220. > > > >The information stated above is no longer correct. In fact it has never >been. The SI prefixes have always had a decimal meaning and never a binary >meaning that was officially or legally sanctioned. The BIPM and CGPM do >not recognise alternate meanings to the SI prefixes. If it is done, it is >done without the authority of the standards bodies. > >In not all cases in computer technology have the SI prefixes been corrupted >to mean powers of 2. In the case of hard drives, the prefixes retain their >SI meaning. Thus a 10 GB hard drive contains 10 x 10^9 B and not 10 x 2^30 >B. The abuse of the prefixes in computer technology is inconsistent. > >To address the need for powers of 2 prefixes, the IEC in 1998 authorised a >new set of prefixes to handle the powers of 2. These prefixes are similar >to the SI prefixes, but are meant to be used when expressing capacity in >powers of 2. The binary prefixes use the SI prefixes, kilo, mega, giga, >tera, etc and contract them with the word "binary" to come up with Kibi, >Mibi, Gibi, Tibi, etc. These prefixes are only to be combined with the >units bit and byte (B). Thus a Kibibyte is 2^10 B, a Mibibyte is 2^20 B, a >Gibibyte is 2^30 B, etc. The symbols are Ki, MI, Gi, etc. > > > >For more information on these prefixes, visit the site: >http://physics.nist.gov/cuu/Units/binary.html > > > >Also note that the unit Angstrom is not a proper SI unit and is deprecated. > It is obsolete and is fast disappearing. In fact, I never hear or see it >anymore, except in something old. The proper replacement is the nanometre >equal to 10^-9 m. > > > >Please review the information and update your webpage accordingly. > > > >Best Regards, > > > >John > d _________________________________________________________________ Werden Sie Mitglied bei MSN Hotmail, dem gr��ten E-Mail-Service der Welt. http://www.hotmail.com/de
