From owner-freebsd-questions@freebsd.org Thu Mar 16 20:19:32 2017 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id D4D29D0F07E for ; Thu, 16 Mar 2017 20:19:32 +0000 (UTC) (envelope-from galtsev@kicp.uchicago.edu) Received: from cosmo.uchicago.edu (cosmo.uchicago.edu [128.135.20.71]) by mx1.freebsd.org (Postfix) with ESMTP id B4ED11EB8 for ; Thu, 16 Mar 2017 20:19:32 +0000 (UTC) (envelope-from galtsev@kicp.uchicago.edu) Received: by cosmo.uchicago.edu (Postfix, from userid 48) id 5DC86CB8CA2; Thu, 16 Mar 2017 15:19:31 -0500 (CDT) Received: from 128.135.52.6 (SquirrelMail authenticated user valeri) by cosmo.uchicago.edu with HTTP; Thu, 16 Mar 2017 15:19:31 -0500 (CDT) Message-ID: <39513.128.135.52.6.1489695571.squirrel@cosmo.uchicago.edu> In-Reply-To: <92024f3c-2ab3-1741-97de-36455ca56b7e@gmx.net> References: <20170316194612.GA1748@c720-r314251> <33953.128.135.52.6.1489694167.squirrel@cosmo.uchicago.edu> <92024f3c-2ab3-1741-97de-36455ca56b7e@gmx.net> Date: Thu, 16 Mar 2017 15:19:31 -0500 (CDT) Subject: Re: bootable ext. USB SSD for backup From: "Valeri Galtsev" To: "Martin S. Weber" Cc: freebsd-questions@freebsd.org Reply-To: galtsev@kicp.uchicago.edu User-Agent: SquirrelMail/1.4.8-5.el5.centos.7 MIME-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 16 Mar 2017 20:19:32 -0000 On Thu, March 16, 2017 3:11 pm, Martin S. Weber wrote: > On 03/16/17 20:56, Valeri Galtsev wrote: >> >> On Thu, March 16, 2017 2:46 pm, Matthias Apitz wrote: > >> (...) >>> Mar 16 19:36:54 c720-r314251 kernel: da0: 953869MB (1953525164 512 byte >>> sectors) >>> Mar 16 19:36:54 c720-r314251 kernel: da0: quirks=0x2 >>> >>> Ofc it has not the promised 1 TB volume, just only 953869 MB, i.e. only >>> 1 Marketing-TB; >> >> It may have to do with counting by power of 10 instead of power of 2 >> (Not >> exactly correct, but close). Which remind me an old joke: >> >> Do you know the difference between junior programmer and senior >> programmer? >> >> Junior programmer faithfully thinks that one kilobyte is exactly 1000 >> bytes. >> >> Senior programmer faithfully thinks that one kilogram is exactly 1024 >> grams. >> > > Well, there's a proper SI prefix for powers of two, which for your joke, > Valeri, is "kibi" (2^10), I know, I know. The joke was meant to be consumed orally, not in a written form. And it is so old that at the time I've heard it for the first time, there were no Ki- Mi- prefixes (and we didn't dream about Gi then). Or probably I was so ignorant then... Valeri > and for Matthias is "Mibi", "Gibi" > respectively "Tebi"; they are abbreviated as KiB, MiB, GiB and TiB, > respectively (when applied to bytes). So the junior programmer is > actually correct, and the senior programmer should know a kibigram has > 1024 grams. It doesn't help that FreeBSD isn't using proper prefixes > for printouts itself. > > Toshiba says this thing has 1 TB, which is 10^12 bytes, which is (10^12) > / 512 512-byte units, or, in other words, 1953125000 512 byte units. > Contrast that with the reported 1953525164 512 byte units the drive > actually lets you access. Toshiba is clearly underselling the disk. > > /anal mode off > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to > "freebsd-questions-unsubscribe@freebsd.org" > ++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++