From owner-freebsd-questions@freebsd.org Thu Mar 16 20:12:05 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 04656D0FC70 for ; Thu, 16 Mar 2017 20:12:05 +0000 (UTC) (envelope-from ephaeton@gmx.net) Received: from mout.gmx.net (mout.gmx.net [212.227.17.21]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "mout.gmx.net", Issuer "TeleSec ServerPass DE-2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 576451B73 for ; Thu, 16 Mar 2017 20:12:03 +0000 (UTC) (envelope-from ephaeton@gmx.net) Received: from [10.0.0.2] ([194.118.106.252]) by mail.gmx.com (mrgmx103 [212.227.17.168]) with ESMTPSA (Nemesis) id 0LlDx4-1cFpQg28lK-00azKs for ; Thu, 16 Mar 2017 21:11:56 +0100 Subject: Re: bootable ext. USB SSD for backup To: freebsd-questions@freebsd.org References: <20170316194612.GA1748@c720-r314251> <33953.128.135.52.6.1489694167.squirrel@cosmo.uchicago.edu> From: "Martin S. Weber" Message-ID: <92024f3c-2ab3-1741-97de-36455ca56b7e@gmx.net> Date: Thu, 16 Mar 2017 21:11:53 +0100 User-Agent: Mozilla/5.0 (X11; Linux armv7l; rv:45.0) Gecko/20100101 Icedove/45.5.1 MIME-Version: 1.0 In-Reply-To: <33953.128.135.52.6.1489694167.squirrel@cosmo.uchicago.edu> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Provags-ID: V03:K0:9wNmSSFH/9YGtodNvnfIXDDSgXs8eYbc/n9GK2FnWXWbulwEPgX XeYFlgR5sZUh27AjBA9U09uRQkHrwY1podoojbfQZl7E9QJCUgWcHsowDo1IUNpAfG6lZck GB06OgoDfnswBJSsyEjtXmnQTOi2xSRUiJmt9NWy0479jYF6ofP4VZfIG9P0nGEaqA7hMKw ebAr9VwapftAzCmNmj4kw== X-UI-Out-Filterresults: notjunk:1;V01:K0:Sk0fVub/af4=:gpd6JoRkS5tC/gOkv+IWbU GvqNFo4TVaqcJvQSghL/DoUtKZwvS9snmddS7QWpMjLbal/POfQtjVfKU6Wfqbq2eZfuSV2yM 5Cfq3njdAmYpqZTSvPEbNYRPDs79ti70zpJzLqiBt2B1EbhanYMxj3s9L/sEiE4EI/wFcmp4F 1JJbyr+xkexQTH205+S8Q7ODyzY2y2NcccKycokvNZxtZi4DtqMkWdHZQw2aKnFOJRXo8T0Mo PvcEmClmhY8QUYhoiZkRcFOz3AEFjey+ZwTuqnQh6GY3Vleun0xZjXM6BFO/d8rr5wum1G/rO SEiCtXQfl7AfXkxFjYNcFHiu8c0iCZLLEpORGIEiCP2+GTLRZVj7BME3bxhRTaNzsfwdnKA1y Fu5+WE4rEDsTq7NFH81yIbBAAbYRCDJsDf3ACz/KJfqvH2UY2CencloMA5NGqdvrt5lKCC1cq +dU4Y8//7uAShYodhNE6ebiA8zC3Nh0awWyODSll0JmzTFzSBZcCxxFs5aHmpeecBnZd7Zm2A L2sP6TFPK+Qjugi4Pu5l/Ae/COPPcuprqGhd1mmMP1dFtUfddyHiXvdRp10XHqfGFmJrMIm/3 FPzw0CI+tFkRFhUn2lu2gXX7qo+/jB7kZoUP9rFwE/AUasyTdK5mmRbmlOyBPwDWF6dmQgsOv 2I771HOLCQ34LoHMnehWl5XH3PoqXaZZ7s/LC3jM0I3bB/UOhCOlpSqaK+R+0XblUYXJVvFZz H/evB0Ok3MuJQ6sxMBULxzNfw2ELhVzr8rQ1FnHojpizJgPGTusMXSLNVX1M08WUSmGrArvaJ 0em/VWo 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 20:12:05 -0000 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), 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