From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Robinson Subject: Re: Adding a smaller drive Date: Sun, 05 Jul 2009 23:12:47 +0100 Message-ID: <4A51255F.1020308@anonymous.org.uk> References: <20090705220252458.BCFJ19903@cdptpa-omta03.mail.rr.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20090705220252458.BCFJ19903@cdptpa-omta03.mail.rr.com> Sender: linux-raid-owner@vger.kernel.org To: lrhorer@satx.rr.com Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 05/07/2009 23:03, Leslie Rhorer wrote: [...] >> I think I might take to doing that too, making my partitions/arrays >> multiples of 1,000,000,000 bytes (a drive maker's 1GB) where possible, >> just to be sure :-) > > Well, that's not quite possible, of course, since sectors are > usually 512 bytes, and 1E9 is not a multiple of 512. Indeed, that's where > this whole situation is ridiculous. For drive manufacturers to even consider > using GB as a measuring basis is ludicrous. If sectors were 1000 bytes, and > if computer registers were base 10, it would be an entirely different > matter, but the fact is the sector size is 2^9 and all the register > boundaries are going to be multiples of 2, not 10. But 10^9 is divisible by 512: 10^9 = (2*5)^9 = 2^9 * 5^9. There are therefore 1953125 512-byte sectors in 1 drive maker's GB. Cheers, John.