From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Arlott Subject: Re: [PATCH] scsi/sd: Fix capacity output to show MB/GB/TB/... Date: Sun, 31 Aug 2008 16:08:43 +0100 Message-ID: <48BAB3FB.1050809@simon.arlott.org.uk> References: <48B9546B.4010004@simon.arlott.org.uk> <1220117091.3615.3.camel@localhost.localdomain> <20080830174516.GD1239@parisc-linux.org> <48B9B552.8060406@simon.arlott.org.uk> <48B9B588.7060709@simon.arlott.org.uk> <1220147947.3615.18.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from proxima.lp0.eu ([85.158.45.36]:52190 "EHLO proxima.lp0.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751085AbYHaPIr (ORCPT ); Sun, 31 Aug 2008 11:08:47 -0400 In-Reply-To: <1220147947.3615.18.camel@localhost.localdomain> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: James Bottomley Cc: Matthew Wilcox , Linux Kernel Mailing List , linux-scsi On 31/08/08 02:59, James Bottomley wrote: > On Sat, 2008-08-30 at 22:03 +0100, Simon Arlott wrote: >> The capacity printk'd in bytes is divided by 1000000, >> whereas 1048576 would be more consistent with the rest >> of the OS and disk-related utilities ('df' etc.). >> >> This change replaces the (sz - (sz/625 - 974))/1950 >> calculation with a simple right shift to output with >> five significant digits the capacity in KB, MB, GB, TB, >> PB, or EB. Anything beyond this becomes too large... > > Well, still needs to be dividing by 1000 not 1024 for SCSI and ATA. > However, I'm afraid it needs to be a bit more sophisticated: for > instance, under these calculations, a 1.75TB disk will show up as 1TB. > Thus, I think we need to print the capacity to 3 significant figures to > cope with this case. Actually it'll show up as 1629GB, as my patch shows up to 5 digits (not five significant digits, which would require outputting a non-integer value). Isn't outputting "1.75" unnecessarily complicated, and "1750" would work better? -- Simon Arlott