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From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Simon Arlott <simon@fire.lp0.eu>
Cc: Matthew Wilcox <matthew@wil.cx>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-scsi <linux-scsi@vger.kernel.org>
Subject: Re: [PATCH] scsi/sd: Fix capacity output to show MB/GB/TB/...
Date: Sat, 30 Aug 2008 20:59:07 -0500	[thread overview]
Message-ID: <1220147947.3615.18.camel@localhost.localdomain> (raw)
In-Reply-To: <48B9B588.7060709@simon.arlott.org.uk>

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.

James



  reply	other threads:[~2008-08-31  1:59 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-30 14:08 [PATCH] scsi/sd: Fix size output in MB Simon Arlott
2008-08-30 17:24 ` James Bottomley
2008-08-30 17:45   ` Matthew Wilcox
2008-08-30 20:59     ` Pierre Ossman
2008-08-30 21:45       ` James Bottomley
2008-08-30 22:13         ` Pierre Ossman
2008-08-30 22:24           ` Simon Arlott
2008-08-30 22:36           ` Matthew Wilcox
2008-08-30 21:02     ` Simon Arlott
2008-08-30 21:03       ` [PATCH] scsi/sd: Fix capacity output to show MB/GB/TB/ Simon Arlott
2008-08-31  1:59         ` James Bottomley [this message]
2008-08-31  2:54           ` Matthew Wilcox
2008-08-31 14:25             ` Ingo Oeser
2008-08-31 15:04               ` Simon Arlott
2008-08-31 15:08             ` James Bottomley
2008-08-31 15:13               ` [PATCH 1/2] lib: add generic helper to print sizes rounded to the correct SI range James Bottomley
2008-08-31 15:20                 ` Simon Arlott
2008-08-31 15:41                   ` James Bottomley
2008-08-31 15:51                 ` Matthew Wilcox
2008-08-31 18:54                 ` [PATCH] mmc_block: use generic helper to print capacities Pierre Ossman
2008-09-05 20:09                   ` James Bottomley
2008-09-05 20:52                     ` Pierre Ossman
2008-09-05 21:03                       ` James Bottomley
2008-09-06  8:57                         ` Pierre Ossman
2008-09-03  3:39                 ` [PATCH 1/2] lib: add generic helper to print sizes rounded to the correct SI range Andrew Morton
2008-09-03 14:32                   ` James Bottomley
2008-09-03 15:58                     ` Andrew Morton
2008-08-31 15:15               ` [PATCH 2/2] sd: use generic helper to print capacities in both binary and SI James Bottomley
2008-08-31 15:08           ` [PATCH] scsi/sd: Fix capacity output to show MB/GB/TB/ Simon Arlott
2008-08-30 21:57       ` [PATCH] scsi/sd: Fix size output in MB Matthew Wilcox
2008-08-30 22:22         ` Simon Arlott
2008-08-31 12:27         ` James Smart

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