Messages in this thread | | | Date | Tue, 21 Aug 2001 15:55:55 -0400 | From | Nick DeClario <> | Subject | Determining maximum partition size on a hard disk |
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I am trying to calculate the maximum size a partition can be on a hard drive and I ran into some problems I don't fully understand.
First I found that the maximum size of the drive Linux reports is not the maximum size I get when I calculate it from the drives geometry. Secondly, the total drive space reported by linux is not the amount available for the maximum partition.
For example, I have a 4.3Gb disk. The drives geometry is 525 cylinders, 255 heads and 63 sectors (525 * 255 * 63 * 512 = 4318272000 or 4.318Gb).
This is an IDE disk so I found in /proc/ide/hdx/capacity a block size 8439184, which when divided by 2048 is 4120.7, ~200Mb less than what I calculated as the disk size.
Finally, using a program such as fdisk or sfdisk I create a partition manually to be the maximum amount allowed, which turns out to be 4217041 blocks, or, when divided by 1024 is 4118.2.
I assume that the difference between the maximum size that linux reports and the maximum partition size is due to linux leaving room for a MBR and such. If so how do I go about calculating this? Also why does the size of the drive I calculate out by using the drives geometry differ so much from the amount Linux reports? I thought maybe Linux set 1MB=1000k but that doesn't seem to case.
Any information or a push in the right direction would be appreciated, thanks!
Regards, -Nick DeClario - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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