GNU bug report logs - #15056
Please indicate the meaning of block sizes in filesystem information

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Package: coreutils;

Reported by: Filipus Klutiero <chealer <at> gmail.com>

Date: Fri, 9 Aug 2013 04:36:02 UTC

Severity: wishlist

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Report forwarded to bug-coreutils <at> gnu.org:
bug#15056; Package coreutils. (Fri, 09 Aug 2013 04:36:02 GMT) Full text and rfc822 format available.

Acknowledgement sent to Filipus Klutiero <chealer <at> gmail.com>:
New bug report received and forwarded. Copy sent to bug-coreutils <at> gnu.org. (Fri, 09 Aug 2013 04:36:02 GMT) Full text and rfc822 format available.

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From: Filipus Klutiero <chealer <at> gmail.com>
To: bug-coreutils <at> gnu.org
Subject: Please indicate the meaning of block sizes in filesystem information
Date: Fri, 09 Aug 2013 00:35:10 -0400
[Message part 1 (text/plain, inline)]
Severity: wishlist

stat -f provides information on the filesystem, including block sizes:
> Block size: 4096       Fundamental block size: 4096
The unit used in unfortunately not specified. Considering the fdisk output I get...
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
... I guess bits are the unit.

Note that the first measure ("Block size") is quite ambiguous. http://www.hitachi.co.jp/Prod/comp/soft1/manual/jp1en/d3R4900e/PCAU0135.HTM has some block size terminology which might help (if that's indeed the type of block we mean):
> The basic block size (FFBS: Fundamental Filesystem Block Size) used in the field table of this record is the allocation unit used during file system creation. The number of blocks that corresponds to the basic block size is called the /basic block count/. The logical block size (PFBS: Preferred Filesystem Block Size) is the allocation unit used during input/output operations. The number of blocks that corresponds to the logical block size is called the /logical block count/.
-- 
Filipus Klutiero
http://www.philippecloutier.com

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Information forwarded to bug-coreutils <at> gnu.org:
bug#15056; Package coreutils. (Fri, 09 Aug 2013 04:54:01 GMT) Full text and rfc822 format available.

Message #8 received at 15056 <at> debbugs.gnu.org (full text, mbox):

From: Pádraig Brady <P <at> draigBrady.com>
To: Filipus Klutiero <chealer <at> gmail.com>
Cc: 15056 <at> debbugs.gnu.org
Subject: Re: bug#15056: Please indicate the meaning of block sizes in
 filesystem information
Date: Fri, 09 Aug 2013 05:53:32 +0100
On 08/09/2013 05:35 AM, Filipus Klutiero wrote:
> Severity: wishlist
> 
> stat -f provides information on the filesystem, including block sizes:
>> Block size: 4096       Fundamental block size: 4096
> The unit used in unfortunately not specified. Considering the fdisk output I get...
>> Sector size (logical/physical): 512 bytes / 512 bytes
>> I/O size (minimum/optimal): 512 bytes / 512 bytes
> ... I guess bits are the unit.

always bytes

There are generally 3 layers of block sizes between the file system and device:

1. physical	defined by the hardware device
2. logical		the smallest addressable unit used for the device
3. file system	ditto for the file system

So your numbers above are not the same item being represented.
They're all in bytes and represent different values 1,2,3 above

thanks,
Pádraig.




This bug report was last modified 12 years and 11 days ago.

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