Re: Bug#294206: stat(1) unclear about block size

[James Youngman]

On Tue, Feb 08, 2005 at 02:42:09PM +0100, Jeroen van Wolffelaar wrote:
> Package: coreutils
> Version: 5.2.1-2
> 
>   %s   Optimal transfer block size
> $
> 
> 'Optimal transfer block size', I have the suspection that %s IS the
> blocksize of the filesystem, which should be used in a number of other
> parameters in order to translate number of blocks into number of bytes.
> 
> Is that correct?

No.    The POSIX standard (in a non-normative section) says :-

| The unit for the st_blocks member of the stat structure is not defined
| within IEEE Std 1003.1-2001. In some implementations it is 512
| bytes. It may differ on a file system basis. There is no correlation
| between values of the st_blocks and st_blksize, and the f_bsize (from
| <sys/statvfs.h>) structure members.
| 
| Traditionally, some implementations defined the multiplier for
| st_blocks in <sys/param.h> as the symbol DEV_BSIZE.

I think almost all systems use 512 byte units.

James.