Re: tools support for non-512 byte sector sizes

[Ric Wheeler]

Theodore Tso wrote:
> On Wed, Jul 30, 2008 at 12:29:22PM -0500, Matt Domsch wrote:
>   
> > 2) those that report a 512-byte sector size, but are really a
> >    4096-byte size, and the drive does the conversions and
> >    read/modify/write.  T10 and T13 are looking to add commands to
> >    expose this different underlying physical sector size so the OS
> >    could be aware of it.  This is primarily being driven to mitigate
> >    any problems that may happen with "legacy" OSs that are not aware
> >    of the difference.
> >     
>
> As usual, the biggest problem will be "legacy" userspace.  For
> example, most partition tools are still generating legacy partition
> tables that look like this:
>
> Disk /dev/sda: 255 heads, 63 sectors, 38913 cylinders
>
> Nr AF  Hd Sec  Cyl  Hd Sec  Cyl     Start      Size ID
>  1 80   1   1    0 254  63  121         63    1959867 83
>  2 00   0   1  122 254  63  619    1959930    8000370 82
>  3 00   0   1  620 254  63 1023    9960300  615177045 05
>  4 00   0   0    0   0   0    0          0          0 00
>  5 00   1   1  620 254  63 1023         63  615176982 8e
>
> Note the starting sector# for the first partition.....
>
> 						- Ted
>   
If I remember correctly, the MS Vista new alignment for data partitions 
is on a 0 offset, 1MB aligned boundary. The support for 4096 byte 
sectors is only for data partitions (not boot).

Array vendors, who consume a fair amount of drives, are most likely more 
friendly to native 4k drives. The big fear from disk vendors is getting 
a wave of returns from Best Buy, etc when people go and plug in a new, 
native 4k drive into an old box....

ric

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