[parted-devel] Failure with O_DIRECT

[Leslie P. Polzer]

>> And two other questions:
>> 1. While phys_sector_size is pretty clear, what does sector_size
>> (logical sector size) in PedDevice represent?  Could it be so that
>> this variable should be the same as the block size of the
>> filesystem?
>
> I wondered the same thing, and concluded "Yes", but
> maybe Andrew or Leslie (Cc'd) can confirm that.
> If so, I'll document it, so no one else has to wonder :)

phys_sector_size is the drive's physical (internal) sector size, a thing
reported since ATAPI8 IIRC (see http://bigsector.org/ for information on this
topic). Alignment need not be aligned to this, but the should, to avoid
severe speed penalties.  Parted seems to be the only partitioning tool
to support this at the moment.

sector_size is the drive's logical sector size.

Both of them have nothing to do with the file system's block size;
the three constraints are imposed separately on alignment calculations.

  Leslie