> From the system's point of view, there is no difference in reliability
> between doing a single sector transfer and a multi-sector transfer
> except for the size of the retry. Since retries do not occur very often
> nobody really cares how big the retry is. Since there is a huge
> performance gain doing multi-sector transfers, that is what the
> system does.
>
Thanks. It seems to me that for a filesystem, a block (or a fragment) is
the unit of I/O. Even if a single byte is modified, an entire block
probably consisting of multiple sectors must be written back to the disk.
As you said, there is no differnce whether we write this block one sector
at a time or in a single transfer. If so, I wonder whether the atomicity
of a sector I/O required by a directory file is necessary any more.
-Zhihui
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