It is said that the granularity of disk I/O is a sector. I read a little
bit of the source code isa/wd.c, which I think is the driver of IDE disks.
I find out that the disk can perform multi-block I/O sometimes. Does this
mean the granularity of disk I/O can be multi-sector? If the disk can
perform DMA, what is the usual DMA size? Is the granularity the DMA size
in this case?
If a buffer cache is larger than one sector, it should be split into
sectors before I/O. If an I/O on a buffer fails, can we tell which sector
within that buffer fails?
I am confused with these things and it is probably that my questions are
confusing too.
Any help or hints are appreciated.
-Zhihui
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