> > Obviously the disk access itself must be sector aligned and the total
> > length must be a multiple of the sector length, but there shouldn't be
> > any restrictions on the data buffers.
>
> But there are. Many controllers just break down and corrupt things
> silently if you don't align the data buffers (Jeff Merkey found this
> by accident when he started generating unaligned IOs within page
> boundaries in his NWFS code). And a lot of controllers simply cannot
> break a sector dma over a page boundary (at least not without some
> form of IOMMU remapping).
so we are putting workarounds for hardware bugs into the design?
Ingo
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