Re: ATA 4 KiB sector issues.

From: Martin K. Petersen
Date: Mon Mar 08 2010 - 15:22:20 EST


>>>>> "hpa" == H Peter Anvin <hpa@xxxxxxxxx> writes:

hpa> On the flipside, though, there really is very little net benefit to
hpa> 4K as opposed to 512 byte logical sectors: the additional protocol
hpa> overhead is relatively minimal, and as long as writes are aligned
hpa> full blocks, there shouldn't be any additional overhead on either
hpa> the OS or the drive side. On the plus side, you get full
hpa> compatibility with the existing software stack. The equation
hpa> really seems rather simple.

4KB sectors are not a win for anybody except the drive vendors.

There is a push in the industry right now to keep the 512-byte logical
blocks forever. The first step would be to report misaligned accesses
or accesses that are not a multiple of the physical block size. Second
step would be to eventually reject any write that's not a properly
aligned multiple of the physical block size.

--
Martin K. Petersen Oracle Linux Engineering
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