On 03/08/2010 12:19 PM, Martin K. Petersen wrote: >>>>>> "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. > Obviously. However, larger physical storage unit sizes -- 4K for spinning media, but frequently much larger for flash, for example -- is already in wide use, and having a huge mishmash of logical block sizes isn't going to work very well. > 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. I personally suspect that that is the way it is going to go, rather than trying to change the software ecosystem to a different logical block size. It has been tried in the past and failed, with the sole exception of CD-ROMs, pretty much. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
