Re: [OT] Hard Drive Energy Not Worth Conserving drives?
> Read the ATA and SCSI specifications. Or ask on either mailing list.
> In short, the drive presents its LBA addressing based on 512B sectors.
> The kernel can't choose to ignore that--it's stuck with it. Since the
> drive is presenting LBA based on 512B sectors, there is no way the
> kernel can address LBA based on 4K sectors.
I don't follow: what prevents the kernel from telling the higher-up
tools that the drive uses 4KB sectors (or 72KB sectors for that matter)?
>> In any case, the issue is probably not really in the kernel but in the
>> filesystems and partitioning tools: all that's really needed to use the
> The current "problem" with the hybrid drives is that the partitioning
> utilities don't automatically align partitions on the underlying 4k
> sector boundaries.
I'm glad we agree.
>> Indeed, and for that reason 4KB physical blocks wouldn't cause
>> additional disk space usage.
> The space savings with 4KB sectors has nothing to do with file systems
> or user data.
I was talking about the space usage increase incurred from the use of
≥4KB blocks in the FS, if we assume that the FS uses the underlying HD
block size as a lower-limit of its own block size.
> This is the ONLY reason these 4KB sector drives were developed: more
> actual end user space on the drive.
That's a different topic, but an interesting one as well: the gain seems
small (e.g. WD has/had two Green 2TB drives, one using 4KB sectors and
the other using good'ol 512B sectors, and this using apparently the
same underlying head/drive technology, so it seems the gain, if any, was
too small to make it to the end user).
So why does WD do that?
Stefan
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