Re: RES: AS2105-based enclosure size issues with >2TB HDDs

Alan Stern
2014-08-25T19:33:50Z

On Mon, 25 Aug 2014, Alfredo Dal Ava Junior wrote:

> On Mon, 25 Aug 2014, Alan Stern wrote:
> >
> > Don't forget that lots of disks go crazy if you try to read from a nonexistent
> > block, that is, one beyond the end of the disk.
> > IMO, this bug cannot be worked around in any reasonable manner. The
> > device simply cannot handle disks larger than 2 TB.
>
>
> This device works well on Windows 7 if HDD is already partitioned.
> Sounds like Win7 gnores the READ_CAPACITY value on a partitioned HDD.
> It shows 4TB on disk manager, but will fall back to 1.8TB if I remove
> the partition.

That's right. I don't know why Windows behaves that way.

> Could we do the same? Would be possible to signalize to upper layers
> that capacity is not accurate (or return zero) on this device, and
> tell GPT handlers to bypass it's partition_size vs disk size
> consistency check?

There is no way to do this, as far as I know. But I'm not an expert in
this area. Maybe you can figure out a way to add this capability.

(But then what happens if the size stored in the partition table really
is larger than the disk's capacity?)

Alan Stern