Re: Large disk drives

[Alan Stern <stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public.gmane.org>]

On Tue, 4 Nov 2014, James Bottomley wrote:

> On Mon, 2014-11-03 at 16:06 -0500, Dale R. Worley wrote:
> > Was there any resolution as to how large disk drives would be handled
> > if their interface did not support the "capacity" request that would
> > tell how large they were?
> 
> Realistically no ... unless someone comes up with a reliable heuristic
> to give us the size.

I posted a patch to allow the user to override the reported capacity:

	http://marc.info/?l=linux-scsi&m=140993840113445&w=2

Nobody responded to it.

> > Unfortunately, such devices work OK with Windows (since Windows trusts
> > what the partition table says), you can't just say to the salesperson
> > "It has to work on drives over 3 TB."
> 
> This is a stopgap: your 3TB drive can be guessed as the 16 bit capacity
> plus 2TB, but the same won't happen for a 5TB device.  Believing the
> partition table gives us a chicken and egg problem because something
> still has to get the partition table on to the device.
> 
> I don't think "don't buy something that doesn't work" is a hugely
> unreasonable response to this.

The problem is knowing beforehand whether it will work.  Once you buy 
the device and can test it, returning it is annoying and time-consuming 
at best.

Alan Stern

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