Re: Is there a reliable way to ID a SSD?

[Jeff Garzik <jeff@garzik.org>]

On 01/06/2011 01:40 PM, Greg Freemyer wrote:
> (resend, sorry for the duplicate)
>
> Jeff,
>
> As the maintainer, can you provide direction as to how quirks should
> be maintained for the rotating disk flag (as reflected in
> /sys/block/sda/queue/rotational).
>
> There is Bart's patch, Peter's patch, and Martin says it can be
> overridden from userspace (I'm not sure which tool,  nor do I know if
> there is already a userspace quirks table to add to.).
>
> Bart's atang PATCH: http://marc.info/?l=linux-ide&m=126677421807814&w=2
>
> Peter's patch: http://www.spinics.net/lists/linux-ide/msg38944.html

There are a long list of non-rotational devices that were produced 
before the ATA standard grew a standard method of reporting that device 
attribute.

That implies any approach individually listing products will create a 
very, very long horkage list containing all ATA flash drives that anyone 
ever produced.

Alternately, scanning for the "SSD" string does not seem very useful, 
because it will only match a tiny minority of first-run products that 
(a) call themselves "SSD" in marketing literature but (b) do not 
indicate proper rotational attributes in the IDENTIFY page.  Because 
while non-rotational products have been around for a very long time, 
"SSDs" as they are a currently known are new.

It seems like a project to retroactively identify ATA non-rotational 
products will be long and on-going, and would be better suited to a 
userspace package such as Tejun's storage-fixup: 
http://git.kernel.org/?p=linux/kernel/git/tj/storage-fixup.git

	Jeff