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Date: Mon, 12 Nov 2012 22:42:25 -0500
From: Vladislav Bolkhovitin <vst@vlnb.net>
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CC: "Theodore Ts'o" <tytso@mit.edu>,
        General Discussion of SQLite Database 
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Subject: Re: [sqlite] light weight write barriers
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杨苏立 Yang Su Li, on 11/10/2012 11:25 PM wrote:
>>  SATA's Native Command
>>> Queuing (NCQ) is not equivalent; this allows the drive to reorder
>>> requests (in particular read requests) so they can be serviced more
>>> efficiently, but it does *not* allow the OS to specify a partial,
>>> relative ordering of requests.
>>>
>>
>> And so? If SATA can't do it, does it mean that nobody else can't do it
>> too? I know a plenty of non-SATA devices, which can do the ordering
>> requirements you need.
>>
>
> I would be very much interested in what kind of device support this kind of
> "topological order", and in what settings they are typically used.
>
> Does modern flash/SSD (esp. which are used on smartphones) support this?
>
> If you could point me to some information about this, that would be very
> much appreciated.

I don't think storage in smartphone can support such advanced functionality, 
because it tends to be the cheapest, hence the simplest.

But many modern Enterprise SAS drives can do it, because for those customers 
performance is the key requirement. Unfortunately, I'm not sure I can name exact 
brands and models, because I had my knowledge from NDA'ed docs, so this info can 
be also NDA'ed.

Vlad
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