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IDE or AHCI ?

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  IDE or AHCI ? Lynn McGuire <lmc@winsim.com> - 2012-01-03 12:30 -0600
    Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-03 21:05 +0000
      Re: IDE or AHCI ? "arno fucker" <af@arnofucker.com> - 2012-01-04 12:41 +1100
    Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-04 12:58 +1100
    Re: IDE or AHCI ? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2012-01-04 00:07 -0500
      Re: IDE or AHCI ? David Brown <david@westcontrol.removethisbit.com> - 2012-01-04 08:53 +0100
        Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-04 20:32 +1100
          Re: IDE or AHCI ? David Brown <david@westcontrol.removethisbit.com> - 2012-01-04 14:44 +0100
            Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-05 07:37 +1100
              Re: IDE or AHCI ? David Brown <david.brown@removethis.hesbynett.no> - 2012-01-04 22:56 +0100
                Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-05 09:48 +1100
                Re: IDE or AHCI ? Ed Light <nobody@nobody.there> - 2012-01-04 21:40 -0800
                Re: IDE or AHCI ? Mike Tomlinson <mike@jasper.org.uk> - 2012-01-05 05:37 +0000
                  Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-05 17:37 +1100
        Re: IDE or AHCI ? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2012-01-04 09:29 -0500
          Re: IDE or AHCI ? David Brown <david@westcontrol.removethisbit.com> - 2012-01-04 16:04 +0100
            Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-04 19:19 +0000
              Re: IDE or AHCI ? David Brown <david.brown@removethis.hesbynett.no> - 2012-01-04 23:14 +0100
                Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-05 08:47 +0000
            Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-05 07:51 +1100
          Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-04 19:16 +0000
          Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-05 07:41 +1100
            Re: IDE or AHCI ? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2012-01-05 14:44 -0500
              Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-06 17:35 +1100
                Re: IDE or AHCI ? Krypsis <krypsis@optusnet.com.au> - 2012-01-07 00:05 +1100
                  Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-06 20:04 +0000
                    Re: IDE or AHCI ? Mike Tomlinson <mike@jasper.org.uk> - 2012-01-06 21:13 +0000
                      Re: IDE or AHCI ? cjt <cheljuba@prodigy.net> - 2012-01-06 20:42 -0600
                      Re: IDE or AHCI ? David Brown <david.brown@removethis.hesbynett.no> - 2012-01-07 13:48 +0100
                        Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-07 14:09 +0000
                        Re: IDE or AHCI ? Mike Tomlinson <mike@jasper.org.uk> - 2012-01-07 14:36 +0000
                          Re: IDE or AHCI ? Krypsis <krypsis@optusnet.com.au> - 2012-01-08 02:11 +1100
                            Re: IDE or AHCI ? Mike Tomlinson <mike@jasper.org.uk> - 2012-01-09 12:06 +0000
                              Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-09 16:27 +0000
                                Re: IDE or AHCI ? Mike Tomlinson <mike@jasper.org.uk> - 2012-01-09 17:36 +0000
                                Re: IDE or AHCI ? Mike Tomlinson <mike@jasper.org.uk> - 2012-01-09 17:41 +0000
                                  Re: IDE or AHCI ? Winniethepooh@100acrewoods.net (GMAN) - 2012-01-09 19:07 +0000
                                    Re: IDE or AHCI ? David Brown <david.brown@removethis.hesbynett.no> - 2012-01-09 20:12 +0100
                                    Re: IDE or AHCI ? Mike Tomlinson <mike@jasper.org.uk> - 2012-01-09 21:00 +0000
                              Re: IDE or AHCI ? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2012-01-09 11:31 -0500
                          Re: IDE or AHCI ? David Brown <david.brown@removethis.hesbynett.no> - 2012-01-07 17:10 +0100
                            Re: IDE or AHCI ? Mike Tomlinson <mike@jasper.org.uk> - 2012-01-10 14:18 +0000
                    Re: IDE or AHCI ? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2012-01-09 11:23 -0500
                      Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-09 16:30 +0000
                      Re: IDE or AHCI ? David Brown <david.brown@removethis.hesbynett.no> - 2012-01-09 20:16 +0100
                      Re: IDE or AHCI ? cjt <cheljuba@prodigy.net> - 2012-01-09 17:13 -0600
                  Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-07 08:11 +1100
                    Re: IDE or AHCI ? Krypsis <krypsis@optusnet.com.au> - 2012-01-08 01:23 +1100
                      Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-08 06:43 +1100
                        Re: IDE or AHCI ? JW <none@dev.null> - 2012-01-09 05:23 -0500
                Re: IDE or AHCI ? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2012-01-09 10:24 -0500
                  Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-10 09:34 +1100
                    Re: IDE or AHCI ? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2012-01-09 20:04 -0500
                      Re: IDE or AHCI ? "Rod Speed" <rod.speed.aaa@gmail.com> - 2012-01-10 15:33 +1100
              Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-06 09:48 +0000
                Re: IDE or AHCI ? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2012-01-09 11:35 -0500
                  Re: IDE or AHCI ? David Brown <david.brown@removethis.hesbynett.no> - 2012-01-09 20:23 +0100
                    Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-10 11:31 +0000
                      Re: IDE or AHCI ? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2012-01-20 06:54 -0500
        Re: IDE or AHCI ? Arno <me@privacy.net> - 2012-01-04 19:14 +0000

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#2242 — IDE or AHCI ?

What is the fastest hard drive access method for
Windows 7 x64, IDE or AHCI ?  I have a WD 1 TB
caviar black, a Gigabyte z68xp-ud5 motherboard
and a Intel I3-2500K with 8 GB of ram.

I see these thoughts:
    http://expertester.wordpress.com/2008/07/24/ahci-vs-ide-%E2%80%93-benchmark-advantage/
    http://tweaks.com/windows/44119/improve-sata-hard-disk-performance-convert-from-ide-to-ahci/

Thanks,
Lynn

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#2243

Lynn McGuire <lmc@winsim.com> wrote:
> What is the fastest hard drive access method for
> Windows 7 x64, IDE or AHCI ?  I have a WD 1 TB
> caviar black, a Gigabyte z68xp-ud5 motherboard
> and a Intel I3-2500K with 8 GB of ram.

> I see these thoughts:
>    http://expertester.wordpress.com/2008/07/24/ahci-vs-ide-%E2%80%93-benchmark-advantage/
>    http://tweaks.com/windows/44119/improve-sata-hard-disk-performance-convert-from-ide-to-ahci/

> Thanks,
> Lynn

It should not matter much for speed. AHCI has hotplug, IDE does 
not though. And AHCI dirvers may be newer, improving speed.
Unfortunately even Win 7 has problematic (no?) AHCI support out
of the box and requires drivers. AFAIK this is motsly an issue for 
new installations. Under Linux it does not matter.

Arno
-- 
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@wagner.name
GnuPG:  ID: 1E25338F  FP: 0C30 5782 9D93 F785 E79C  0296 797F 6B50 1E25 338F
----
Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans

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#2246

Arno wrote:
> Lynn McGuire <lmc@winsim.com> wrote:

>> What is the fastest hard drive access method for
>> Windows 7 x64, IDE or AHCI ?  I have a WD 1 TB
>> caviar black, a Gigabyte z68xp-ud5 motherboard
>> and a Intel I3-2500K with 8 GB of ram.

>> I see these thoughts:

>> http://expertester.wordpress.com/2008/07/24/ahci-vs-ide-%E2%80%93-benchmark-advantage/
>> http://tweaks.com/windows/44119/improve-sata-hard-disk-performance-convert-from-ide-to-ahci/

> It should not matter much for speed. AHCI has hotplug, IDE does
> not though. And AHCI dirvers may be newer, improving speed.
> Unfortunately even Win 7 has problematic (no?) AHCI support out
> of the box and requires drivers.

Wrong, as always.

> AFAIK this is motsly an issue for new installations.

Wrong, as always.

> Under Linux it does not matter.

Wrong, as always. The difference isnt huge, but the first set of benchmarks show that the effect is real. 

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#2248

Lynn McGuire wrote:

> What is the fastest hard drive access method for Windows 7 x64, IDE or AHCI ?

There clearly isnt a lot in it give the stats in your first link.

I doubt you'd be able to pick the difference in a proper double blind
trial without being allowed to use a benchmark with normal work.

If you can, with normal work, use the config which gives the best result WITH THAT WORK.

> I have a WD 1 TB caviar black, a Gigabyte z68xp-ud5 motherboard and a Intel I3-2500K with 8 GB of ram.

> I see these thoughts:

> http://expertester.wordpress.com/2008/07/24/ahci-vs-ide-%E2%80%93-benchmark-advantage/
> http://tweaks.com/windows/44119/improve-sata-hard-disk-performance-convert-from-ide-to-ahci/

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#2251

On 03/01/2012 1:30 PM, Lynn McGuire wrote:
> What is the fastest hard drive access method for
> Windows 7 x64, IDE or AHCI ? I have a WD 1 TB
> caviar black, a Gigabyte z68xp-ud5 motherboard
> and a Intel I3-2500K with 8 GB of ram.
>
> I see these thoughts:
> http://expertester.wordpress.com/2008/07/24/ahci-vs-ide-%E2%80%93-benchmark-advantage/
>
> http://tweaks.com/windows/44119/improve-sata-hard-disk-performance-convert-from-ide-to-ahci/

I did the switch to AHCI back in the Windows XP days. At that time it 
was a difficult transition as there were no default AHCI drivers, and 
switching to AHCI without doing some preparation meant that your OS 
would not boot. It's still not an easy switch with Windows 7 either, you 
basically have to install Windows 7 with AHCI already enabled or else 
it'll default to IDE and not include the AHCI drivers in the install. 
Otherwise, switching to AHCI after installing Win 7 is already installed 
is nearly as difficult as XP. Linux could use either type transparently, 
not sure why Microsoft didn't make it as simple with its own drivers.

After doing the switch, I find absolutely no difference in performance. 
However, I do have an external eSATA drive which can be enabled and 
disabled on the fly just like a USB drive. I think if I were still using 
IDE drivers, that wouldn't be nearly as easy though.

	Yousuf Khan

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#2254

On 04/01/2012 06:07, Yousuf Khan wrote:
> On 03/01/2012 1:30 PM, Lynn McGuire wrote:
>> What is the fastest hard drive access method for Windows 7 x64, IDE
>> or AHCI ? I have a WD 1 TB caviar black, a Gigabyte z68xp-ud5
>> motherboard and a Intel I3-2500K with 8 GB of ram.
>>
>> I see these thoughts:
>> http://expertester.wordpress.com/2008/07/24/ahci-vs-ide-%E2%80%93-benchmark-advantage/
>>
>>
>>
>> http://tweaks.com/windows/44119/improve-sata-hard-disk-performance-convert-from-ide-to-ahci/
>>
>>
>
> I did the switch to AHCI back in the Windows XP days. At that time it
>  was a difficult transition as there were no default AHCI drivers,
> and switching to AHCI without doing some preparation meant that your
> OS would not boot. It's still not an easy switch with Windows 7
> either, you basically have to install Windows 7 with AHCI already
> enabled or else it'll default to IDE and not include the AHCI drivers
> in the install. Otherwise, switching to AHCI after installing Win 7
> is already installed is nearly as difficult as XP. Linux could use
> either type transparently, not sure why Microsoft didn't make it as
> simple with its own drivers.
>

It's hard to comprehend MS's difficulty here.  There is little 
measurable difference in performance between IDE mode and AHCI mode, but 
people often /perceive/ "native SATA" mode as newer and faster than "IDE 
emulation" mode.  So even if you can't measure a difference, it still 
seems absurd that you have to jump through hoops to run "native SATA".

> After doing the switch, I find absolutely no difference in
> performance. However, I do have an external eSATA drive which can be
> enabled and disabled on the fly just like a USB drive. I think if I
> were still using IDE drivers, that wouldn't be nearly as easy
> though.
>

There are two main differences in practice between SATA and IDE modes. 
One is hotplug, as you mentioned, and the other is NCQ - native command 
queueing.  (There are also a few other SATA commands, such as SSD trim 
and secure erase.)

NCQ won't make a significant difference in Linux, since it has always 
had good algorithms to order disk accesses to minimise head movement. 
It will sometimes make things worse, such as when the OS wants to 
enforce a particular order (for transactions to filesystem journals, for 
example).  And NCQ doesn't help windows much either - after all, it only 
applies when you do more than one thing at a time.

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#2255

David Brown wrote
> Yousuf Khan wrote
>> Lynn McGuire wrote

>>> What is the fastest hard drive access method for Windows 7 x64, IDE or AHCI ? I have a WD 1 TB caviar black, a 
>>> Gigabyte z68xp-ud5
>>> motherboard and a Intel I3-2500K with 8 GB of ram.

>>> I see these thoughts:
>>> http://expertester.wordpress.com/2008/07/24/ahci-vs-ide-%E2%80%93-benchmark-advantage/
>>> http://tweaks.com/windows/44119/improve-sata-hard-disk-performance-convert-from-ide-to-ahci/

>> I did the switch to AHCI back in the Windows XP days. At that time it  was a difficult transition as there were no 
>> default AHCI drivers,
>> and switching to AHCI without doing some preparation meant that your OS would not boot. It's still not an easy switch 
>> with Windows 7
>> either, you basically have to install Windows 7 with AHCI already
>> enabled or else it'll default to IDE and not include the AHCI drivers
>> in the install. Otherwise, switching to AHCI after installing Win 7
>> is already installed is nearly as difficult as XP. Linux could use
>> either type transparently, not sure why Microsoft didn't make it as
>> simple with its own drivers.

> It's hard to comprehend MS's difficulty here.

For you, sure.

> There is little measurable difference in performance between IDE mode and AHCI mode,

Yes.

> but people often /perceive/ "native SATA" mode as newer and faster than "IDE emulation" mode.

More fool them.

> So even if you can't measure a difference,

Corse you can.

> it still seems absurd that you have to jump through hoops to run "native SATA".

Why when the difference is so trivial ?

>> After doing the switch, I find absolutely no difference in performance. However, I do have an external eSATA drive 
>> which can be enabled and disabled on the fly just like a USB drive. I think if I were still using IDE drivers, that 
>> wouldn't be nearly as easy though.

> There are two main differences in practice between SATA and IDE modes.
> One is hotplug, as you mentioned, and the other is NCQ - native command queueing.  (There are also a few other SATA 
> commands, such as SSD trim and secure erase.)

> NCQ won't make a significant difference in Linux, since it has always
> had good algorithms to order disk accesses to minimise head movement.

And so does Win.

> It will sometimes make things worse, such as when the OS wants to enforce a particular order (for transactions to 
> filesystem journals,
> for example).  And NCQ doesn't help windows much either

Wrong.

> - after all, it only applies when you do more than one thing at a time.

Which Win does all the time. 

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#2256

On 04/01/2012 10:32, Rod Speed wrote:
> David Brown wrote
>> Yousuf Khan wrote
>>> Lynn McGuire wrote
>
>>>> What is the fastest hard drive access method for Windows 7 x64,
>>>> IDE or AHCI ? I have a WD 1 TB caviar black, a Gigabyte
>>>> z68xp-ud5 motherboard and a Intel I3-2500K with 8 GB of ram.
>
>>>> I see these thoughts:
>>>> <http://expertester.wordpress.com/2008/07/24/ahci-vs-ide-%E2%80%93-benchmark-advantage/ >
>>>>
>>>><http://tweaks.com/windows/44119/improve-sata-hard-disk-performance-convert-from-ide-to-ahci/>
>
>>> I did the switch to AHCI back in the Windows XP days. At that
>>> time it  was a difficult transition as there were no default AHCI
>>> drivers, and switching to AHCI without doing some preparation
>>> meant that your OS would not boot. It's still not an easy switch
>>> with Windows 7 either, you basically have to install Windows 7
>>> with AHCI already enabled or else it'll default to IDE and not
>>> include the AHCI drivers in the install. Otherwise, switching to
>>> AHCI after installing Win 7 is already installed is nearly as
>>> difficult as XP. Linux could use either type transparently, not
>>> sure why Microsoft didn't make it as simple with its own
>>> drivers.
>
>> It's hard to comprehend MS's difficulty here.
>
> For you, sure.
>
>> There is little measurable difference in performance between IDE
>> mode and AHCI mode,
>
> Yes.
>
>> but people often /perceive/ "native SATA" mode as newer and faster
>> than "IDE emulation" mode.
>
> More fool them.
>
>> So even if you can't measure a difference,
>
> Corse you can.
>
>> it still seems absurd that you have to jump through hoops to run
>> "native SATA".
>
> Why when the difference is so trivial ?

You do realise you are arguing against yourself here, don't you?  First 
you agree that there is only a trivial difference in performance between 
IDE and AHCI modes, then you argue that "of course" you can measure it, 
then you argue that there is little point in using it (on Windows) since 
the differences are trivial...

Back to reality.  Yes, the performance differences are trivial.  Yes, 
they /can/ be measured - but the differences are below the noise 
threshold for most windows machines.  To measure them, you have to be 
careful about test conditions, background services, repetition of the 
tests, clean installs, etc.  That's fine for a website specialising in 
tests and benchmarks, but of little use to most people.

However, whatever the technical benefits (or lack thereof) of using AHCI 
instead of IDE, user perception and expectation should be important to a 
supplier like MS.  The effort needed to get hard drive drivers in place 
and working in Windows, and the scope for getting it wrong and causing 
problems, is just silly when you look at how simple it is with Linux.

>
>>> After doing the switch, I find absolutely no difference in
>>> performance. However, I do have an external eSATA drive which can
>>> be enabled and disabled on the fly just like a USB drive. I think
>>> if I were still using IDE drivers, that wouldn't be nearly as
>>> easy though.
>
>> There are two main differences in practice between SATA and IDE
>> modes. One is hotplug, as you mentioned, and the other is NCQ -
>> native command queueing.  (There are also a few other SATA
>> commands, such as SSD trim and secure erase.)
>
>> NCQ won't make a significant difference in Linux, since it has
>> always had good algorithms to order disk accesses to minimise head
>> movement.
>
> And so does Win.

I wasn't talking about Windows here.

>
>> It will sometimes make things worse, such as when the OS wants to
>> enforce a particular order (for transactions to filesystem
>> journals, for example).  And NCQ doesn't help windows much either
>
> Wrong.
>

No, it is correct - NCQ doesn't help windows much.  Benchmarks vary, as 
it depends heavily on the usage patterns.  It is a win in some cases, 
and a loss on others - but seldom by particularly large margins.

>> - after all, it only applies when you do more than one thing at a
>> time.
>
> Which Win does all the time.
>
>

I knew that would provoke you :-)

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#2265

David Brown wrote
> Rod Speed wrote
>> David Brown wrote
>>> Yousuf Khan wrote
>>>> Lynn McGuire wrote

>>>>> What is the fastest hard drive access method for Windows 7 x64, IDE or AHCI ? I have a WD 1 TB caviar black, a 
>>>>> Gigabyte
>>>>> z68xp-ud5 motherboard and a Intel I3-2500K with 8 GB of ram.

>>>>> I see these thoughts:
>>>>> <http://expertester.wordpress.com/2008/07/24/ahci-vs-ide-%E2%80%93-benchmark-advantage/

>>>>> <http://tweaks.com/windows/44119/improve-sata-hard-disk-performance-convert-from-ide-to-ahci/>

>>>> I did the switch to AHCI back in the Windows XP days. At that
>>>> time it  was a difficult transition as there were no default AHCI
>>>> drivers, and switching to AHCI without doing some preparation
>>>> meant that your OS would not boot. It's still not an easy switch
>>>> with Windows 7 either, you basically have to install Windows 7
>>>> with AHCI already enabled or else it'll default to IDE and not
>>>> include the AHCI drivers in the install. Otherwise, switching to
>>>> AHCI after installing Win 7 is already installed is nearly as
>>>> difficult as XP. Linux could use either type transparently, not
>>>> sure why Microsoft didn't make it as simple with its own drivers.

>>> It's hard to comprehend MS's difficulty here.

>> For you, sure.

>>> There is little measurable difference in performance between IDE mode and AHCI mode,

>> Yes.

>>> but people often /perceive/ "native SATA" mode as newer and faster than "IDE emulation" mode.

>> More fool them.

>>> So even if you can't measure a difference,

>> Corse you can.

>>> it still seems absurd that you have to jump through hoops to run "native SATA".

>> Why when the difference is so trivial ?

> You do realise you are arguing against yourself here, don't you?

Like hell I am.

> First you agree that there is only a trivial difference in performance between IDE and AHCI modes,

I didnt agree with your TRIVIAL claim, just what you actually said, LITTLE difference.

> then you argue that "of course" you can measure it,

Her first link clearly shows that it can be measured.

> then you argue that there is little point in using it (on Windows) since the differences are trivial...

No I did not. One obvious reason to use it is if you use the hot plugging.

> Back to reality.

You wouldnt know what reality was if bit you on your lard arse.

> Yes, the performance differences are trivial.

Not always.

> Yes, they /can/ be measured - but the differences are below the noise threshold for most windows machines.

That is just plain wrong.

> To measure them, you have to be careful about test conditions, background services, repetition of the tests, clean 
> installs, etc.

Wrong, as always.

> That's fine for a website specialising in tests and benchmarks, but of little use to most people.

Irrelevant to it providing support for hot plugging that IDE does not.

> However, whatever the technical benefits (or lack thereof) of using AHCI instead of IDE, user perception and 
> expectation should be important to a supplier like MS.

Mindlessly silly.

> The effort needed to get hard drive drivers in place and working in Windows,

Is completely trivial with Win7

> and the scope for getting it wrong and causing problems,

Thats a lie with Win7.

> is just silly when you look at how simple it is with Linux.

Its even simpler with Win7.

>>>> After doing the switch, I find absolutely no difference in performance. However, I do have an external eSATA drive 
>>>> which can be enabled and disabled on the fly just like a USB drive. I think if I were still using IDE drivers, that 
>>>> wouldn't be nearly as easy though.

>>> There are two main differences in practice between SATA and IDE
>>> modes. One is hotplug, as you mentioned, and the other is NCQ -
>>> native command queueing.  (There are also a few other SATA
>>> commands, such as SSD trim and secure erase.)

>>> NCQ won't make a significant difference in Linux, since it has always had good algorithms to order disk accesses to 
>>> minimise head movement.

>> And so does Win.

> I wasn't talking about Windows here.

You clearly were.

>>> It will sometimes make things worse, such as when the OS wants to enforce a particular order (for transactions to 
>>> filesystem journals, for example).  And NCQ doesn't help windows much either

>> Wrong.

> No, it is correct - NCQ doesn't help windows much.

Depends on how you define much and which sort of work you are talking about.

> Benchmarks vary, as it depends heavily on the usage patterns.

And it does help some usage patterns significantly.

> It is a win in some cases,

Yes.

> and a loss on others

Hardly ever in many real world situations.

> - but seldom by particularly large margins.

Only because most real work isnt particularly drive IO bound anymore.

>>> - after all, it only applies when you do more than one thing at a time.

>> Which Win does all the time.

> I knew that would provoke you :-)

You spew mindless silly shit, you can be quite confident that I will point that out if I
notice that and can be bothered to expose you stupiditys for the world to laugh at, again. 

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#2268

On 04/01/12 21:37, Rod Speed wrote:
> David Brown wrote

>
>> I knew that would provoke you :-)
>
> You spew mindless silly shit, you can be quite confident that I will point that out if I
> notice that and can be bothered to expose you stupiditys for the world to laugh at, again.
>

It doesn't matter what I write - your Rodbot mode goes on automatic. 
But it is sometimes mildly entertaining to see how easy it is to trigger 
your outbursts of witless knee-jerk childishness.

It's a pity, really.  I know that deep down below the image of a sad, 
angry flamer lies a fair amount of knowledge and experience.  But once 
someone suggests you might be wrong on a point, your Rodbot alter-ego 
takes over, and the sane Rod is lost.

Do you act the same in real life, or is this just your Usenet persona?

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#2270

David Brown wrote
> Rod Speed wrote
>> David Brown wrote

>>> I knew that would provoke you :-)

>> You spew mindless silly shit, you can be quite confident that I will point that out if I notice that and can be 
>> bothered to expose you stupiditys for the world to laugh at, again.

> It doesn't matter what I write - your Rodbot mode goes on automatic.

Everyone can see for themselves that you are lying, just like you
always end up doing when you have got done like a fucking dinner,
just like you always are when you desperately attempt to bullshit
and lie your way out of your predicament when you mindless silly
shit is exposed for the whole world to laugh at, as it always is.

<reams of your puerile attempt at insults any 2 year old could leave for dead flushed where it belongs>

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#2271

On 1/4/2012 1:56 PM, David Brown wrote:
> On 04/01/12 21:37, Rod Speed wrote:
>> David Brown wrote

> It's a pity, really. I know that deep down below the image of a sad,
> angry flamer

Lots of us have Roddy filtered out.

-- 
Ed Light

Better World News TV Channel:
http://realnews.com

Iraq Veterans Against the War and Related:
http://ivaw.org
http://couragetoresist.org
http://antiwar.com

Send spam to the FTC at
spam@uce.gov
Thanks, robots.

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#2272

En el artículo <HY-dnbi5joOPVpnSnZ2dnUVZ8oSdnZ2d@lyse.net>, David Brown
<david.brown@removethis.hesbynett.no> escribió:

>It doesn't matter what I write - your Rodbot mode goes on automatic. 
>But it is sometimes mildly entertaining to see how easy it is to trigger 
>your outbursts of witless knee-jerk childishness.

Funny isn't it, how he feels threatened and lashes out when confronted
by someone who actually knows what they are talking about?

>It's a pity, really.  I know that deep down below the image of a sad, 
>angry flamer lies a fair amount of knowledge and experience.

i.e. he's a dinosaur

>Do you act the same in real life, or is this just your Usenet persona?

I have in my mind's eye a sad, lonely individual who masturbates
obsessively over his collection of ST225's.

-- 
 (\_/)
(='.'=)
(")_(")

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#2273

Mike Tomlinson wrote

> Funny isn't it, how he feels threatened and lashes out when confronted
> by someone who actually knows what they are talking about?

That fool never does with Win.

You never ever do with anything at all, ever.

> I have in my mind's eye a sad, lonely individual who
> masturbates obsessively over his collection of ST225's.

You're projecting now. I dont even have even one, fuckwit. 

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#2257

On 04/01/2012 2:53 AM, David Brown wrote:
> NCQ won't make a significant difference in Linux, since it has always
> had good algorithms to order disk accesses to minimise head movement. It
> will sometimes make things worse, such as when the OS wants to enforce a
> particular order (for transactions to filesystem journals, for example).
> And NCQ doesn't help windows much either - after all, it only applies
> when you do more than one thing at a time.

I find that it doesn't even help even when multitasking. I monitor the 
disk subsection of the Resource Monitor regularly, and very often when 
the disk is busy the Disk Queue Length is over 1.00 (meaning more than 1 
process is actively waiting on the disk) and the Active Time is pegged 
near 100%. Nothing that can be done about it till SSD's are more affordable.

	Yousuf Khan

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#2258

On 04/01/2012 15:29, Yousuf Khan wrote:
> On 04/01/2012 2:53 AM, David Brown wrote:
>> NCQ won't make a significant difference in Linux, since it has always
>> had good algorithms to order disk accesses to minimise head movement. It
>> will sometimes make things worse, such as when the OS wants to enforce a
>> particular order (for transactions to filesystem journals, for example).
>> And NCQ doesn't help windows much either - after all, it only applies
>> when you do more than one thing at a time.
>
> I find that it doesn't even help even when multitasking. I monitor the
> disk subsection of the Resource Monitor regularly, and very often when
> the disk is busy the Disk Queue Length is over 1.00 (meaning more than 1
> process is actively waiting on the disk) and the Active Time is pegged
> near 100%. Nothing that can be done about it till SSD's are more
> affordable.
>
> Yousuf Khan

NCQ can only really help if you have multiple outstanding transactions, 
and the OS itself hasn't ordered them appropriately.  Since the OS 
(Windows or Linux) /does/ order transactions, NCQ will only help if the 
OS is doing a bad job.  The disk knows a bit more than the OS regarding 
disk ordering (since it knows the full 3D geometry, rather than just a 
linear LBA number), but on the other hand it knows nothing about which 
processes are waiting for disk access, or the priorities of said 
accesses, and it knows nothing about barrier writes.  I don't know how 
Windows handles write barriers, but on Linux they are important to 
ensure the integrity of critical disk accesses such as journalling - 
they ensure that everything that was supposed to be written earlier 
/has/ been written.  NCQ totally screws this up, and means that the OS's 
IO subsystem must ensure the disk queue is completely empty before 
sending the barrier write, and wait for it to finish completely before 
sending anything else.  If the disk handles transactions in the order 
they are given, then such writes can be buffered better.

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#2264

David Brown <david@westcontrol.removethisbit.com> wrote:
> On 04/01/2012 15:29, Yousuf Khan wrote:
>> On 04/01/2012 2:53 AM, David Brown wrote:
>>> NCQ won't make a significant difference in Linux, since it has always
>>> had good algorithms to order disk accesses to minimise head movement. It
>>> will sometimes make things worse, such as when the OS wants to enforce a
>>> particular order (for transactions to filesystem journals, for example).
>>> And NCQ doesn't help windows much either - after all, it only applies
>>> when you do more than one thing at a time.
>>
>> I find that it doesn't even help even when multitasking. I monitor the
>> disk subsection of the Resource Monitor regularly, and very often when
>> the disk is busy the Disk Queue Length is over 1.00 (meaning more than 1
>> process is actively waiting on the disk) and the Active Time is pegged
>> near 100%. Nothing that can be done about it till SSD's are more
>> affordable.
>>
>> Yousuf Khan

> NCQ can only really help if you have multiple outstanding transactions, 
> and the OS itself hasn't ordered them appropriately.  Since the OS 
> (Windows or Linux) /does/ order transactions, NCQ will only help if the 
> OS is doing a bad job.  The disk knows a bit more than the OS regarding 
> disk ordering (since it knows the full 3D geometry, rather than just a 
> linear LBA number), but on the other hand it knows nothing about which 
> processes are waiting for disk access, or the priorities of said 
> accesses, and it knows nothing about barrier writes.  I don't know how 
> Windows handles write barriers, but on Linux they are important to 
> ensure the integrity of critical disk accesses such as journalling - 
> they ensure that everything that was supposed to be written earlier 
> /has/ been written.  NCQ totally screws this up, and means that the OS's 
> IO subsystem must ensure the disk queue is completely empty before 
> sending the barrier write, and wait for it to finish completely before 
> sending anything else.  If the disk handles transactions in the order 
> they are given, then such writes can be buffered better.

Well, yes. Write-barriers are getting more and more important
on Linux, with filesystems deferring more and using jourmalling
more agressively. Looks like NCQ is basically obsolete. 

If I remember correctly, it is a thing that was brought on in
SCSI disks a long time ago, when it still had merit. Not so 
anymore, just one more TLA that can be trhown at customers
to make them think they are getting more for their money.

Arno 
-- 
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@wagner.name
GnuPG:  ID: 1E25338F  FP: 0C30 5782 9D93 F785 E79C  0296 797F 6B50 1E25 338F
----
Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans

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#2269

On 04/01/12 20:19, Arno wrote:
> David Brown<david@westcontrol.removethisbit.com>  wrote:
>> On 04/01/2012 15:29, Yousuf Khan wrote:
>>> On 04/01/2012 2:53 AM, David Brown wrote:
>>>> NCQ won't make a significant difference in Linux, since it has always
>>>> had good algorithms to order disk accesses to minimise head movement. It
>>>> will sometimes make things worse, such as when the OS wants to enforce a
>>>> particular order (for transactions to filesystem journals, for example).
>>>> And NCQ doesn't help windows much either - after all, it only applies
>>>> when you do more than one thing at a time.
>>>
>>> I find that it doesn't even help even when multitasking. I monitor the
>>> disk subsection of the Resource Monitor regularly, and very often when
>>> the disk is busy the Disk Queue Length is over 1.00 (meaning more than 1
>>> process is actively waiting on the disk) and the Active Time is pegged
>>> near 100%. Nothing that can be done about it till SSD's are more
>>> affordable.
>>>
>>> Yousuf Khan
>
>> NCQ can only really help if you have multiple outstanding transactions,
>> and the OS itself hasn't ordered them appropriately.  Since the OS
>> (Windows or Linux) /does/ order transactions, NCQ will only help if the
>> OS is doing a bad job.  The disk knows a bit more than the OS regarding
>> disk ordering (since it knows the full 3D geometry, rather than just a
>> linear LBA number), but on the other hand it knows nothing about which
>> processes are waiting for disk access, or the priorities of said
>> accesses, and it knows nothing about barrier writes.  I don't know how
>> Windows handles write barriers, but on Linux they are important to
>> ensure the integrity of critical disk accesses such as journalling -
>> they ensure that everything that was supposed to be written earlier
>> /has/ been written.  NCQ totally screws this up, and means that the OS's
>> IO subsystem must ensure the disk queue is completely empty before
>> sending the barrier write, and wait for it to finish completely before
>> sending anything else.  If the disk handles transactions in the order
>> they are given, then such writes can be buffered better.
>
> Well, yes. Write-barriers are getting more and more important
> on Linux, with filesystems deferring more and using jourmalling
> more agressively. Looks like NCQ is basically obsolete.
>
> If I remember correctly, it is a thing that was brought on in
> SCSI disks a long time ago, when it still had merit. Not so
> anymore, just one more TLA that can be trhown at customers
> to make them think they are getting more for their money.
>
> Arno

The feature introduced on SCSI was TCQ - Tagged Command Queuing.  It was 
more flexible, and more useful - each command sent to the disk could be 
tagged as "head of queue" (do this command with highest priority), 
"ordered" (enforcing the order of the tagged commands) and "simple" (do 
in whatever order the disk wants).  NCQ is pretty much TCQ "simple".  If 
SATA supported the "ordered" mode of TCQ, it would be very useful.  I 
don't know what happens when mixing different tag types in TCQ, but I 
think if "order" had top priority for writes, "head of queue" had top 
priority for reads, and "simple" had lowest priority for both, then 
you'd have a system that would improve speed in almost all cases as well 
as being easy to make write-barrier safe.

I assume that SAS supports TCQ.

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#2275

David Brown <david.brown@removethis.hesbynett.no> wrote:
> On 04/01/12 20:19, Arno wrote:
>> David Brown<david@westcontrol.removethisbit.com>  wrote:
>>> On 04/01/2012 15:29, Yousuf Khan wrote:
>>>> On 04/01/2012 2:53 AM, David Brown wrote:
>>>>> NCQ won't make a significant difference in Linux, since it has always
>>>>> had good algorithms to order disk accesses to minimise head movement. It
>>>>> will sometimes make things worse, such as when the OS wants to enforce a
>>>>> particular order (for transactions to filesystem journals, for example).
>>>>> And NCQ doesn't help windows much either - after all, it only applies
>>>>> when you do more than one thing at a time.
>>>>
>>>> I find that it doesn't even help even when multitasking. I monitor the
>>>> disk subsection of the Resource Monitor regularly, and very often when
>>>> the disk is busy the Disk Queue Length is over 1.00 (meaning more than 1
>>>> process is actively waiting on the disk) and the Active Time is pegged
>>>> near 100%. Nothing that can be done about it till SSD's are more
>>>> affordable.
>>>>
>>>> Yousuf Khan
>>
>>> NCQ can only really help if you have multiple outstanding transactions,
>>> and the OS itself hasn't ordered them appropriately.  Since the OS
>>> (Windows or Linux) /does/ order transactions, NCQ will only help if the
>>> OS is doing a bad job.  The disk knows a bit more than the OS regarding
>>> disk ordering (since it knows the full 3D geometry, rather than just a
>>> linear LBA number), but on the other hand it knows nothing about which
>>> processes are waiting for disk access, or the priorities of said
>>> accesses, and it knows nothing about barrier writes.  I don't know how
>>> Windows handles write barriers, but on Linux they are important to
>>> ensure the integrity of critical disk accesses such as journalling -
>>> they ensure that everything that was supposed to be written earlier
>>> /has/ been written.  NCQ totally screws this up, and means that the OS's
>>> IO subsystem must ensure the disk queue is completely empty before
>>> sending the barrier write, and wait for it to finish completely before
>>> sending anything else.  If the disk handles transactions in the order
>>> they are given, then such writes can be buffered better.
>>
>> Well, yes. Write-barriers are getting more and more important
>> on Linux, with filesystems deferring more and using jourmalling
>> more agressively. Looks like NCQ is basically obsolete.
>>
>> If I remember correctly, it is a thing that was brought on in
>> SCSI disks a long time ago, when it still had merit. Not so
>> anymore, just one more TLA that can be trhown at customers
>> to make them think they are getting more for their money.
>>
>> Arno

> The feature introduced on SCSI was TCQ - Tagged Command Queuing.  It was 
> more flexible, and more useful - each command sent to the disk could be 
> tagged as "head of queue" (do this command with highest priority), 
> "ordered" (enforcing the order of the tagged commands) and "simple" (do 
> in whatever order the disk wants).  NCQ is pretty much TCQ "simple".  If 
> SATA supported the "ordered" mode of TCQ, it would be very useful.  I 
> don't know what happens when mixing different tag types in TCQ, but I 
> think if "order" had top priority for writes, "head of queue" had top 
> priority for reads, and "simple" had lowest priority for both, then 
> you'd have a system that would improve speed in almost all cases as well 
> as being easy to make write-barrier safe.

> I assume that SAS supports TCQ.

Ah, yes. TCQ it was indeed.

Arno

-- 
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@wagner.name
GnuPG:  ID: 1E25338F  FP: 0C30 5782 9D93 F785 E79C  0296 797F 6B50 1E25 338F
----
Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans

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#2267

David Brown wrote
> Yousuf Khan wrote
>> David Brown wrote

>>> NCQ won't make a significant difference in Linux, since it has
>>> always had good algorithms to order disk accesses to minimise head
>>> movement. It will sometimes make things worse, such as when the OS
>>> wants to enforce a particular order (for transactions to filesystem
>>> journals, for example). And NCQ doesn't help windows much either -
>>> after all, it only applies when you do more than one thing at a time.

And any modern OS is doing that all the time.

>> I find that it doesn't even help even when multitasking. I monitor
>> the disk subsection of the Resource Monitor regularly, and very
>> often when the disk is busy the Disk Queue Length is over 1.00
>> (meaning more than 1 process is actively waiting on the disk) and the Active Time is pegged near 100%. Nothing that 
>> can be done about it till SSD's are more affordable.

> NCQ can only really help if you have multiple outstanding transactions,

Yes.

> and the OS itself hasn't ordered them appropriately.

Yes.

> Since the OS (Windows or Linux) /does/ order transactions, NCQ will only help if the OS is doing a bad job.

It will also help when it can do a better job.

> The disk knows a bit more than the OS regarding disk ordering (since it knows the full 3D geometry, rather than just a 
> linear LBA number),

And so it can do a much better job when knowing that allows it to decide what
ordering makes sense, something the OS can never do, most obviously with
what is currently the biggest variable now, when something has just gone past
the heads and you will need to wait an entire revolution before it shows up again.

> but on the other hand it knows nothing about which processes are waiting for disk access, or the priorities of said 
> accesses,

The OS doesnt necessarily know that either except with what it initiates itself.

> and it knows nothing about barrier writes.  I don't know how Windows handles write barriers, but on Linux they are 
> important to ensure the integrity of critical disk accesses such as journalling - they ensure that
> everything that was supposed to be written earlier /has/ been written.  NCQ totally screws this up,

Not if the OS allows for it being there.

> and means that the OS's IO subsystem must ensure the disk queue is completely empty before sending the barrier write,

Wrong.

> and wait for it to finish completely before sending anything else.

Wrong.

> If the disk handles transactions in the order they are given, then such writes can be buffered better.

Wrong. 

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