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Dear Andre,
May I make a suggestion? As in the ATA6 AV Feature Set
proposal a good definition of the command completion time
would be the time from the command register being
written to the last interrupt of the last sector transferred.
This allows true device performance to be measured, but requires
that the IDE driver, and associated structure includes a mechanism
to transfer the times beyond the kernel. This is highly OS specific, I
know, but it is the only true way to HDD performance without dedicated
hardware.
At Philips we have modified the request structure to include a Start
Time and a Finish Time for a request. In such a way very accurate
HDD performance can be measured, such as head & track skews,
for example.
Would it be possible to include such time fields in the standard IDE driver?
For the AV Feature Set the IDE driver it would be useful if the IDE driver would
return a measured command time.
Provisionally, even in the Taskfile Interface this would be welcomed. I assume
that you are currently defining what should come into the IDE driver for ATA6,
so this may be an option. Would you be prepared to discuss this further?
Kind regards,
Stephen.
--
Dr. Stephen Cumpson, Senior Scientist,
Group Storage Technologies, Building WY 1 45, (WY12),
Philips Research Labs., Prof. Holstlaan 4, 5656 AA Eindhoven, The Netherlands
Tel.: +31 40 274 2762 Fax: +31 40 274 4927
Email: mailto:[EMAIL PROTECTED]
Web: http://www.research.philips.com/
[EMAIL PROTECTED]@[EMAIL PROTECTED] on 17/05/2001 10:19:30
Please respond to [EMAIL PROTECTED]@SMTP
Sent by: [EMAIL PROTECTED]
To: [EMAIL PROTECTED]@SMTP
cc:
Subject: [temp t13] Re: ATA speed test
Classification:
** This is the quasi-official and semi-temporary T13 email list server. **
Oh be a little more generious Hale...
I will be happy to give people performance code, but you can not use it on
any other OS so I get more people to my OS. Of course everyone knows the
overhead in the CR3's and/or context switching on memcpy issues. OOPS,
that is a compiler variation....
Yeah, you are right Hale....
No need to add to the ATA<->SCSI CAM layer required by others.
Cheers,
Andre Hedrick
Linux ATA Development
On Wed, 16 May 2001, Hale Landis wrote:
> Date: Wed, 16 May 2001 22:34:26 -0600
> From: Hale Landis <[EMAIL PROTECTED]>
> Reply-To: [EMAIL PROTECTED]
> To: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
> Subject: [temp t13] Re: ATA speed test
>
> ** This is the quasi-official and semi-temporary T13 email list server. **
>
> On Thu, 17 May 2001 09:37:51 +0530, SHIBU BABY wrote:
> >I had done a search on www.ata-atapi.com and I can't find anything related
> >to speed test there. I think Hale can give the exact URL
>
> I think the reference to my web site was for the purpose of getting
> my ATADRVR source code.
>
> HOWEVER...
>
> I generally do not get involved in discussions of disk drive
> performance and I do not develop or distribute disk drive performance
> testing software. There are reasons for this: The vast majority of
> people trying to test disk drive performance: 1) do not have the
> slightest clue as to how a disk drive works these days, 2) do not
> understand the difference between using the various ATA data transfer
> modes, 3) do not understand how the average OS uses a disk drive, 4)
> always seem to want to test some strange sequence of read/write
> commands or strange transfer sizes. I could go on but I will stop
> there.
>
>
> *** Hale Landis *** [EMAIL PROTECTED] ***
> *** Niwot, CO USA *** www.ata-atapi.com ***
>
>
> --
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>
>
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