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simple changes to the diskperf filter example

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Dave August

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Dec 3, 2003, 12:03:16 PM12/3/03
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I'd like to make a few simple changes to the diskperf filter example to
gather some information on the Logical Blocks / Sectors that are being
accessed. I can't figure out where the LBA or CHS is being referenced in
the IRP_MJ_READ or IRP_MJ_WRITE calls. I naively thought it would be some
where in currentIrpStack->Parameters, but I guess it's not. Any hint's on
where to look for it.

Dave


David J. Craig

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Dec 3, 2003, 12:43:30 PM12/3/03
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Parameters.Read.ByteOffset.QuadPart

"Dave August" <aug...@NOSPAMacmesi.com> wrote in message
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Dave August

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Dec 3, 2003, 1:03:30 PM12/3/03
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Really David, thanks for the enlightenment.
I (again naively) assumed this was the offset into buffer but hey what do I
know.

Dave

> Parameters.Read.ByteOffset.QuadPart
>


Maxim S. Shatskih

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Dec 3, 2003, 3:01:36 PM12/3/03
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CHS are not referenced at all (they are internal peculiarity of the ATAPI
driver), and LBA can be got as Parameters.Read.ByteOffset.QuadPart /
SectorSize.

--
Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
ma...@storagecraft.com
http://www.storagecraft.com


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David J. Craig

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Dec 3, 2003, 4:43:55 PM12/3/03
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Not anymore. CHS is really a characteristic of the old MFM drives where
each track had a fixed number of sectors, but ZBR, zone bit recording,
changed most of that and any sector may be located anywhere on the media
depending upon the maker of the drive, spare allocation algorithms, etc.
Some drives have/had spare sectors on each track while others have them
beyond the end of the drive. Since I don't work for a drive maker, I don't
know what the current algorithms are for each maker - Hitachi, Seagate,
Maxtor, Western Digital, etc.

"Maxim S. Shatskih" <ma...@storagecraft.com> wrote in message
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Maxim S. Shatskih

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Dec 4, 2003, 5:37:51 AM12/4/03
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Yes, CHS no more reflect the real physical geometry, and it was so IIRC
even with the oldest IDE drives of 80MB or such.
A hint for real physical geometry can be - divide the stream IO transfer
rate to the rotational speed of the drive.

Like - my old IBM UltraStar gives 35MB/s on 10k rpm. So, the estimated
physical track size is 0.21MB - 210KB - 420 sectors. Since the drive is 18GB,
it must have about 85K tracks - on dunno how many surfaces, 4 possibly.

--
Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
ma...@storagecraft.com
http://www.storagecraft.com


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