This tool did -NOT- find any intel Disk driver listed in the
pc
is this looking like the install process was botched and I am
running some kind
of miss match ??
Think about it this way. If the driver was the least bit suspect, the
computer wouldn't even manage to boot.
The driver works at a low level, like "seek to 124785" or "write 256KB
to 324839". It's a mechanical thing, with the file system abstraction
running on top of it.
One of the things AHCI would be doing, is issuing commands and keeping
track of the commands that get done. AHCI allows commands to be completed
out of sequence, at the discretion of the controller on the disk drive.
If the controller sees a more efficient sequence to improve head movement,
then that is the order the commands get completed. AHCI only really begins
to work, when the "queue" starts to build. Such a situation would be
common on a server, but not so common on a desktop. On a desktop, there
would be a relatively light load.
http://en.wikipedia.org/wiki/Ahci
AHCI = hot-plugging and native command queuing
http://en.wikipedia.org/wiki/Native_Command_Queuing
Most people are installing AHCI on their desktops, so that they get the
"Hot Plug" support that is bundled with the feature. If they knew what
the impact was on performance, they might not be selecting AHCI at all
on the desktop. It's the "Hot Plug" of SATA devices that people are looking
for. Or in the case of some SATA controllers, using AHCI from the day of
installation, means an easy transition to RAID later if needed. Intel
allows migration from single disk AHCI, to multi-disk RAID, without
reformatting, and it may even be done while the OS is running (run time
migration or morphing, depending on which term you like).
*******
On WinXP, there is no support for AHCI built in. On later OSes, the
OS has a file like msahci.sys for that purpose.
If I grab one of the driver files I have on disk here, at random,
this is what I see. This is enough of a driver, to install WinXP
on an AHCI or a RAID disk controller port on an Intel Southbridge.
Which INF file is selected, is determined by the VEN and DEV
(the BIOS puts the chip in a mode, and the VEN and DEV codes help
communicate that mode to the OS and hardware wizard).
Directory of C:\Downloads\RAIDAHCI\Driver\32Bit
08/05/2009 04:52 PM <DIR> .
08/05/2009 04:52 PM <DIR> ..
04/18/2008 10:44 AM 11,509 iaAHCI.cat
04/16/2008 12:53 AM 8,794 iaAHCI.inf
04/18/2008 10:23 AM 11,215 iaStor.cat
04/16/2008 12:53 AM 8,114 iaStor.inf
04/16/2008 01:53 AM 312,344 IaStor.sys
07/26/2006 07:09 PM 11,321 license.txt
04/16/2008 12:53 AM 4,573 TXTSETUP.OEM
If I look in iaAHCI.inf , I see this:
[CopyFullPort]
iaStor.sys
The driver really has only one file in it. The OS will contribute
other files as well (things like atapi.sys). If you look in Device Manager,
and list the drivers for that controller, I'd expect to see iaStor.sys plus
a couple other files in the list.
(If I could have found a picture of the appropriate Device Manager
entry, I would have done that by now. This is the best I can do
here, without attempting to do an actual install.)
*******
One thing to keep in mind, is it is one thing to have the driver
installed, but quite another to have the disk connected to the appropriate
connector on the motherboard. Some motherboards have as many as three
SATA chips on them, and if a user is not careful, they've been running
the whole time, using an entirely different disk controller and driver.
In other words, *check your cabling* , and make sure you're actually
on an Intel port and not some other one.
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