ACHI versus IDE question

[pjp]

I have a Dell running a 2.8Gz Dual-core Pentium with 4 gigs ram running
Windows 7. I have two hard disks in it and two DVD burners. All SATA.

The system has RAID built-in to BIOS and is set to "Enabled" (I'll get
back to this) in BIOS. The disks themselves are not setup as RAID and if
one enters the BIOS RAID dialog it displays the disks as "non raid".

I'm experiencing some odd disk behavior. Mainly in the form of
noticeable "stalls" for a brief period of time. Also disk transfers both
to same hard disk and/or second hard disk can vary considerably in
speed, even during single transfer.

I've checked background processes etc. enough and been at this long
enough to feel it's more than that but a SATA only system is relatively
new to me.

I'm also unsure if DMA is turned On for all the various drives but
Device manger has no branch for IDE Controllers but instead just the
Storage Controllers branch for the RAID controller and it has no mention
of DMA in it anywhere (or in BIOS setup either)

I know that I can "revert" back to some type of IDE emulation for the
disk drives. I believe one does that with a setting in the BIOS. I also
am led to believe one must first make some registry changes before doing
this change or else Windows 7 will bluescreen upon boot.

I believe I have the required info to make the registry changes (and to
revert back if necessary) so I'm making this query about what will
happen when I reboot after making the BIOS change.

The BIOS change itself seems to be controlled by one setting with
choices 1 ) RAID AUTODETECT/ATA and 2 ) RAID ON.

What I'm assuming is that if I change the setting to ".../ATA" I'm going
to get a system that "mimics" the old IDE type. So info on how the
drives are "assigned" seems pertinent, e.g. does the boot drive have to
be on first/lowest Sata port etc. etc.

Thanks in advance

 

[Paul]

I have a Dell running a 2.8Gz Dual-core Pentium with 4 gigs ram running
Windows 7. I have two hard disks in it and two DVD burners. All SATA.

The system has RAID built-in to BIOS and is set to "Enabled" (I'll get
back to this) in BIOS. The disks themselves are not setup as RAID and if
one enters the BIOS RAID dialog it displays the disks as "non raid".

I'm experiencing some odd disk behavior. Mainly in the form of
noticeable "stalls" for a brief period of time. Also disk transfers both
to same hard disk and/or second hard disk can vary considerably in
speed, even during single transfer.

I've checked background processes etc. enough and been at this long
enough to feel it's more than that but a SATA only system is relatively
new to me.

I'm also unsure if DMA is turned On for all the various drives but
Device manger has no branch for IDE Controllers but instead just the
Storage Controllers branch for the RAID controller and it has no mention
of DMA in it anywhere (or in BIOS setup either)

I know that I can "revert" back to some type of IDE emulation for the
disk drives. I believe one does that with a setting in the BIOS. I also
am led to believe one must first make some registry changes before doing
this change or else Windows 7 will bluescreen upon boot.

I believe I have the required info to make the registry changes (and to
revert back if necessary) so I'm making this query about what will
happen when I reboot after making the BIOS change.

The BIOS change itself seems to be controlled by one setting with
choices 1 ) RAID AUTODETECT/ATA and 2 ) RAID ON.

What I'm assuming is that if I change the setting to ".../ATA" I'm going
to get a system that "mimics" the old IDE type. So info on how the
drives are "assigned" seems pertinent, e.g. does the boot drive have to
be on first/lowest Sata port etc. etc.

Thanks in advance

To prepare Windows 7 for a BIOS storage configuration change (RAID <--> AHCI <--> IDE),
there are some registry entries you change.

http://support.microsoft.com/kb/922976

Windows 7 initially starts, with all the drivers armed and ready to go. On the
first boot, Windows 7 figures out the driver which is the best fit (the
one that "takes"), and the other drivers are disabled. The purpose of
disabling the drivers, is to "save time" on the next boot.

And that means, if you change BIOS settings now, you'll be greeted by an
"inaccessible boot volume" error.

The user can change the registry setting back, to make Windows 7 "more adventurous"
again, and try all the drivers. You do this *before* changing the BIOS setting.
There is one registry setting, per built-in driver type. It can be a problem,
finding an article, with all potential registry settings (perhaps four of them)
mentioned.

So that's how you'd "change modes", if you wanted to.

*******

Note that, some SATA misbehavior is related to "Link Power State". This crap
has been kicking around for a while, and recently Yousuf ran into it again
while installing a new SSD. I can't believe patches haven't been pushed out
to fix this properly.

http://groups.google.com/group/alt....a7261932/ccffdbe46facee24?q=#ccffdbe46facee24

( http://www.sevenforums.com/tutorials/177819-ahci-link-power-management-enable-hipm-dipm.html )

You can find mention of HIPM/DIPM on the Microsoft site.

http://support.microsoft.com/kb/932079

For the last couple of years, you can also find mention of "LPMDSTATE"
on Intel drivers. Which is probably related to the same kind of thing,
a power state issue.

(See the code window in "5a" here, for an example of registry twiddling.)
http://www.ocztechnologyforum.com/f...AHCI-mode-on-Intel-6-series-Chipset-platforms

So you can spend many happy hours researching that and fixing your RAID
situation, and avoiding the switch to IDE, if you want. That's a potential
alternative.

Paul

 

[Yousuf Khan]

I have a Dell running a 2.8Gz Dual-core Pentium with 4 gigs ram running
Windows 7. I have two hard disks in it and two DVD burners. All SATA.

The system has RAID built-in to BIOS and is set to "Enabled" (I'll get
back to this) in BIOS. The disks themselves are not setup as RAID and if
one enters the BIOS RAID dialog it displays the disks as "non raid".

I'm experiencing some odd disk behavior. Mainly in the form of
noticeable "stalls" for a brief period of time. Also disk transfers both
to same hard disk and/or second hard disk can vary considerably in
speed, even during single transfer.

I've checked background processes etc. enough and been at this long
enough to feel it's more than that but a SATA only system is relatively
new to me.

As Paul mentioned, I just finished an idyllic few weeks debugging
similar freezing issue on a new SSD that I recently got. Your behaviour
sounds similar, however, I gather you got HDD's here instead of SSD's. I
have never seen this issue crop up on any of my HDD's in SATA mode, but
I guess if it's possible on an SSD, why shouldn't it be possible on an
HDD? As Paul mentioned, I eventually discovered some obscure settings in
the AHCI drivers that dealt with power management, and once they were
turned off, the freezes went away completely.

However, prior to discovering these obscure power management switches, I
found a coarser solution, which was to revert back to the IDE drivers.
In a sense, the IDE drivers were more reliable because they were more
primitive than the AHCI or RAID drivers. The IDE drivers conform to the
ATA/ATAPI-7 standards, and therefore don't have support for such
features as NCQ, power management, etc., that came afterwards with the
newer ATA=8 standards (which the AHCI drivers conform to). The IDE
driver doesn't know about any of these things, so it doesn't bother with
anything but default settings for most of those new things. So going
back to the IDE drivers is a very valid approach to fixing these issues.
For the most part, the performance differential between IDE and
AHCI/RAID is minuscule.

Now on my system, I started out with SATA ports operating in IDE mode,
and so I had to run the procedure to enable AHCI drivers to be installed
on Windows 7. Once I converted the ports over to the AHCI drivers, I
could then at will go back and forth between AHCI and IDE and
vice-versa, just be resetting them in the BIOS. But you'll have to set
the registry to accept the first conversion, which I gather you have
already figured out.

I'm also unsure if DMA is turned On for all the various drives but
Device manger has no branch for IDE Controllers but instead just the
Storage Controllers branch for the RAID controller and it has no mention
of DMA in it anywhere (or in BIOS setup either)

I know that I can "revert" back to some type of IDE emulation for the
disk drives. I believe one does that with a setting in the BIOS. I also
am led to believe one must first make some registry changes before doing
this change or else Windows 7 will bluescreen upon boot.

I believe I have the required info to make the registry changes (and to
revert back if necessary) so I'm making this query about what will
happen when I reboot after making the BIOS change.

I suppose each driver is different, but when you go back to the
Microsoft IDE drivers, they will definitely tell you whether they are
using DMA, and which mode of DMA is being used (eg. UDMA/33 vs. UDMA/66
vs. UDMA/133, etc.).

I would also suggest if you decide to go back to more advanced drivers,
then don't go back to the proprietary RAID drivers, but go instead to
the Microsoft AHCI drivers, if you have the choice. The hardware may not
give you the choice though.

Also before you change anything, have you checked to see if you have
more advanced RAID drivers for the existing system?

The BIOS change itself seems to be controlled by one setting with
choices 1 ) RAID AUTODETECT/ATA and 2 ) RAID ON.

What I'm assuming is that if I change the setting to ".../ATA" I'm going
to get a system that "mimics" the old IDE type. So info on how the
drives are "assigned" seems pertinent, e.g. does the boot drive have to
be on first/lowest Sata port etc. etc.

No, there is a boot drive order setting in most BIOSes. This lets you
choose which drive is your primary boot drive. You don't have to fiddle
around with cable positions anymore.

Yousuf Khan