I hope I am not duplicating something here. . . . I did look - Honest!
I ran into an interesting problem and found an easy fix.
First: I wanted to ENABLE AHCI because (supposedly) it improves HDD performance. (It also enables a host of other interesting features.)
I discovered the trick of setting the START paramater in the registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msahci
from "3" to "0" - and then making the switch in the BIOS.
I tried to switch back, and simply resetting this start value to "3" doesn't work.
The issue here is that there are actually TWO keys that control the IDE/AHCI interface choice:
What works for me is setting both START values to the values that correspond to the interface I wish to use.
It should be trivially easy with a couple of judicious exports to make two registry files, one of which enables AHCI, the other of which enables IDE, by combining the two keys into one file, and setting the START parameters appropriately.
On a slightly different topic, one may ask WHY would someone want to flip back-and-forth between interfaces anyway? Shouldn't the interface selection be a "one-shot-deal"?
In my case I am taking some physical system hard drives and converting them to virtual disks (vhd's) to run them in virtual systems. Unfortunately the 2008-R2 hypervisor only supplies IDE type interfaces for boot devices. So - if I have a system configured for AHCI and want to virtualize it, I have to switch it back to IDE before I make the virtual image of the drive.
In the reverse scenerio, I may want to take a vhd image and write it to physical media - and if I want to ultimately set it to AHCI, I would have to make the corresponding flip in the Registry before swapping interfaces.
What say ye?
Jim
I ran into an interesting problem and found an easy fix.
First: I wanted to ENABLE AHCI because (supposedly) it improves HDD performance. (It also enables a host of other interesting features.)
I discovered the trick of setting the START paramater in the registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msahci
from "3" to "0" - and then making the switch in the BIOS.
I tried to switch back, and simply resetting this start value to "3" doesn't work.
The issue here is that there are actually TWO keys that control the IDE/AHCI interface choice:
- HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msahci
- HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\pciide
- msahci's START value is "3"
- pciide's START value is "0"
- msahci's START value is "0"
- pciide's START value is "3"
What works for me is setting both START values to the values that correspond to the interface I wish to use.
It should be trivially easy with a couple of judicious exports to make two registry files, one of which enables AHCI, the other of which enables IDE, by combining the two keys into one file, and setting the START parameters appropriately.
On a slightly different topic, one may ask WHY would someone want to flip back-and-forth between interfaces anyway? Shouldn't the interface selection be a "one-shot-deal"?
In my case I am taking some physical system hard drives and converting them to virtual disks (vhd's) to run them in virtual systems. Unfortunately the 2008-R2 hypervisor only supplies IDE type interfaces for boot devices. So - if I have a system configured for AHCI and want to virtualize it, I have to switch it back to IDE before I make the virtual image of the drive.
In the reverse scenerio, I may want to take a vhd image and write it to physical media - and if I want to ultimately set it to AHCI, I would have to make the corresponding flip in the Registry before swapping interfaces.
What say ye?
Jim
My Computer
At a glance
Two soup cans and some string.Multi-Processor - TWO large rubber bands!Huh? Wassit?! I don't remember. . .
- Computer type
- PC/Desktop
- OS
- Two soup cans and some string.
- CPU
- Multi-Processor - TWO large rubber bands!
- Memory
- Huh? Wassit?! I don't remember. . .
- Monitor(s) Displays
- Etch-a-Sketch.
- Screen Resolution
- To have less glitches this year.
- Mouse
- Nope. Killed 'em all off last summer.
- Other Info
- I actually have several machines that all frustrate me. That's why I'm here, not to try and impress people with sordid tales of outrageous hardware.
