Sata Disk 0 and Disk 1

[jsquareg]

For a long while I ran just one HD (Sata) on my machine. It was connected to Sata 1 on the MB and appeared as Disk 0 in Disk Managment. I just connected another Sata drive to Sata 2 on the MB. It shows up as Disk 0 and the original as Disk 1. I had thought the reverse should be true -- Original still as Disk 0 and the new as Disk 1.

BIOS shows the original connected to IDE 3 Master and the added one connected to IDE 3 Slave.

The system works fine with all the partitions and their drive letters I had assigned to them correct.

No big deal. I just wonder why the Disk Management disk numbers appear as they do.

Would someone please help me understand?

Thank you.

 

[stormy13]

This is one of those things that I don't think anyone has really figured out. You're not the first to ask about it, and from the last thread I saw about it pretty sure there was no definitive answer as to why. At the end of the day it will make you wonder why, but it also has no affect on how anything runs. You can sit and rearrange the cables to the motherboard all day long and you might hit the combination that will change them around, but not worth the aggravation.

 

[jsquareg]

Thank you.

So I guess I will right it off as one of those "Life's Imponderables."

 

[DeaconFrost]

There's no mystery about it, if I am understanding your question. The numbers in Disk Management have no relation to the physical ports. If a motherboard has six SATA ports, and the primary hard drive is plugged into the sixth port (SATA5), it will still show as Disk 0 in Disk Management.

 

[jsquareg]

And that is pretty much what happened. The original disk is in Sata 1 it appeared as Disk 0. When I put the second disk on Sata 2 it showed as Disk 0 and the original disk in Sata 1(the one that showed as Disk 0) showed as Disk 1.

There's no mystery about it, if I am understanding your question. The numbers in Disk Management have no relation to the physical ports. If a motherboard has six SATA ports, and the primary hard drive is plugged into the sixth port (SATA5), it will still show as Disk 0 in Disk Management.

 

[DeaconFrost]

I have had times on the same system where a clean install will show the drives in a different order (within Windows). As long as the drive letters are assigned properly, it won't cause any issues.

 

[dustywoodworker]

This is one of those things that I don't think anyone has really figured out. You're not the first to ask about it, and from the last thread I saw about it pretty sure there was no definitive answer as to why. At the end of the day it will make you wonder why, but it also has no affect on how anything runs. You can sit and rearrange the cables to the motherboard all day long and you might hit the combination that will change them around, but not worth the aggravation.

What then makes the primary disk primary? Is it the simple fact that that disk has an operating system thus it is the primary? What if I install a second HD that also has an operating system installed?

 

[OldMX]

I had the same issue, installing the ahci drivers for the sata controller sorted them correctly.

 

[seavixen32]

For a long while I ran just one HD (Sata) on my machine. It was connected to Sata 1 on the MB and appeared as Disk 0 in Disk Managment. I just connected another Sata drive to Sata 2 on the MB. It shows up as Disk 0 and the original as Disk 1. I had thought the reverse should be true -- Original still as Disk 0 and the new as Disk 1.

BIOS shows the original connected to IDE 3 Master and the added one connected to IDE 3 Slave.

The system works fine with all the partitions and their drive letters I had assigned to them correct.

No big deal. I just wonder why the Disk Management disk numbers appear as they do.

Would someone please help me understand?

Thank you.

I'm not quite sure whether I'm absolutely correct, but as far as I'm aware the BIOS recognises the drive that Windows is on as Drive 0.

So even if you connect the Windows drive to SATA 1 it will still show as Drive 0 in disk management.

 

[theog]

Windows will see the HD Drive Disk0 when corrected to the first Sata port with a HD Drive. On Some MOBO the first Sata port is marked Sata 0 or Sata 1.
But if you have a IDE HD Drive also corrected, Windows will see the IDE as Disk0.

 

[dustywoodworker]

Windows will see the HD Drive Disk0 when corrected to the first Sata port with a HD Drive. On Some MOBO the first Sata port is marked Sata 0 or Sata 1.
But if you have a IDE HD Drive also corrected, Windows will see the IDE as Disk0.

If two HDs are connected to the SATA ports, must the intended OS be onboard the lowest numbered SATA port occupied?

What I am really asking, I think, is will the other OS simply be ignored because it is not on the lowest numbered SATA port?

 

[theog]

What I am really asking, I think, is will the other OS simply be ignored because it is not on the lowest numbered SATA port?

Only when the other HD Drive is not connected.

If two HDs are connected to the SATA ports, must the intended OS be onboard the lowest numbered SATA port occupied?

Best installed to lowest numbered SATA port

 

[Sardonicus]

This explains it.....
The disk drive numbers may not correspond as expected to the SATA channel numbers when you set up Windows Vista, Windows Server 2008, Windows Server 2008 R2, or Windows 7 on a computer that has multiple SATA or RAID disks

 

[I18NMaster]

Workaround

I manage labs of test machines that always run multiple sata drives having multiple partitions each. In order for our automated tools to run correctly, drive letters must always be assigned to the correct partitions on each drive. When Vista & Windows 7 started arbitrarily enumerating the first sata drive as disk1 and second one as disk0 during installation, it screwed up all our drive lettering, and hence our automated scripts stopped working.

I searched online for how to correct this but found no easy way. I finally came up with a solution that's a little cumbersome but works every time.

When you start to install Vista / Win7, check which drive it's enumerating as disk0. If it's the one you expect then great - just continue the installation. If NOT, however, follow these steps:
1. Abort the installation, reboot and launch BIOS setup
2. Turn off (disable in BIOS) all drives except the one you want as disk0
3. Save, reboot and restart the installation; it should properly enumerate your desired drive as disk0 (since there are no other drives)
4. After finishing your installation, reboot, launch BIOS setup, and re-enable your other drive(s), then save and reboot again
5. Use the Disk Management tool in Windows to re-assign drive letters (since your CD/DVD-ROM drive(s), etc. will have been assigned lower letters than your hard drives/partitions - easy to fix in Disk Management but it's recommended that you do this before installing any programs on the newly installed OS.

If you don't have the ability to disable a particular sata drive in your BIOS, you'll have to shut down the computer and physically unplug the sata cable from the drive(s) that you don't want showing up during OS installation, then plug them back in after the OS is installed.

 

[mjf]

This has been discussed on a number of occasions. Here is one thread that discusses it and still gets my vote for the best answer (Dwarf's post).
http://www.sevenforums.com/installa...rt-disk-management-vs-bios-2.html#post1519407