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Windows 7: C drive 1st drive?

06 Oct 2014   #1

Windows 7 Pro 64 bitv & Windows 10 Home
C drive 1st drive?

Got an issue that I do not understand. My H67a-UD3H-B3 has five sata slots (0,1,2,3,4). 0 &1 are sata 3 while 2,3 & 4 are sata 2. I have 4 ssd's and 1 dvd. Primary C is plugged to slot 0. Data drive D is plugged to slot 1. Backup C is plugged to slot 2. Backup D is plugged to slot 3. Dvd is plugged to slot 4.

Disk management and Casper backup shows that the first drive is data drive D and the second drive is primary drive C. Why are they reversed? I thought slot 0 was for the OS drive. Can this cause problems?


My System SpecsSystem Spec
06 Oct 2014   #2

Windows 7 Ultimate 64-bit, Windows 8.1 64-bit, Mac OS X 10.10, Linux Mint 17, Windows 10 Pro TP

How are they showing in the BIOS? Windows, and other Operating Systems, read the BIOS [Basic Input Output System] before they start to determine how to run the motherboard resources available.
My System SpecsSystem Spec
06 Oct 2014   #3
Microsoft MVP

Vista, Windows7, Mint Mate, Zorin, Windows 8

The OS drive can be on any port. And windows does not not map them the same way as they are assigned on the board. I agree that this is a bit confusing, but that's the way it is.
My System SpecsSystem Spec

06 Oct 2014   #4


In spite of the fact that OS disk not disk 0 I would still attempt to have the OS in Disk0 slot if it can be done. This is because we regularly see the boot files have been derailed to a preceding Primary partition during repairs or reinstall.

The only ways to avoid this is to have WIn7 as the first hard drive, disconnect all other drives during reinstall or repairs, or have all preceding partitions be Logical which cannot accept boot files.
My System SpecsSystem Spec
06 Oct 2014   #5

Windows 7 Pro 64 bitv & Windows 10 Home

How are they showing in the BIOS?
Not sure as they are listed as p0 Samsung 840 pro, p1 Samsung 840 pro, p2 Mushkin 120dx & p3 mushkin 120dx.

I agree that this is a bit confusing
Absolutely! Unfortunately, things should make sense to me but sometimes they don't.

Gregrocker, that is some interesting reading!
"I would still attempt to have the OS in Disk0 slot if it can be done"
Exactly what my ocd brain keeps telling me but in reality, I cannot (so far) make it happen. I can disconnect the d drive and reboot which will put the os c drive in slot 0 only until I reconnect the d drive.
Oh well, looks like more experimentation needed!
My System SpecsSystem Spec
06 Oct 2014   #6

Windows 7 Home Premium 64 bit sp1

Perhaps you could post a screen shot of your Disc Management. Make sure it includes all your drives & all the details as well.
My System SpecsSystem Spec
07 Oct 2014   #8

Windows 7 Pro 64 bitv & Windows 10 Home

Sorry guys, had an out of town emergency. Here's the disk management.

Attached Thumbnails
C drive 1st drive?-capture.png  
My System SpecsSystem Spec
07 Oct 2014   #9

Windows 10 Pro (x64)

As long as the physical connect to the HDD/SSD is attached to port 1 for your primary drive then all is well. The logical layout shown in Disk Manager is based on who ever replies first. Disk 0 is just the first drive to reply when the system booted.

Do not concern yourself over this. (The labels in Disk Manager do not correspond to the physical connections.)
My System SpecsSystem Spec
07 Oct 2014   #10

Windows 7x64 Home Premium SP1

Connecting SSDs to sata 3 ports and your primary boot drive to sata port 0 is a good idea. The drive letter allocation is not really important and there not a guaranteed one to one relationship between sata port number and the OS drive number. It has been discussed a number of times before. See here
Diskpart / Disk Management vs the BIOS
My System SpecsSystem Spec

 C drive 1st drive?

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