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Windows 7: Q: Drive letters - where stored and how assigned?

05 May 2010   #1

Windows Home Premium (64)
 
 
Q: Drive letters - where stored and how assigned?

Where does Windows 7 store the assigned drive letters for external disks / USB sticks? And how are they assigned if the letters are already is use?

Let's say that the partitions on my internal disks are lettered C, D, E, K, L and M and my DVD drive is lettered Z.

If I plug in a FireWire drive which has 3 partitions lettered G, H and L (lettered using Disk Management on another PC)
-- how will those disk partitions be lettered?
-- will the drive always have the same letters each time it is plugged in?
-- what happens if I then plug the drive back into the other PC (will the partitions still be G,H and L there)?

Similarly how about a USB stick with two partitions, M and N?

And finally, does Windows XP store the drive letters in the same way?


My System SpecsSystem Spec
.

05 May 2010   #2

Windows 7 Profesional x86, Mac OS X 10.6 Snow Leopard
 
 

Hi DarkStar GT.

In answer to your question drives are usually given the first available drive letter available on the system when they are plugged in for the first time; which in most cases amounts to E:/ and then the next disk would be F:/ etc.

You can change which letter is assigned to a specific drive by following this tutorial (Drive Letter - Add, Change, or Remove - Vista Forums) which also will answer at least a few of your questions.

If you explicitly tell Windows to remember a drive letter for a certain drive it will try and give it that drive letter (if available) the next time it is plugged in.

If you were to plug a hard drive that you had told on PC A to be assigned to Z:/ into PC B, PC B would not try and assign the drive to Z:/ unless it was the only available letter.
I believe the only exception to this rule is usb floppy drives which somehow always manage to mount at their traditional drive letter A:/ no matter what PC you're on.

Yes Windows XP does it in exactly the same way.

Oli
My System SpecsSystem Spec
05 May 2010   #3

Windows Home Premium (64)
 
 

Thank you for your reply. So now, this is my understanding:

a) the first time an external device is plugged into a PC, the earliest free drive letters (excluding A:\ and B:\) are assigned. From then on, the device is mounted with the same letters; unless there is a conflict, in which case, the earliest drive letter is assigned.

b) I can also assign drive letters in Disk Management. They will "stick" to the device whenever it is plugged into the PC, any conflicts are handled as above.

c) Plugging the device into another PC may assign different letters.

d) That all suggests that the drive letters and some sort of device identifier are stored in the Registry so that Windows can remember which letters to use for each device that has ever been plugged in.

Does that make sense?
My System SpecsSystem Spec
.


05 May 2010   #4

Windows 7 Profesional x86, Mac OS X 10.6 Snow Leopard
 
 

Quote   Quote: Originally Posted by DarkStar GT View Post
Thank you for your reply. So now, this is my understanding:

a) the first time an external device is plugged into a PC, the earliest free drive letters (excluding A:\ and B:\) are assigned. From then on, the device is mounted with the same letters; unless there is a conflict, in which case, the earliest drive letter is assigned.

b) I can also assign drive letters in Disk Management. They will "stick" to the device whenever it is plugged into the PC, any conflicts are handled as above.

c) Plugging the device into another PC may assign different letters.

d) That all suggests that the drive letters and some sort of device identifier are stored in the Registry so that Windows can remember which letters to use for each device that has ever been plugged in.

Does that make sense?
Bang on! Don't ask me where or how that information is stored, I simply don't know. I would imagine it's stored in a registry key but I'm not sure. Whatever the case may be even if you do find it DON'T GO FIDDLING WITH IT you never know what horrible consequences it may have, this goes for the rest of the registry as well.

I think this article might solve your question Change or Delete System Drive Letter via Registry to Remove Conflict USB or FireWire Drive Letter My Digital Life.

As you are new to the forum I thought you might like to know how to mark threads as solved as well as the uses of some of the other buttons.

To the top right of this post you will see 3 icons. An orange (+), a set of scales and a red and white warning triangle.

The orange (+) or blue (-) denotes whether a user is on or offline (orange = on, blue = off).

The scales are used to give rep points; click this button if someone has helped you significantly or solved your queries (only give this to posts that you think really deserve it).

The red and white warning triangle is used to denote either an abusive post OR to mark a thread as solved (just put solved in the box that comes up and the admins or moderators will mark it solved).

Be sure when the thread is solved that you mark it as solved.

Oli
My System SpecsSystem Spec
06 May 2010   #5

Windows Home Premium (64)
 
 

Handy links; I may well have a read-only look around the Registry.

Thank you for the info about marking a thread solved. I've wondered a few time about that and concluded that the Mods must do it somehow. I did not think to use the "Report this post" link. (I wonder, could its pop-up be changed to read "Report post / Mark as Solved"?
My System SpecsSystem Spec
06 May 2010   #6

Windows 7 Profesional x86, Mac OS X 10.6 Snow Leopard
 
 

Quote   Quote: Originally Posted by DarkStar GT View Post
Handy links; I may well have a read-only look around the Registry.

Thank you for the info about marking a thread solved. I've wondered a few time about that and concluded that the Mods must do it somehow. I did not think to use the "Report this post" link. (I wonder, could its pop-up be changed to read "Report post / Mark as Solved"?
You're most welcome.

I highly doubt they'll change it now because it's just one of those little things you have to learn to do on this forum it's been like that since Vista forums first started (plus it would make my nice little tutorial redundant ).

Oli
My System SpecsSystem Spec
06 May 2010   #7

Windows 7 home premium with 64 bit
 
 

Why don't you just let it assign the next letter in the alphabet or you assign the next letter? You might be partial to favorite letters but it is not worth messing up your computer.
My System SpecsSystem Spec
07 May 2010   #8

Windows Home Premium (64)
 
 

... Because some of my applications rely on fixed letters to locate their data libraries. The apps store the locations in the Registry.
My System SpecsSystem Spec
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 Q: Drive letters - where stored and how assigned?




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