Another useful Windows tool: USBDLM
What is USBDLM?
USBDLM, or USB Drive Letter Manager, is a free application that will enable you to assign the same windows drive letter to any number of removable storage devices.
Why would I want the same drive letter assigning to multiple removable storage devices?
Usually, in the business environment, more than one USB hard disk drive will be used with a backup solution such as Acronis Backup and Recovery 11 or Symantec Backup Exec 2012. Some companies will have 5 disks, one for every day of the week, whereas some companies may choose to just have 2 disks and alternate them. You can imagine now, how important it is for the backup application to have the correct drive letter when backing up your data.
USBDLM is not just targeted at businesses, though. You might find that you'd prefer your iPod to have its own drive letter, or perhaps the letter assigned to your mapped network drive is conflicting with the letter used for your USB drive.
You might be saying to yourself, "but you can change your drive letter in computer management within Windows, can't you?" - Yes you can, but when you connect a different hard disk drive or even restart the machine, Windows may forget (or clear this information from the cache) and re-assign the drive with a letter further down the alphabet. USBDLM will help resolve these conflicts.
Will USBDLM work on my PC?
Most probably, yes. USBDLM is compatible with Windows 2000, XP, Server 2003, Vista, Windows 7 and Server 2008. 64 bit support is also available.
How do I install USBDLM?
Installation is really simple. First of all, visit USBLM's website
Then, depending on whether you have a 32-bit or 64-bit operating system, select the appropriate install file. You can choose to either download a zip archive or the actual install package (msi). The easiest way is to just download and run usbdlm.msi. If you choose to download the zip archive you need to make sure you have an archive manager such as winzip or winrar installed prior to downloading.
After accepting any User Account Control prompts and finalising the installation, a new service will be created called USBDLM (highlighted below). You can check this by going to start > run > services.msc or going to the control panel and computer management > services. You will notice that the USBDLM service will be automatically started, and will always be running until you manually stop it.
Configuring USBDLM to work with your USB disk drives
First of all, you need to decide which drive letter is going to be assigned to each drive. I would advise using a letter from the middle of the alphabet, leaving letters from the start of the alphabet for system drives and letters from the end of the alphabet for network mapped drives.
Next, browse to the USBDLM directory, which will be C:\Program Files\USBDLM or C:\Program Files (x86)\USBDLM depending on which version of Windows you're using, and look for a file called USBDLM_sample.ini. This is the file where you tell the USBDLM service which disk drive to use and which drive letter to use.
In the scenario below, 2 x Western Digital hard disk drives both need to have the drive letter T assigned to them for the backup to run successfully. The drive letter will be retained regardless of which drive is used, or which USB port on your machine the disk drive is connected to.
*Note that the current version at the time of writing this article was v18.104.22.168 - the .ini file may look different in future and beta releases so be sure to read the documentation thoroughly.
As you can see from the .ini file, the only information specified is the drive letter; there is no mention of drive manufacturer, firmware revision or drive capacity. By default, USBDLM will assume the drive you are specifying has a USB interface, and is a removable drive. You can configure USBDLM even further if you wish, for example you could limit the amount of USB drives per drive letter, or you could specify a different connection type.
Once you've finished configuring the .ini file, rename it to USBDLM.ini (as above) or simply create a new file and leave the sample file as it is as a reference point.
Note: Every time you edit the usbdlm.ini file you will need to restart the usbdlm service for changes to take effect.