You can plug in any drive type to a USB port and it will work provided that the external drive actually works.
The down side here is that if you are planing on using this drive on a customers computer to recover their Data you need their computer to boot. You can not boot off an external USB Drive unless the computer supports this option and then you can not have a Windows install on the External Drive and have it work with all computers capable of booting off a USB Port.
As for a USB 2 being usable on USB1 this isn't a problem it is just slower than USB2 so it will take longer to move things across tot he External Drive.
With all the Data Recovery Software that I have ever used there are 2 distinct types one will rebuild corrupted Partitions Information and the other type recovers Data off a Drive that has either been formatted accidentally or has had data removed by accident or has lost it's partition Information.
In every case like this I use a External Enclosure and fit the customers Drive to this and then plug it into my computer and run the required application to recover whatever Data I can. Generally speaking the more that a drive is used after the loss of Data the less you can recover unless you are using some Forensic Recovery Application.
You also have to realize that the use of Software to recover Data limits you to only working with Working HDD's as any software is useless when the drive no longer works.
I'm not sure what you think is involved in Data Recovery but generally speaking you do not use External Drives to save data to unless it is a dedicated drive that is only plugged in to save data to. Even them you would be better off using a Firewire Enclosure as the Data Transfer is considerably faster than any form of USB is.
Col
