As a follow up to my last post, I wanted to provide more detailed information about the kernel log. In my last post, I showed the console program with the kernel.log file showing a USB device with a serial number:
This is all well and good, but what are the three hex values after the serial number?
They are actually rather useful. If you look at the source code for IOUSBInterface::SetProperties from Apple you can see that the three values: 0x90c 0x1000 0x1100 are the Vendor ID, Product ID and the DeviceRelease number:
So in this case looking online at the most up to date database: http://www.linux-usb.org/usb.ids one can see that 0x90c (090c) is from Feiya Technology Corp. and 0x1000 (1000) is a Flash Drive and 0x1100 (1100) is the release for that flash drive.
As for the (non-unique) identifier label "FBF1011220604786", that is simply showing that the serial number is not necessarily unique because there is no specification that indicates they have to be. Apple is just making sure that nobody gets the wrong impression that they may not be unique.
[Update] Please see our Locating USB Device Connection Artifacts on a Mountain Lion Computer for updated information about USB device artifacts on a computer running Mac OS 10.8.