I have a Pi 3 which I've wiped clean, and updated to Pixel; nothing else is running on it (correction, I loaded realvnc). I'm using the graphical interface, if that makes a difference. When I plug in a memory card reader with SD or CF cards inserted, they are automatically mounted to /media/pi/, which is OK, but I'm puzzled as to how that's happening. When I plug them in, I get a "removable medium is inserted" pop-up window, with a default action of Open in File Manager. What process is mounting these media?
I've searched here and elsewhere, and have not found a definitive answer, or one that appears to be the case for my pi. I've looked at /etc/fstab and etc/udev/, and neither of those shows an entry for automounting USB. I'm still figuring out /etc/systemd, but I'm not seeing an obvious rule there either. What am I missing? This seems like it would be reasonably useful knowledge for pi/linux newbies.
Also, when I plug in a USB "thumb" drive when the pi is already booted, it is not auto mounted, unlike the card reader USB device. If I boot with that USB drive connected at power up, it is mounted, which to me would point to fstab, but again, no entries there that show any indication of USB.
To clarify/reiterate my question: When running the Pixel GUI on a Pi 3:
- What process is responsible for automatically mounting some types of USB media like USB memory card readers?
- What process is responsible for automatically mounting other types of USB media like USB thumb drives when (and only when) they are connected at boot time?