I noticed that I could remount my USB hard drive through terminal after I eject it by typing diskutil list to find the drive and diskutil mountDisk /dev/disk"X"...
So I tried to do the same with my SD card and my USB flash drive but...after I eject them, I cannot find them anymore through diskutil list.
I suspect this is because they are not "drive" until the system determines them as drives...which happens automatically when you plug them in - and the system remove those drives from the USB interfaces/SD card interfaces after I eject them.
So, the question is, how do I manually determine these USB interfaces/SD interfaces as "drives" so I can remount them. Thanks.