A few days ago I was delighted to find out that it's not all that difficult to write an iso image to a USB without the help of a third-party program explicitly designed to do so. But the command (or program) that facilitates this - dd - puzzles me.
According to Wikipedia it's designed to copy and convert raw data, but honestly I find this definition very equivocal and vague. I understand that it lets you turn one piece of data into another, but what happens if the specified output file is too small to be turned into the specified input file?
dd if=giant_file of=tiny_file
Also, when I create a bootable USB with an image file, the USB attains a filesystem type of isofs, but if I write an archive or executable to the drive, it retains its regular filesystem type.
Any clarification of what the dd command really does or how it works on a lower level would be much appreciated. Thanks!