I was wandering if that's even possible! The other day my hdd crashed and it got me into thinking what if I could install a full OS on a usb(not live os though) from my cd/dvd that I had. So i fired up my pc without a hdd and with a kali-i386 cd along with my 4gb usb drive. Sadly the installation halted at the installation step which I assume is because of the 4gb size(it's not enough ig). Apparently I dont have any plans on buying a new usb drive for now. So..is that possible!!! And have anyone actually tried it though!