I'm told to install ubuntu on my laptop for work in order to learn shell scripting. I've read the best way is to install ubuntu on a USB stick and partition my HDD. I'm curious how an OS is bootable from a USB stick? Is it literally just a small interface that can be put anywhere? This reminds me of a time I downloaded a game onto my USB stick, when I brought it to my friends house he told me it will run slow if I don't install it and only run it from the usb, is this different from running ubuntu from a usb? Will ubuntu be slow?