cd and usb

the good in having a Os installed on either a usb or a cd is that it is not expensive. Also you can try a Os and if u dont like it u can use something else. Another reason why it is good to have it on a cd or usb
is that. Another reason why it is good to carry a Os on a usb or cd is that if your os crashes you can just boot from the usb or cd. The reasons why there are bad is cuz it really slow and you can save any work