Most Linux can be run from a "Live" CD/DVD/USB media, without installing anything on the computer's hard drive
- desirable for evaluation of Linux on computers having Windows installed, where inexpert installation could overwrite Windows
- the Windows disk could be electrically disconnected, as an added precaution
- enables unknown Linux to be evaluated for functionality & ease of use
- NB any software will take relatively long to load and be relatively slow to run in this mode
- SD (or microSD) card, of Class 10 or better rating, in a SD-USB reader will load software many times faster than a DVD drive.
Live CD/DVD/USB can be created via most operating systems, using files that are mostly free to download from the Internet. See: Using dotISO Files