As impressive as it was at the time (and still is), a floppy is writable.
Booting from read only media and having a fully functioning OS was completely groundbreaking. Especially when you consider how much hardware was supported without configuration.
https://www.youtube.com/watch?v=K_VlI6IBEJ0
https://web.archive.org/web/19991128112050/http://www.qnx.co...