of paper against the drum could ignite either the paper itself, or, in a dirty machine, the accumulated paper and ink dust in the mechanism. Whether this ever happened is not known; there are no reports of friction-related printer fires.

The line printer employed a series of status codes, specifically ready, online, and check. If the online status was set to "off" and the check status was set to "on," the operating system would interpret this as the printer running out of paper. However, if the online code was set to "on" and the check