Logbook

This is the etymology of computer logs. Captain's log is short for logbook

> The book so called because it recorded the speed measurements made by means of a weighted chip of a tree log on the end of a reeled log line (typically 150 to 200 fathoms). The log lay dead in the water, and sailors counted the time it took the line to play out. The line was marked by different numbers of knots, or colored rags, tied at regular intervals; hence the nautical measurement sense of knot

https://www.etymonline.com/word/log#etymonline_v_43590