Prior to 1977, FAT was not required for IAAF official timings. Times were recorded manually to one tenth of a second; three official timers with stopwatches noted when the starting gun flashed and when the runner crossed the finish line, and their median recorded time was the official mark. Some races also had an unofficial FAT, or semi-automatic time, often in conjunction with photo finish equipment. The first person timed at under ten seconds was Bob Hayes, who ran 9.9 s in April 1963 at the Mt. SAC Relays with an illegal following wind of . Hayes clocked another illegal 9.9 s (wind ) in the semi-final of the 1964 Olympic 100 m, with the first sub-10 FAT of 9.91 s. In the final, Hayes' official tenths time of 10.0 s was calculated by rounding down the FAT of 10.06 s; the backup hand-timers recorded 9.8, 9.9, and 9.9, which would have given 9.9 s as the official time if the FAT had malfunctioned.