In computing, metric time became widely used because it is easy to use with computers. Unix time gives date and time as the number of seconds since January 1, 1970, and Microsoft's FILETIME as multiples of 100ns since January 1, 1601. VAX/VMS uses the number of 100ns since November 17, 1858 and RISC OS the number of centiseconds since January 1, 1900. (Each of these is not exactly linear, as there are some interruptions with leap seconds.)