- use clearer method names, comments; - define dtm usage info; - determine action by switch-case instead of if-else, because only os.Args[1] needs to be checked; - use time layout '2006-01-02 15:04:05.999' to format milliseconds; - change filenames dtmsvr/main.go to dtmsvr/dtmsvr.go; - simplify code; - use `()` to think less about operator precedence; xxx