See log in
A record of computer activity used for statistical purposes as well as backup and recovery. Log files are written by the operating system or other control program for such purposes as recording incoming dialogs, error and status messages and certain transaction details. Start and stop times of routine jobs may also be recorded.
Any program might generate a log file. An application may generate a log that the user can refer to if necessary or that may be helpful in the event of a failure. For example, an FTP program may generate a log file showing the date, time and source and destination paths for each file transferred. See data logging