Boot Log is a program that runs on OS-X to grab the user name you booted up as and saves a log in the user's prefs folder called 'boot log'. This log is added to every time the program is executed so it is suggested to make the program part of the startup items in a user's system preferences. The only known issue is that it currently does not save the file in a common place for global accesses across different users. It is suggested that you use 10.1 or later version of OS-X as the user name lookup routine doesn't work well with the earlier versions of OS-X. The source code is included.