2nd instance of mysql closes/doesnt start no warnings/errors?

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http://serverfault.com – I have an external HD and i'd like to run a 2nd mysql instance on it. I used the windows installer to install/configure mysqld as a service on windows7. I took the my.ini from C:\Program Files\MySQL\MySQL Server 5.5\my.ini Then edited the port (client and mysqld), datadir and innodb_data_home_dir. After running this command "C:\Program Files\MySQL\MySQL Server 5.5\bin\mysqld" --defaults-file="f:/dev/my.ini" I found an error which was all about the innodb_data_home_dir directory not existing. After that I ran the command again. Mysqld simply starts up for a second then immediately closes (HowTos)