/ : root directory, it is the parent of EVERYTHING
/boot : holds files/directories related to booting the system (grub, initrd, vmlinuz, etc)
/var : contains variable files that change fairly 'often'
/usr : contains user accessible programs/info (libraries, documentation, binaries, etc)
/home : contains home directories of all users
/swap : I've never seen swap mounted as a filesystem b/c normally it acts as virtual memory
your software is probably in /usr somewhere