 No noticeable performance penalty over native FreeBSD programs has been noted when running Linux binaries , and , in some cases , these may even perform more smoothly than on Linux . However , the layer is not altogether seamless , and some Linux binaries are unusable or only partially usable on FreeBSD . There is support for system calls up to version 2 @.@ 6 @.@ 18 , available since FreeBSD 7 @.@ 0 . As of release 10 @.@ 3 , FreeBSD can run 64 @-@ bit Linux binaries . 
