Hello, mbk is using vfork instead of fork (file sources/mbk/mbk_sys.c). Reading the vfork manual, you can see that " BUGS It is rather unfortunate that Linux revived this spectre from the past. The BSD manpage states: "This system call will be eliminated when proper system sharing mechanisms are implemented. Users should not depend on the memory sharing semantics of vfork as it will, in that case, be made synonymous to fork."" Besides vfork doesn't exist on IRIX. Surprising, no ? Is there a -good- reason to maintain vfork in mbk ? Best regards, Pierre Nguyen Tuong.