I see the first three have already been answered. As for the fourth, I'm not sure what you mean by 'long'. If you mean lines of code in the body of the function then this is a meaningless question - you'll never hit any real-wworld limits. The only limit you really need to watch for in kernel code is the stack frame. This is only 8K or so under x86 Linux so don't allocate big static arrays for example. Best wishes David Gillies San Jose Costa Rica > 3) how long can a fonction be in difrent machines > (i86 ...) __________________________________ Do you Yahoo!? Yahoo! Hotjobs: Enter the "Signing Bonus" Sweepstakes http://hotjobs.sweepstakes.yahoo.com/signingbonus -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/