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I would like to read up on os X kernel parameters. I can find them listed, but where can I find the meaning of them?

For example this parameter

net.alf.loglevel: 55  

which are not in the man pages , for either BSD or osX.

How do people know what to set them to?

EDIT: I have found this link. It has helped me a lot.

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up vote 1 down vote accepted

The only real way to get all kinds of information about kernel parameters is to read the includes that those variables come from, in Mac OS X the list starts with

  • sys/sysctl.h: definitions for top level identifiers, second level kernel and hardware identifiers, and user level identifiers
  • sys/socket.h: definitions for second level network identifiers
  • sys/gmon.h: definitions for third level profiling identifiers
  • vm/vm_param.h: definitions for second level virtual memory identifiers
  • netinet/in.h: definitions for third level Internet identifiers and fourth level IP identifiers
  • netinet/icmp_var.h: definitions for fourth level ICMP identifiers
  • netinet/udp_var.h: definitions for fourth level UDP identifiers

It's a though read! :)

Also there's no standard way of tuning all these kernel parameters, everyone has different needs and Mac OS X will come preconfigured with values that'll meet "most" but still will leave some people with the need to tweak it, as you want to.

What I normally do if I want to tweak a kernel parameter I don't know much about is to Google it up, read as much as I can about what it does and what other people are doing and why, and from there try a value that can work from me.

Sorry that this is not the easy answer you were looking for, but I hope this will help you find the answers quickly :)

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sigh I was getting that impression. Time to bust out ctags. The thing is that the application firewall is undocumented for some reason... and the man page does not tell you where it's defined! – chiggsy Feb 10 '11 at 15:55

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