On Thu, 10 May 2007, Gilles Gravier wrote:

> How do I set a systemwide ulimit (I want it to be effective, amongst other
> things, for php scripts, run out of crontabs)... I want to set ulimit -d to
> something high (unlimited, first, for testing purposes).

ulimit -d is for data segment size

See the options(4) manual page. You can define this in the kernel with the 
DFLDSIZ and MAXDSIZ options.

The defaults on my system are:

proc.curproc.rlimit.datasize.soft = 268435456
proc.curproc.rlimit.datasize.hard = 3221225472

Which matches up with what I also see in my 
/usr/include/machine/vmparam.h.

  Jeremy C. Reed