L</SPAN
> won't work without them.
    This situation is rare, however, among modern operating systems.
   </P
><P
>    When <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> exceeds one of the various hard
    <ACRONYM
CLASS="ACRONYM"
>IPC</ACRONYM
> limits, the server will refuse to start and
    should leave an instructive error message describing the problem
    and what to do about it. (See also <A
HREF="server-start.html#SERVER-START-FAILURES"
>Section 17.3.1</A
>.) The relevant kernel
    parameters are 