They are in virtual memory and presumably subject to the same swapping
policy as everything else.  There's supposed to be a shmctl( )  function to
lock it in physical memory, but it is described as "unimplemented."
Unfortunately, that's one of those functions that you just can't duplicate
in userland.

----- Original Message -----
From: "Steve Dirickson (Volt)" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, August 28, 2001 8:29 PM
Subject: Re: File in memory


> Don't forget the POSIX shmxxx() functions, which let you
> access shared memory *without* requiring PM:

Though I wonder if these functions really use hardware memory, as
opposed to disc-paged virtual address space. Especially since the 'size'
parameter of shmget() says that "The maximum shared memory area size is
256 megabytes." Sounds a little big for real memory.

* To join/leave the list, search archives, change list settings, *
* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *

* To join/leave the list, search archives, change list settings, *
* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *