[comp.sys.hp] Shared memory help on 800 series needed

hearth@Unify.Com (Donald S. Hearth) (06/16/91)

    Is there a way to configure the kernel on a HP 9000/800 series computer
    to define the maximum size of individual shared memory segments?  On
    a 300 series, you can use SHMMAX, but I have heard that this will not
    work on an 800 series.

				    Thanks in advance,
				    Don Hearth
-- 
***************************************************************************
*  Donald S. Hearth        *   address: hearth@unify.com                  *
*  UNIFY Corporation       *                                              *
*  Sacramento, CA          *   Go 49ers, A's, and LA Kings!               *

paul@prcrs.prc.com (Paul Hite) (06/17/91)

In article <ilns30t@Unify.Com>, hearth@Unify.Com (Donald S. Hearth) writes:
> 
>     Is there a way to configure the kernel on a HP 9000/800 series computer
>     to define the maximum size of individual shared memory segments?  

Well, the following shared memory parameters are available in the
configuration file:

shmmni          100;
shmmni is the max number of shared mem segments systemwide.

shmmax          0x4000000;
shmmax is the max size of a shared mem segment.
Warning: interacts with dmshm...change both at the same time.

shmseg          12;
shmseq is the mex number of shared mem segments per process.

All of these came from prcrs' configuration file.  prcrs is a 9000/850.

There is one issue that you will encounter with porting shared memory
stuff to the 800's.  Your shmat(2) call must specify NULL for shmaddr.
The 800's must be free to decide where in the address space to put the
segment.  But it will chose an address off in hyperspace.  You will never
have a shared memory/malloc collision.

Paul Hite   PRC Realty Systems  McLean,Va   paul@prcrs.prc.com    (703) 556-2243
    "We are trying to bring up an Air Traffic Control display on an X window 
      terminal and there seems to be some problems." -- from comp.windows.x