loader.conf

[gahn]

Thanks for the detailed information.

Best


--- On Fri, 4/10/09, Matthew Seaman <m.seaman at infracaninophile.co.uk> wrote:

> From: Matthew Seaman <m.seaman at infracaninophile.co.uk>
> Subject: Re: loader.conf
> To: ipfreak at yahoo.com
> Cc: "freebsd general questions" <freebsd-questions at freebsd.org>
> Date: Friday, April 10, 2009, 9:03 AM
> gahn wrote:
> > Hi all:
> > 
> > I have a machine with 2GB memory. in the file
> loader.conf, there is a line:
> > 
> > #hw.physmem="1G"                # Limit
> physical memory. See loader(8)
> > 
> > Could I remove the "#" and change that to
> "2G"?
> > 
> > Interestingly, the sysctl indicates the parameter of
> "hw.physmem" is not changeable.
> > 
> > Any guru here give me some enlightenment?
> 
> hw.physmem is a loader tunable: ie. you can only set it
> from the boot
> loader before the kernel is fully operational.  Once the
> kernel is running
> it can't be altered.
> 
> hw.physmem is designed to let you test running a kernel
> with less RAM
> than is physically installed in a machine.  Not having to
> pop the case
> and physically pull memory sticks out can be pretty useful.
>  It's not of
> general interest -- only for kernel and various other
> software developers
> in the main -- as the usual thing is to make use of all the
> RAM you have
> available or (in the case of 32bit machines) that the
> system is capable of
> addressing. 
> If hw.physmem is unset in loader.conf the kernel will
> automatically use all
> the memory available to it: this is the correct and
> desirable behaviour for
> the vast majority of systems.  For a 2GB machine, that
> means the system will
> use all the RAM that's installed.
> 
> 	Cheers,
> 
> 	Matthew
> 
> -- Dr Matthew J Seaman MA, D.Phil.                   7
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