Install DragonFlyBSD on 48 MB RAM

[Venkatesh Srinivas]

On Thu, Mar 1, 2012 at 7:22 PM, Thomas Nikolajsen
<thomas.nikolajsen at mail.dk> wrote:
>>So my question is: can I install DragonFlyBSD on my PC with 48 MB
>>RAM? And if it is possible, then what is the right way to do it?
>
> Yes that should be possible;
> you will have to setup a swap partition (e.g. 256MB) on your HD and
> enable it (swapon), before running the installer.
>
> 48MB is a rather low mem system, so you might not be able to run the installer,
> but you can do manual install of DragonFly, that way you will also learn the steps,
> see /README on install media; please use UFS; not HAMMER, it needs more mem.
> (http://gitweb.dragonflybsd.org/dragonfly.git/blob/HEAD:/nrelease/root/README)
>
> 48MB will not get you running big programs, only do small things,
> but it should work, see http://www.shiningsilence.com/dbsdlog/2012/02/28/9296.html.
>
> As some developers has expressed in this thread problems triggered by such
> a small amount of mem might not get 1st priority from them, but just file a bug if you do see such.
>
> Â -thomas
>

One of our developers tested with snapshots; it looks like the DMA
reserve commit is the one that made DF no longer run w/ 48MB. That
makes sense, as 16MB of physical memory is locked up by that commit.
You should be able to boot with a loader variable set to reserve less
physical memory.

We someday need a better physmem allocator; the 16MB reserve is a good
step, but a low-fragmentation allocator would be better.

-- vs;