Eric Seppanen <[EMAIL PROTECTED]> writes:
> On Thu, Feb 01, 2001 at 10:50:16PM -0500, Tyson D Sawyer wrote:
> > Eric Seppanen wrote:
> > >
> > > On Thu, Feb 01, 2001 at 06:21:46PM -0500, Tyson D Sawyer wrote:
> > > > Has anyone done any work loading an initrd image from linuxbios or
> > > > anything that might be related and useful?
> > > >
> > > I have a PLD paging a 4MB flash device, and I actually have both: I use
> > > initrd to load the root filesystem, and a block driver to reprogram the
> > > system. I prefer initrd for booting because if you don't mind your root
> > > fs being in ram you can compress the whole thing- I get 8MB worth of data
> > > in my root fs, stored in only 4MB.
> > >
> > > It's really easy. If you can load your filesystem image (or compressed
> > > filesystem image) into ram, it's trivial to get the kernel to notice it
> > > and use it. You just have to drop a pointer to the start of the image,
> > > and the size, into the kernel parameter table (same table that holds the
> > > kernel command line).
> > >
> > Ron says that he likes the block device driver better but I have done
> > some digging through the sources and the initrd option looks easier and
> > I really need to take the fastest option.
> >
> > Eric, do you have any suggestions on where in ram to load the compressed
> > ramdisk image? It looks like syslinux loads it just below top of ram,
> > or 0x????? (didn't write it down), which ever is lower. Is that the
> > best policy?
>
> Um, I'm not sure exactly. I loaded it at the very top of ram. I would
> hope that the kernel is smart enough to reclaim the memory for
> general-purpose use later, but I really have no idea.
I've been messing with it ramdisk quite a bit though not quite in
the linuxBIOS context.
Yes the kernel is smart enough to reclaim memory, and 2.4 is
even smart enough to reserve the memory from it's boot time
allocators. 2.2 isn't and on one system with 2.2GB of ram
placing the Ramdisk at only 16MB got me into trouble. So placing
the ramdisk as far from the kernel as you can is a good idea.
In the next couple of months I intend to get improve the linuxBIOS
bootloader so it presents the same interface as my kexec patches do
and then you can you my mkelfImage script.
I have done it once on the L440GX it was a bit of hack but it didn't
work too bad.
Eric
