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?
> >
> > An other approach would be to create a block device driver for my paged
> > 8Meg flash chip.
> >
> > Anyone have any thoughts as to which is a better approach? The
> > read-only characterisic of creating a block device driver isn't a
> > problem.
>
> 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).
>
> I really didn't have to create a block driver to reprogram the flash, but
> at the time when I wrote it I didn't know what was going to work well, so
> I was leaving my options open. Doing it over, I'd probably have just
> written a simple char driver to allow reprogramming.
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?
Since I also like the block device driver option and think it would be a
nice addition to the linuxbios tool set (though part of the kernel), is
that something that could be made available?
May the source be with you!
Ty
--
Tyson D Sawyer iRobot Corporation
Senior Systems Engineer Real World Interface Div.
[EMAIL PROTECTED] Robots for the Real World
603-532-6900 ext 206 http://www.irobot.com
