[OLPC-devel] just verified: 2306 + olpc + linux kernel works.

[Marcelo Tosatti]

On Fri, May 26, 2006 at 02:46:22AM +0200, Carl-Daniel Hailfinger wrote:
> Marcelo Tosatti wrote:
> > On Thu, May 25, 2006 at 05:22:18PM -0600, Ronald G Minnich wrote:
> >> So we're three, right? Wow, Do you think once usb is in we will still be 
> >> under (512-64)*1024? This is pretty cool.
> > 
> > Taking into account that the real boot loader shall contain
> > 
> > - wireless firmware
> > - wireless driver
> > - IPv6 stack
> > - userspace code to talk over network (DHCP, TFTP, etc).
> > - framebuffer driver + nice graphical interface (images).
> > - USB
> 
> This is suicidal. Can we move parts of the boot loader to
> the file system? I think about a design like:
> ROM: LinuxBIOS + minimal kernel with JFFS2 + lightweight USB
> disk: graphical splash screen, all networking, full USB
> 
> This way, recovery via USB would still be possible, but in
> normal operation the bootloader would already depend on the
> file system. So "unbricking" would easily be possible even
> if somebody managed to overwrite the whole file system.
> 
> Thoughts?
> Carl-Daniel

Carl,

One point is that USB devices are not common amongst users of OLPC
machines: way too expensive.

Second point is that shipping 1MB flash is an option, as I have been
told.

To me it sounds like a worth tradeoff: additional cost of 1MB flash
by gaining complete HW independency on recovery (you need a nearby
machine to recover, sure, but that should be a common scenario, unlike
availability of USB storage devices).

Having a figure of how costly the 1MB flash is compared to 512KB would
be very good to help the design of the bootloader...

This issue has not been thoroughly discussed yet, and it should.