Brick Insurance

[ron minnich]

LinuxBIOS has a "brick insurance" policy which we have made heavy use
of in the supercomputing community. The operation is simple: two
copies of the BIOS, plus a set of CMOS variables and associated code
which allows for selection of a known-good, fallback BIOS, in the case
of a failed reflash operation. The code tests the integrity of CMOS,
the state of some other hardware, and then a bit which indicates if
the last boot succeeded; if any of the tests fail, the fallback BIOS
is booted. This fallback can be a very conservative BIOS which
provides what is needed to (e.g.) allow a reflash.

If our experience in the supercomputing world is any guide, failed
reflashes are quite possible. What can go wrong, will go wrong,
usually far from help.

Brick Insurance allows a reflash operation to fail, but still leaves
you with a usable machine, which can be a very nice thing to have.

We had not activated the LinuxBIOS fallback mechanism because linux as
bootloader was too large for two copies in one MB. But, so far, OFW is
< 512KB. It's pretty easy to turn on -- just a change to the config
file.

Question is, does OLPC want to look at this type of brick insurance?

thanks

ron