[LinuxBIOS] patch: extending LAR, and removing elf from linuxbios (it is not needed)

Peter Stuge peter at stuge.se
Thu Aug 30 00:06:50 CEST 2007

On Tue, Aug 28, 2007 at 05:47:11PM +0200, Carl-Daniel Hailfinger wrote:
> >>> a major/minor version in the LAR header?
> >>
> >> I generally hate versions. Think features, not numbers.
> > 
> > but then you have to handle the versioning, and figure out what
> > to do if it does not match, and .... Let's not do this.
> We simply could reserve some space at the end of the header and use
> that for future extensions without having to change a version
> number. Only if the extension needs changes in earlier fields of
> the struct we would have to change the MAGIC.

This works!

On Wed, Aug 29, 2007 at 10:04:26AM +0200, Stefan Reinauer wrote:
> Interoperability between different lar versions seems to be the
> quest for finding the best method of shooting yourself in the foot.
> Definitely a big issue and you can spend a looot of time on getting
> it done right.

It has surely been done many times before.

On Wed, Aug 29, 2007 at 10:12:24AM +0200, Stefan Reinauer wrote:
> if (lar_version > my_version) {
>         printf("Your image is too new. upgrade lar utility\n");
> if (lar_version > my_version) {
>         printf("Your image is too old. downgrade lar utility\n");
> if (lar_version != my_version) {
>         printf("Your image version and lar utility version do not match. Change either\n");
> Anything beyound the above is a waste of precious time imho.
> Let's not do migration paths for pre-pre-pre-pre-pre-production
> software.

Agreed - but the sooner we decide on a nice upwards compatible
protocol the sooner it becomes production software. ;)

Your suggestion is pretty similar to what BitTorrent uses and that
works fine. One bit per feature or even one bit to active a separate
extension protocol.


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