OCD programmers and backwards compatibility :-).
Les Mikesell
lesmikesell at gmail.com
Mon Jan 29 04:16:16 UTC 2007
Dave Jones wrote:
> > So does that mean that maintaining compatibility with anything outside
> > that kernel developers' direct control is hopeless? Should anyone who
> > cares about that just switch to Solaris now?
>
> If you care about a kernel symbol remaining constant forever,
> then you're in for disappointment.
What I care about is the ability for independent third parties to
provide additional drivers that have a reasonable lifespan. And yes I am
disappointed that the kernel developers refuse to cooperate by providing
a stable interface.
> We do offer _some_ ABI guarantees
> with RHEL releases, but it's a ton of work to do so (even just a subset).
> Doing that for Fedora would require a lot of manpower which doesn't
> exist today. It also requires sacrificing certain upstream changes entirely,
> which makes for real pain when subsequent must-have fixes are implemented
> on top.
Yes, obviously any commercial offering is going recognize the customers'
needs and meet them or they won't have any customers. Unfortunately,
free projects don't have to care - they can break vmware, ati, nvidia,
etc's added value on whim. Why should they worry about the effect on
end users?
> This isn't about control, it's about long term maintainence.
No, forcing one team to do everything is not the way to do maintenance
in a way that scales or is even itself maintainable.
> If Linux had a stable in-kernel ABI, it would be a horrific mess
> to work on, and certain problems would just be completely unfixable
> in a clean manner.
Odd, then, that more popular operating systems have managed it in a way
that permits third party drivers for a vast variety of devices to work
unchanged for years.
> If you want to see some of the horror show that proves this, take
> a look at what happens to a RHEL release near end of life.
> By that point, large parts of it have deviated from anything that
> ever looked like upstream, because instead of taking upstream fixes,
> we've had to bend-to-fit fixes to work around ABI constraints.
It's not having an ABI that causes this problem. It is the fact that
the current kernel hasn't respected it.
> Thankfully, no RHEL release lasts forever.
Don't say that... Most of my machines are running Centos 3.x.
--
Les Mikesell
lesmikesell at gmail.com
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