Robert P. J. Day wrote:
The difference is that closed source OS's rarely change their
driver interfaces, so it would be extremely unusual for
something that already works and I have put into production to
suddenly fail due to an update.
I find this an astonishing assertion. Surely the Linux kernel
interface changes reasonably often?
um ... no. the kernel *internal* interfaces may change, but the
interface that is presented to the outside world is very stable.
http://lxr.linux.no/source/Documentation/stable_api_nonsense.txt
That's fine if you believe that the linux kernel will always
include every device driver, filesystem, and feature you'll ever
want. Don't ask me to join you in that leap of faith (or
arrogance, or whatever it is that makes you think
interoperability is unnecessary)...
what are you babbling about, les? all i did was clarify the
distinction between the stability of the *internal* kernel
interface and that of the *external* kernel interface. i said
nothing whatsoever about driver support or interoperability.
Errr, what? How can you say that the internal kernel interface does
not relate to the drivers that use them?
errr ... did you actually *read* the document for which i provided a
URL, les? ***of course*** changing the internel kernel interfaces
will undoubtedly affect the drivers which have been written to those
interfaces.
Yes, I read it. That doesn't make it true, and my response applies.
> and when those interfaces change, ***of course*** those
drivers will have to be updated to conform to the new interfaces.
from the document above:
"Linux kernel development is continuous and at a rapid pace, never
stopping to slow down. As such, the kernel developers find bugs in
current interfaces, or figure out a better way to do things. If they
do that, they then fix the current interfaces to work better. When
they do so, function names may change, structures may grow or shrink,
and function parameters may be reworked. If this happens, all of the
instances of where this interface is used within the kernel are fixed
up at the same time, ensuring that everything continues to work
properly."
see how that works, les? when enough people in the kernel
development community decide that an internal interface needs to
change, everyone (theoretically) works together to make that
transition as seamless and trouble-free as possible. and (note well)
that all of that should be invisible to the outside world -- only
driver developers need care. so what's your problem? what exactly
bothers you about this process?
Exactly what I said before which apparently you didn't read. Neither
experience nor blind faith lead me to believe that Linux will ever
include all the drivers I might want. When Linus was just out of
college he might have used the lack of experience to justify not wanting
to freeze an interface because he might get it wrong. At this point I
no longer believe that excuse. Interfaces should be treated as
contracts among programmers that aren't whimsically ignored.
rday
p.s. also note, les, that if a given driver is in-tree, that driver's
author doesn't even need to know about this, since it's the duty of
those people making the change to *also* take care of all code that
calls that interface. did you seriously think that someone might
change an internal kernel interface and just leave all the broken
calls to it hanging around in the kernel source tree?
Yes, using fedora I have had things break frequently. If you don't
actually use an assortment of different hardware perhaps you haven't
noticed. Even if I only used Linux on common hardware today, I would be
concerned about depending on it and being unable to move to hardware
with only vendor binary drivers in the future should that be the best
hardware choice. And in my opinion this is the most significant reason
that the majority of computers today don't run Linux.
--
Les Mikesell
lesmikesell@xxxxxxxxx
