Re: /usr/include/linux and stuff

["Stephen J. Turnbull" <nospam [at] sk.tsukuba.ac.jp>]

>>>>> "Al" == Al Hudson <eah106 [at] york.ac.uk> writes:

    Al> On Thu, 17 Feb 2000, Stephen J. Turnbull wrote:
    Al> AFAIK, PCMCIA support for linux is done in the kernel now,
    Al> but there we go ;)

    >> cardmgr?

    Al> Dunno about cardmgr, that might be too userland, but certainly
    Al> I was under the impression 60-70% of the work is done in the
    Al> kernel now?

What work?  If you mean bit-flipping, 99.44% of the real work is done
in the kernel---of course, because PCMCIA is an overgrown device
driver at heart.  If you're talking about development, David Hinds,
who is not a member of the kernel team (and can't be for religious ==
licensing reasons) does almost all of the real work.

cardmgr is definitely userland, but it also must make direct kernel
calls (eg, to pcmcia_core.o!) because PCMCIA is not supported by glibc
and not standardized by POSIX.

You cannot get away from the need to mix the standardized OS calls
defined by POSIX, Unix9x, etc, which are implemented by glibc in
Linux, with direct calls to kernel services in the same program.
Since some of the kernel support is defined through macros and
typedefs, you have to include kernel headers that do more than simply
define the kernel entry points and prototypes.

glibc is getting pretty good about making these things fairly safe,
but there are still many places where a program/glibc mismatch is more
dangerous than a program/kernel mismatch.

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