Rich Freeman posted on Sun, 21 Sep 2014 22:34:23 -0400 as excerpted: > On Sun, Sep 21, 2014 at 10:02 PM, Frank Peters > <frank.pet...@comcast.net> wrote:
>> There are things which are not system calls that could easily be >> changed. It is not too far fetched to consider a time if and when >> systemd became so popular and entrenched that the kernel would be >> hard-coded to pass control only to systemd and nothing else. > > That seems extremely unlikely. How many people ran anything other than > sysvinit as their init for the 15 years or so before upstart came along? > Making the kernel dependent on systemd would defeat the whole purpose > of having a separation between userspace and kernelspace. Agreed. There's far too many and too broad usages of the Linux kernel for that sort of hard-coding, at least without at least a kconfig option for it. Is android suddenly going to switch to systemd? Unlikely, and it's generally acknowledged to be the biggest usage of the Linux kernel out there these days, so hard-coding android breakage isn't going to happen. Plus even if it did, we're dealing with open source here and Google would simply patch that out and their own solution in as they do with a bunch of other stuff. And if google could do that, so could anyone else. Then there's the tivos and the embedded medical devices and the multiple automotive systems likely running their own little embedded Linux kernels. Hard-coding systemd for all of that? Not going to happen. As for the loss of the usb static device nodes, did you (Frank) file a bug about it breaking your userspace? That's one of Linus' most firm kernel rules -- you do *NOT* change the userspace/kernelspace API/ABI and break userspace. However, there's a known exception. Rather like the old philosophical question as to whether if a tree falls in the forest and nobody hears/sees it, did it actually fall at all, if nobody notices the userspace/kernelspace ABI breaking, did it really break at all? Unfortunately, for support for stuff like the big databases, etc, the big users all tend to be on enterprise distros with years-old kernels and sometimes the changes that break that don't get noticed for years simply because nobody running those apps is running anything close to current kernels, or if they do, they aren't reporting the problem. Bu the time the breakage is actually noticed and reported two years later, other userspace may depend on the new behavior and it can become a choice of which userspace to break, the newer stuff depending on the new behavior or the older stuff that was broken but that nobody noticed or reported for years. That can cause problems, particularly when those old and now broken userspace programs are big-dollar enterprise users, but sometimes it happens. And Linus and the other kernel devs are constantly pointing out that if they break userspace, report it as soon as possible so it can be fixed. Those who fail to do so, unfortunately very occasionally have to live with the resulting breakage, at least to some extent, tho they still go to rather extreme lengths to finesse things if and when they can. So if your userspace breaks due to a kernel change, report it as soon as you detect it and ask that it be fixed. Linus is very likely to make sure it happens. If you didn't do that, well... -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman
