1 Oct
2017
1 Oct
'17
4:37 a.m.
To understand the Linux sysfs, you have to understand what problem
they are trying to solve. It is self inflicted, but it solves a
problem in a way the community values. Because the kernel is an
independent project versus libc (glibc, musl, Bionic, etc), and
because the base system is from others as well (coreutils, busybox,
systemd), Linus has become fanatical about ABI stability. The simple
text interfaces allow the kernel to change haphazardly without much
planning, and still retain binary compatibility. In terms of code
churn and needless KPI proliferation, Torvald's "masturbating monkeys"
insult toward OpenBSD holds up pretty well for his own crew :)
Operating systems (using subtle terminology that excludes "Linux"
without more specification) don't have that problem.
I haven't played with Plan9 at all. Read some code, the TCP stack was
cute but unrealistically simplistic. I need to take it for a spin.
Regards,
On Sat, Sep 30, 2017 at 2:56 PM, Bakul Shah <bakul(a)bitblocks.com> wrote:
On Sep 30, 2017, at 1:29 PM, Kevin Bowling <kevin.bowling(a)kev009.com> wrote:
I seem to recall proc is loosely deprecated in
Linux anyway in favor
of sysfs. GregKH mentioned people misuse both, for instance making
them output pretty histograms instead of simple text values, that
defeat the fundamental design tenants of these interfaces -- which is
to try and maintain a stable API.
One thing I think Linux did pretty well is the
whole object
orientation in C thing with kobject, and that nets you automatic sysfs
directories and nodes for pretty much everything.
The Linux /sys fs is truly bizarre. On a RaspberryPi running Linux 4.4.21+:
$ find /sys | wc # total entries
11448
$ find /sys -type l | wc # count of symlinks
1077
$ find /sys -type f | wc # count of "regular" files
8931
I am not sure exposing most everything via a namespace in this
manner is such a good idea (or at least in "good taste" :-)
Interfaces should be lean.
Similarly the /proc fs is quite strange. Why does it have any
non process subdirectory?
$ echo /proc/[0-9]* | wc -w # count of processes
142
$ echo /proc/[^0-9]* | wc -w # count of non-process directories
58
Compare:
Linux (raspberryPi + X windows):
$ echo /proc/[0-9]* |wc -w # how many processes
142
$ find /proc/[0-9]* | wc -l # how many proc related files+dirs
66153
FreeBSD (10.3 amd64+zfs+4 lightweight jails):
$ echo /proc/[0-9]* | wc -w # how many processes
123
$ find /proc/[0-9]* | wc -l # how many proc related files+dirs
1075
Plan9 (mostly quiescent):
$ echo /proc/[0-9]* | wc -w
64
$ du -a /proc/[0-9]* | wc -l
1235
Anyone feeling sad about /proc in FreeBSD should consider
the alternative!