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    SubjectRe: ANNOUNCE: User-space System Device Enumation (uSDE)
    Date
    On Tue, 28 Oct 2003 22:52:33 +0000, Greg KH wrote:
    > For SDE:
    > $ find . -type f | egrep '[.c|.h]$' | xargs wc -l | tail -1
    > 57328 total
    ...

    > For udev:
    > $ find . -type f | egrep '[.c|.h]$' | xargs wc -l | tail -1
    > 17632 total

    Here is a config file and a 41 lines shell script, that
    will populate /udev with all devices found via /sys.
    A version to add or remove only one file should be about
    the same size.

    ---cat /etc/makedev.conf---
    ttyS0 root dialout 0660
    zero root root 0666
    null root root 0666

    ---cat makedev---
    #!/bin/sh

    set -e

    DEV=/udev
    CONFIG=/etc/makedev.conf

    cd $DEV

    find /sys/class -name dev |while read A;
    do
    B=`dirname $A`
    B=`basename $B`
    MM=`cat $A|tr ":" " "`
    mknod --mode=0600 $B c $MM
    if grep -q "$B " $CONFIG
    then
    USER=`grep "$B " $CONFIG|cut -d" " -f2`
    GROUP=`grep "$B " $CONFIG|cut -d" " -f3`
    MODE=`grep "$B " $CONFIG|cut -d" " -f4`
    chown $USER.$GROUP $B
    chmod $MODE $B
    fi
    done

    find /sys/block -name dev |while read A;
    do
    B=`dirname $A`
    B=`basename $B`
    MM=`cat $A|tr ":" " "`
    mknod --mode=0600 $B b $MM
    if grep -q "$B " $CONFIG
    then
    USER=`grep "$B " $CONFIG|cut -d" " -f2`
    GROUP=`grep "$B " $CONFIG|cut -d" " -f3`
    MODE=`grep "$B " $CONFIG|cut -d" " -f4`
    chown $USER.$GROUP $B
    chmod $MODE $B
    fi
    done
    ---cut---

    So udev is 99% overhead?

    sure, it's fast and small, and has lots of features that I don't need.

    > SDE: 57328 lines
    > udev: 9090 lines
    shell script: 41 lines

    > that udev is suffering from "lack of maintainability and bloat" if you
    > really want :)

    bloat. lots of bloat. what is that tdb database for?
    filesystems are persistent. if you want to save space,
    create a tar file :-)

    > p.s. yes, I know lines of code is a horrible metric, and doesn't really
    > mean squat. I just want to point out the huge size difference between
    > the current state of udev and SDE, with pretty much identical
    > functionality from what I can tell.

    I agree. lines of codes is a horrible metric, and comparing a shell
    script that uses many external commands to a c application with
    everything build is makes absolutely no sense. but I wonder why
    the off the shelf machine needs a c applications, if all those
    external commands are installed anyway.

    Regards, Andreas

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