Improving ext4: bigalloc, inline data, and metadata checksums
Posted Dec 2, 2011 23:40 UTC (Fri) by walex
In reply to: Improving ext4: bigalloc, inline data, and metadata checksums
Parent article: Improving ext4: bigalloc, inline data, and metadata checksums
As to udev some people dislike smarmy shysters who replace well designed working subsystems seemingly for the sole reason of making a political landgrab, because the replacement has both more kernel complexity and more userland complexity and less stability.
The key features of devfs were that it would populate automatically /dev from the kernel with basic device files (major, minor) and then use a very simple userland daemon to add extra aliases as required.
It turns out that after several attempts to get it to work udev adds to /sys from inside the kernel exactly the same information, so there has been no migration of functionality from kernel to userspace:
$ ls -ld /dev/tty9
crw--w---- 1 root tty 4, 9 2011-11-28 14:03 /dev/tty9
$ cat /sys/class/tty/tty9/dev
And the userland part is also far more complex and unstable than devfsd ever was (for example devfs did not require cold start).
And udev is just the most shining example of a series of similar poor decisions (which however seem to have been improving a bit with time).
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