sysvinit does not use memory for services it has already set up
only for a shell
thus is the good for memory constrained environments (only hard coded C or assembly would be better)
systemd is the opposite since it needs things that take up couple MB memory
If a system is so resource-constrained that systemd is too big, chances are that system is cut down so far that it likely doesn't include a classic init system at all. Such a device doesn't need flexibility, doesn't need different run-level structures, etc. All it needs is a simple script or binary that brings up an initial configuration and starts a handful of hardcoded services.
And this is more or less just a guideline. Notice how there's nothing on what's enabled/disabled by default. This is done on a per-package basis simply to keep packaging sane. It does not make sense to disable or enable something just because "that's the Arch way" when it might be completely stupid for that particular package.
In the case of this, I wouldn't be surprised if it was left off. netctl has always been available but it's not meant to be a one-all solution and can easily be left alone and even removed. In the case of this, it seems to do the opposite and defaults to using a tool that may not be necessary. But hey, if most people end up wanting it on by default, it will probably be left on by default. There's nothing in "the Arch way" or packaging guidelines to say otherwise.
For the record, this came up not because of netctl, but because of ALSA. See:
1) This is a bug, and Lennart agrees, although it doesn't seem to be a bug that's affecting many people, and there's a workaround.
2) If you don't think the ALSA daemon should be enabled by default on Arch, take that up with Arch. Nobody is forcing them to distribute systemd's defaults. But don't be surprised if Arch ignores you; I suspect they're quite satisfied that sound works out of the box.
2) If you don't think the ALSA daemon should be enabled by default on Arch, take that up with Arch.
ALSA "daemon" sounds so heavy. It's very simple tool that runs once in very early boot to restore the previous sound leves and the other runs once in the shutdown to save the current sound levels. There's similar tool for backlight and rfkill. There's a kernel command line option "systemd.restore_state=0|1" to disable this (it could apply only to rfkill and backlight though).
The context is that the 16 GIg figure I quoted is becoming typical for new mid level desktops. For getting a desktop up and running most of us are drowning in RAM. Wanting to be able to use a couple of meg of that for initialisation hardly seems unreasonable or overly self centred to me if that extra memory can make things faster, more reliable or easier to programme /configure.
Linus didn't create the kernel to improve Amazon's servers or to aid Google in taking over the world. He created it for the desktop, I'd like to see a desktop OS that can really compete with windows and Mac. SystemD is a long over due part of delivering that.
is it possible to configure my wpa2-psk connection via new systemd-networkd?if so,how?
i dont want to use netctl anymore.
i googled before this post but i only found wired, no wireless.
networkd does not support setting up wireless connections (or anything else on layer 2 for that mater (bluetooth etc)). However, if you manually configure wpa_supplicant (or bluez, if you are using bluetooth) to set up your wireless connection, networkd will discover when you are associated and set up DHCP for you just fine (this is what I do on my laptop).