3 ms·

When you boot Linux, the init system loads the drivers you need, turns on your network connection, fires up the necessary system service and then loads the desk

When you boot Linux, the init system loads the drivers you need, turns on your network connection, fires up the necessary system service and then loads the desktop. Without an init system, you have no way to do anything. Actually I'm pretty sure it's udev that handles module loading these days (which isn't related to the functions of init(8) and process management, even if it's part of systemd now), or alternately one can use the kmod tools manually. This is a misleading interpretation in general. The init system (though really the process manager) starts the services to enable all these things. The simplest form is just a synchronous tool that exec()s binaries.

agumonkey 12y ago
Yes, so what systemd did differently is to reify a lot more of the machinery so you can define a reaction graph for these synchronous events.
amyjess 12y ago
> This is a misleading interpretation in general. The init system (though really the process manager) starts the services to enable all these things. The simplest form is just a synchronous tool that exec()s binaries. Even in traditional init systems, networking configuration is written into the init scripts themselves. For starting the desktop and udev, sure, the init script just starts a service, typically through start-stop-daemon, but the actual network configuration logic is in the init scripts.
- rlpb 12y ago
  > ...networking configuration is written into the init scripts themselves This statement may technically be true, but it is misleading about what component actually does what. It depends on where you consider the init system to end and the distribution's networking scripts to begin. On Debian and Ubuntu, the ifupdown package provides traditional networking configuration, and network-manager the "desktop roaming" networking configuration. They integrate with the init system like other services (and arguably a bit tighter) but they are still separate components. So yes - as you say the networking configuration is written into the init scripts themselves, but the init scripts are provided by the distribution's networking components, not by the init system component. And indeed the systemd switch in 15.04 - a replacement of init system - has happened but the networking configuration mechanism (ifupdown) remains. Both before and after the init system triggers the networking to be configured, but the init system is not the component that does the work.

agumonkey 12y ago

Yes, so what systemd did differently is to reify a lot more of the machinery so you can define a reaction graph for these synchronous events.

amyjess 12y ago

> This is a misleading interpretation in general. The init system (though really the process manager) starts the services to enable all these things. The simplest form is just a synchronous tool that exec()s binaries. Even in traditional init systems, networking configuration is written into the init scripts themselves. For starting the desktop and udev, sure, the init script just starts a service, typically through start-stop-daemon, but the actual network configuration logic is in the init scripts.

rlpb 12y ago
> ...networking configuration is written into the init scripts themselves This statement may technically be true, but it is misleading about what component actually does what. It depends on where you consider the init system to end and the distribution's networking scripts to begin. On Debian and Ubuntu, the ifupdown package provides traditional networking configuration, and network-manager the "desktop roaming" networking configuration. They integrate with the init system like other services (and arguably a bit tighter) but they are still separate components. So yes - as you say the networking configuration is written into the init scripts themselves, but the init scripts are provided by the distribution's networking components, not by the init system component. And indeed the systemd switch in 15.04 - a replacement of init system - has happened but the networking configuration mechanism (ifupdown) remains. Both before and after the init system triggers the networking to be configured, but the init system is not the component that does the work.