Sunday, 19 March 2017

How to Control Linux Start-Up Services and Daemons






Just booted up, but your system’s still feeling slow and sluggish? Linux runs many applications “in the background” that you might not even be aware of. Here’s how to take control of them.

We all know the drill: you hit the power button on your computer, wait for a bit, then come back to a nice-looking log-in. But what happens during that time? Old-school Linux users will remember the pages (and pages, and PAGES) of diagnostic messages that would scroll by. These messages contained info on drivers being loaded, file systems found, and different processes being started.

Look - Log-in

Let’s take a quick look at what transpires between “power-on” and “desktop log-in.”

When you turn your computer on, the BIOS loads. This is software provided by the hardware manufacturer (separate from the operating system) and contains settings on the device from which you want to boot your session.


BIOS - Settings - Passes - Computer - Disks

The BIOS, depending on those settings, passes control to one of the computer’s physical disks, specifically to its bootloader. While the bootloader can be set up to include configuration data, its primary job is to pass control on to an operating system. It provides an interface to select from among OSes if your computer has more than one. GRUB is the standard bootloader for most modern Linux distributions.

When a bootloader starts up a Linux operating system, the kernel (or the heart of the operating system) is loaded. This will link up to your hardware, and then it starts a single process we’ll call a start-up process.

Process - Turn - Processes - System - Server


This start-up process is in turn responsible for starting all the other processes in the system. This includes server applications (including the X Server process on which your pretty desktop log-in will appear), so-called “daemons” (programs that wait in the background for specific events, such as the CUPS printing daemon), and others (like...
(Excerpt) Read more at: MakeUseOf and www.longroom.com

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