More than a few Linux distributions have pulled up their stakes in the decades old System V method of booting and quietly moved to a better way of booting. Better, faster, easier to maintain, and less prone to problems. I say "quietly" not to imply that there haven't been announcements, banners waving, and proper cheers from some segments of the Linux user community, but to emphasize how little disruption has occurred and how little those of us who have been living in the slower-to-change Linux environments have had to pay attention. But the changes are nothing short of huge.
In a dramatic move toward reducing the boot time for Linux systems, two contenders for system start-up have emerged in recent years. One goes by the name "Upstart" (get it? -- "start up" with the syllables reversed). The other is called systemd (for system daemon). If you hadn't spotted a dramatic change in your Linux systems, you're probably using one of the more conservative Linux systems. The difference between RedHat and Fedora today might really surprise you.
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