When it comes to operating systems, the first time I knew about operating systems was in college. If my memory serves, it was an essay in which Linux was introduced as a powerful, free and sophisticated operating system which can be an alternative of Windows, which had predominated in the customers' market then. Unfortunately, I was so narrow-sighted then that I didn't keep on learning about it when I even couldn't know how to install a Linux OS on my PC. But the impressive slogan was stamped in my mind.
After about ten years later, I am now a software engineer by trade. Knowing about OS is an essential skill. Though I had a lot job to do, I strived to learn how to use desktop distributions of Linux. However, it is acknowledged that Linux is free only if your time is free. It is such a sophisticated system that I should spend much time learning it. Presumably, it is effective to learn how to use Linux. As a matter of fact, I should learn from the basic level and the lowest level. Almost all the operating systems share the same designing principle as same as Unix.
In conclusion, time is precious for a middle-aged men like me so that I should start now before it is too late.