Linux® is a UNIX®-like, open-source, operating system for computers.
An operating system is an infrastructure of language code that interfaces with the hardware of your computer system. It recognizes the hardware and makes it available to software programs so that the software runs smoothly on the computer. Software is written then, with the protocols of a specific operating system in mind. An operating system in turn generally only recognizes software that is written to interface with it.
Although UNIX® is the grand daddy of operating systems, the most recognizable example of an operating system for most users today is Microsoft Windows®. But there are key differences between Microsoft Windows® and Linux® operating systems.
For one, Linux® is an open-source operating system. This means the source code is publicly available for inspection and even improvement. The advantages of open-source products range from the benefits of creative input from programmers all over the world, to security. With the source code readily available in the public domain, open-source products can be vigorously tested by programmers all over the world. This is much more difficult with a closed system like Microsoft Windows® because the source code is not publicly available.
Another major difference is that Linux® is based on the UNIX® operating system, while Windows® is a proprietary or stand-alone operating system.
Many people who are considering switching to Linux® wonder if their current Windows® software will run on the system. The short answer is no. The operating system was not designed for, or intended to run Windows® software. That said, some free and paid interfaces provide various kinds of solutions for running Windows® software on Linux® machines with varying results. It is the hope of enthusiasts that people will switch to alternative software designed for Linux®, however, as more applications are written for the environment.
It is unknown how many Linux® users exist because registration is not required, but the number is estimated to be in the millions.
Linus Torvalds began building the kernel of this operating system in 1991 when he was an undergraduate student at the University of Helsinki in Finland. He continues to develop it with the help of volunteer programmers. Linux® licensing allows the user to freely copy and distribute the software with its source code.