What is Linux?
Linux® is an open source operating system (OS). It was originally conceived of and created as a hobby by Linus Torvalds in 1991. Linus, while at university, sought to create an alternative, free, open source version of the MINIX operating system, which was itself based on the principles and design of Unix. That hobby has since become the OS with the largest user base, the most-used OS on publicly available internet servers, and the only OS used on the top 500 fastest supercomputers.
Perhaps the best thing about Linux is that it’s open source. Linux is released under the GNU General Public License (GPL). That means that anyone can run, study, share, and modify the software. The modified code can also be redistributed, and even sold, but must be done so under the same license. This differs greatly from traditional operating systems—Unix and Windows, for example—which are proprietary, locked-down, and delivered as-is and unmodifiable.
What can you do with Linux?
Linux can serve as the basis for nearly any type of IT initiative, including containers, cloud-native applications, and security. It’s at the core of some of the biggest industries and businesses in the world—from knowledge-sharing websites like Wikipedia to the New York Stock Exchange to mobile devices running Android (which is a specific-use distribution of the Linux kernel with complimentary software). Linux has grown over the years to be the de facto standard for running highly available, reliable, and critical workloads in datacenters and cloud deployments. It has multiple use cases, distributions, target systems and devices, and capabilities—all depending on your needs and workloads.
Microsoft has embraced Linux and open source in other ways, producing a SQL Server for Linux and open sourcing their .NET framework (.NET Core/Mono) so that any platform can run it, opening up the capability for Linux-using developers to make applications with that framework. By 2027, all SAP customers will be moving to SAP HANA—an in-memory, relational database management system—which only runs on Linux. As of 2017, 50% of the SAP market are Windows customers.
When it comes to cloud, even on Microsoft’s Azure, more than 60% of the images on the Azure Marketplace and nearly ⅓ of virtual machines are Linux-based. Meanwhile, Amazon Web Services and Google Cloud Platform offer up multiple distributions of Linux in their publicly available images.
Linux continues to be the operating system of the future, with more and more systems depending on its stability and extensibility.
SOURCE: https://www.redhat.com/en/topics/linux
ON WHAT HARDWARE DOES IT RUN?
Although originally developed first for 32-bit x86-based PCs (386 or higher),
today Linux also runs on (at least) the Compaq Alpha AXP, Sun SPARC and
UltraSPARC, Motorola 68000, PowerPC, PowerPC64, ARM, Hitachi SuperH, Cell,
IBM S/390, MIPS, HP PA-RISC, Intel IA-64, DEC VAX, AMD x86-64, AXIS CRIS,
Xtensa, Tilera TILE, AVR32, ARC and Renesas M32R architectures.
Linux is easily portable to most general-purpose 32- or 64-bit architectures
as long as they have a paged memory management unit (PMMU) and a port of the
GNU C compiler (gcc) (part of The GNU Compiler Collection, GCC). Linux has
also been ported to a number of architectures without a PMMU, although
functionality is then obviously somewhat limited.
Linux has also been ported to itself. You can now run the kernel as a
userspace application – this is called UserMode Linux (UML).
