Learn in the textbookRepresentative Types of Operating Systems
DefinitionLinux is an open-source OS written from scratch on the model of UNIX, with its source code made public.
ExplanationIn 1991 Linus Torvalds released its core, the kernel, and developers around the world have improved it ever since. A package that bundles the kernel with the software it needs is called a distribution, and many kinds exist for different purposes. Many distributions are available free of charge, and it is widely used on web servers and other servers as well as in embedded devices.
AnalogyIt is like a public cookbook that anyone can read and add to: it takes an old restaurant's flavors as a model, and each shop circulates its own adjusted version.
Memory hookThe name blends its creator's first name, Linus, with UNIX, so the name itself shows it belongs with UNIX.