> For the complete documentation index, see [llms.txt](https://sliu583.gitbook.io/blog/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sliu583.gitbook.io/blog/operating-system/untitled/ostep/intro.md).

# Intro

### Definition&#x20;

**Operating System:** the body of software that is in charge of making sure the system operates correctly and efficiently in an easy-to-use manner.

### The Crux of the Problem

* How to virtualize resources?&#x20;
* How to build correct concurrent programs?&#x20;
* How to store data persistently?&#x20;