What is an operating system (OS)?
In the simplest definition, an operating system (OS) is a set of instructions (software) that controls some hardware providing an interface for the user. These instructions are layered over the kernel accessing the hardware directly and the command line interface (CLI) or graphical user interface (GUI) for the user (normally a human being) to interact with it. These instructions are coded using in different languages from low-level (like machine language and assembler) to high-level (like C++).
Operating systems have evolved from their early days and surprisingly most modern operating systems were made a good time ago like MVS (1964), Unix (1969), BSD (1977), DOS (1980), Macintosh (now known as macOS, 1984), Windows (1985) and Linux (1991).
In the past couple of years, a different approach to operating systems and management of resources uses thin-clients (commonly referred to as dumb terminals) accessing all shared resources from a server through a web browser — referred to cloud computing.
At the same time, computers have shrunk from huge machines that would fit in a loft like an IBM System/360 mainframe to machines that fit in your pocket like any of today's mobile phones. Computers are used worldwide for various purposes from web browsing to going to outer space (NASA).
This site takes a high level look at various operating systems used worldwide. It is merely my opinion, the result of my curiosity of computer systems and programming. As such, the sole purpose of VintageOS is to document my experiences of rebuilding old computer systems and their operating systems and to have fun while doing the latter — porn for nerds, the naked machine.
If you are interested in experimenting with any of the operating systems covered in VintageOS, you can create a VDI with VirtualBox (free) or similar application.