 Early computers came with none—you had to give all the instructions to the computer with every program.  Then libraries of instructions were developed so that you could just include those.  As storage for programs grew, and computers became more complex, it be came necessary to develop operating systems.

 A piece of stiff paper that contains digital information represented by the presence or absence of holes in predefined positions.  Early computers used punched cards as the primary medium for input of both computer programs and data.

 DOS stands for Disk Operating System  An operating system (OS) is software that runs on computers and manages the computer hardware.  It also provides common services for efficient execution of various application software.  MS DOS was Microsoft’s branded version of DOS  There were plenty of other OS’s out in the wild, such as UNIX, OS/2, Amiga’s OS, and Apple’s OS  Introduction of the GUI (Graphical User Interface)

 What we currently refer to as an Operating System, is generally far more than just an operating system.  There are lots of operating systems out there running all kinds of devices, such as your cell phone, video game console, and web servers.  Steve Jobs of Apple: “To be innovative technological products, you need to develop both the hardware and the software.”