The OS is the Operating System. I know you knew that. There is some confusion between an OS and Graphical User Interface (GUI)... and for good reason... they have been mis represented!
A GUI is just that - a GUI. It allows the user to point, click and see pretty things. The GUI puts everything in sight to make it easy to get to as well as remember to do it... basically less to remember. Nobody likes the dreaded
C:>, it runs the mind blank. Hard to see what is under there.
The Operating System, on the other hand, manages the rest of the system. Devices, memory, input, output, etc.
GUI's have always been popular... in the begining, before Windows (Winders if you are from Texas), I wrote menu systems for users. Basically a file that produced a screen full of options along with a set of scripts. If a program wasn't listed on the screen, it was never used.
There are basically two operating systems on the personal computer. DOS and Linux.
is the operating system under windows. It has been completely absorbed within the GUI. DOS
, the PC version of Unix, comes in a miriad of varieties, flavors and complexities. There are GUIs that can be used on Linux (quite a few of them) or if you are like me, the command prompt is best.