An operating system is the main program that runs on a computer, underlying and controlling all other programs.
The operating system of the Macintosh, for instance, runs application programs and desk accessories, and handles the details of how programs talk to you. Other computers run different operating systems, almost all of which are less friendly than the Macintosh.
TOPS Terminal hides many of the details of other operating systems from you, by remembering descriptions for operating systems such as UNIXΓäó. This hiding means that you can perform common operations without recalling the details of how they are implemented on the computer you're talking to.
For instance, you can call a computer and identify yourself, see what files are on that computer, receive one of the files, and say goodbye to the computer. using the Macintosh's menus and dialogs without knowing anything about the operating system.
This usage of "operating system" is not exactly correct, from a technical perspective. In fact, what we are calling the operating system is the "shell program" or the user interface, rather than the underlying support software.
For instance, there is a listing for the operating system "Red Ryder Host", but Red Ryder Host is a program that turns a Macintosh into a dedicated bulletin board server using the Mac operating system. But it looks to its callers like a special-purpose operating system, from which the Mac-ness is hidden.
New operating system descriptions can readily be added by you or a guru. The descriptions include generic control keys, services providing structured operations, the operating system's convention for ending lines in text files, and what the current and parent directories are called.
To see operating systems, you must have the Full Menus preference set.
