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Is it correct to say that a shell runs inside the terminal? Or that it runs (as any process does) alongside it and happens to have its input and output connecte

Is it correct to say that a shell runs inside the terminal? Or that it runs (as any process does) alongside it and happens to have its input and output connected up to the terminal? I get that you don’t like pedantry, but this seems an important conceptual distinction that I (as someone who doesn’t know much about the internals of OSs) wouldn’t want to get wrong.

denton-scratch 3y ago
> Is it correct to say that a shell runs inside the terminal? Nope. We use the word "terminal" nowadays to refer to a piece of software that is a terminal emulator. But the thing being emulated is what used to be called a "dumb terminal", which was a piece of hardware that couldn't itself run user software. "Shell" is the odd man out among these terms; a shell is always a piece of software. A terminal isn't necessarily a text device. I remember graphics terminals by Tektronix and Apollo. I never saw a blit terminal, but those things existed too. On SystemV, the console was simply the privileged terminal. My memory is poor, but I seem to recall that (a) there could only be one console, which had to be connected to a specific port; (b) you could only become root if you were on the console. On some early computers, I believe the term "console" referred to the panel of lights and toggle-switches on the case of the processor. The switches could be used to control memory contents and processor state; so OG wizards were said to be able to e.g. "toggle in the bootloader from the console".
- xanderlewis 3y ago
  I thought so. My intention was more to subtly correct parent rather than to ask a genuine question. ...although I've learnt a bit more from your reply. Thanks! MacOS seems to still have something called Console which functions somewhat similarly to what you describe (the panel of lights and toggle-switches, rather than a two-way communication device).
- Izkata 3y ago
  I think of "console" as "point of interaction": it's the prompt that waits for input inside the shell, as well as those blinky lights on old hardware computers.

denton-scratch 3y ago

> Is it correct to say that a shell runs inside the terminal? Nope. We use the word "terminal" nowadays to refer to a piece of software that is a terminal emulator. But the thing being emulated is what used to be called a "dumb terminal", which was a piece of hardware that couldn't itself run user software. "Shell" is the odd man out among these terms; a shell is always a piece of software. A terminal isn't necessarily a text device. I remember graphics terminals by Tektronix and Apollo. I never saw a blit terminal, but those things existed too. On SystemV, the console was simply the privileged terminal. My memory is poor, but I seem to recall that (a) there could only be one console, which had to be connected to a specific port; (b) you could only become root if you were on the console. On some early computers, I believe the term "console" referred to the panel of lights and toggle-switches on the case of the processor. The switches could be used to control memory contents and processor state; so OG wizards were said to be able to e.g. "toggle in the bootloader from the console".

xanderlewis 3y ago
I thought so. My intention was more to subtly correct parent rather than to ask a genuine question. ...although I've learnt a bit more from your reply. Thanks! MacOS seems to still have something called Console which functions somewhat similarly to what you describe (the panel of lights and toggle-switches, rather than a two-way communication device).
Izkata 3y ago
I think of "console" as "point of interaction": it's the prompt that waits for input inside the shell, as well as those blinky lights on old hardware computers.