Not surprisingly, it looks a lot like Emacs (or vice-versa).
 - https://www.youtube.com/watch?v=o4-YnLpLgtk
The Symbolics UI looks&feels nothing like Emacs.
Zmacs is just ONE application on it. Applications are not Zmacs buffer modes.
The shown applications, Listener and Peek are not Zmacs buffers or windows. Neither one uses Zmacs buffers/windows.
If you look at the Listener application window:
* it has no terminal mode
* it has no minibuffer
* it has no meta-x commands
* it is fully graphical (postscript compatible drawing model)
* you can't split it
* it has no menubar
* it has no iconbar
* it has no modes, it is just a Lisp listener and a command interpreter
* it is not an editor window and not an editor buffer,
you can't edit the text printed to it
* for each output it remembers the Lisp objects
* for each input it can reuse the Lisp objects
* since it is a window, you can resize/move it
* you can only type commands and s-expressions to it,
and they will be parsed online
Previous comment (mine): https://news.ycombinator.com/item?id=7878679#7882337
Seeing a price of $1100 for a IIfx was pretty disorienting, when I was shown the invoice to a IIfx system I was using back in about 92, that was in the region of 8 - 10,000 GBP.
I guess the depreciation from '92 through Y2K accounts for that. Similar depreciation accounts for the $900 price tag on the 32 GByte dual E5-2690 workstation under my desk...