That's right. DPS wasn't used for handling input events, or implementing the user interfaces widgets, which instead were implemented in Objective C running in another client process (usually running on the same machine), instead of PostScript running in the window server. DPS didn't handle events with PostScript in the DPS window server. Instead, it would ping-pong events over the network from the window server, to the Objective C client, then send PostScript drawing commands back to the window server. (Typically generic low level drawing commands, not a high level application specific protocol.)
So NeXTSTEP suffered from the same problems of X, with an inefficient low level non-extensible network protocol, slicing the client and server apart at the wrong level, because it didn't leverage its Turing-complete extensibility (now called "AJAX"), and just squandered PostScript for drawing (now called "canvas").
So for example, you couldn't use DPS to implement a visual PostScript debugger the way you could with NeWS, in the same way the Chrome JavaScript debugger is implemented in the same language it's debugging (which makes it easier and higher fidelity).
>The Shape of PSIBER Space: PostScript Interactive Bug Eradication Routines — October 1989
>Abstract
>The PSIBER Space Deck is an interactive visual user interface to a graphical programming environment, the NeWS window system. It lets you display, manipulate, and navigate the data structures, programs, and processes living in the virtual memory space of NeWS. It is useful as a debugging tool, and as a hands on way to learn about programming in PostScript and NeWS.
So NeXTSTEP suffered from the same problems of X, with an inefficient low level non-extensible network protocol, slicing the client and server apart at the wrong level, because it didn't leverage its Turing-complete extensibility (now called "AJAX"), and just squandered PostScript for drawing (now called "canvas").
So for example, you couldn't use DPS to implement a visual PostScript debugger the way you could with NeWS, in the same way the Chrome JavaScript debugger is implemented in the same language it's debugging (which makes it easier and higher fidelity).
https://medium.com/@donhopkins/the-shape-of-psiber-space-oct...
>The Shape of PSIBER Space: PostScript Interactive Bug Eradication Routines — October 1989
>Abstract
>The PSIBER Space Deck is an interactive visual user interface to a graphical programming environment, the NeWS window system. It lets you display, manipulate, and navigate the data structures, programs, and processes living in the virtual memory space of NeWS. It is useful as a debugging tool, and as a hands on way to learn about programming in PostScript and NeWS.