Thank you, that was entirely new history for me. From Wikipedia:
> MGR featured overlapped [...] windows and [...].
Took a while to see the strength of tiling window managers.
> MGR featured overlapped [...] windows and [...].
Took a while to see the strength of tiling window managers.
https://en.wikipedia.org/wiki/NeWS
which had the interesting idea of using PostScript to drive the display.
Tektronix had one with a "storage" scope that would retain (for a while, fading) a picture drawn once with a vector-steered electron beam. There was a graphics board to plug into a DEC VT100. HP had such a terminal. I think the VT100 card took the same codes as the Tek, but the picture would stay until erased.
Programs to draw graphics would need a driver layer to work on different terminals. If you were clever, the same code could drive an X-Y pen plotter, typically from HP. Good times!
You could buy a knife-pen and put rubylith in the plotter, and cut out circuit board optical masks, usually at 4x or more magnification. Rubylith was two layers of plastic, dark red and soft on clear and hard. The knife would cut just through the red layer. Peel off the stretchy red stuff where you didn't want traces, and send the rest to the PC board shop.
If you keep the screen buffer as (part of) the backing store for the pixels of windows, you also have to make drawing code clip to any overlapping windows. If you don’t, memory usage goes up again.
And memory could be tight. As an extreme example, the screen memory on an original Mac was about the same size as the amount of memory available to the running application.
It did overlapping windows, and the program was expected to re-draw the part exposed if you moved one.
The 512k version, or "Fat Mac" came out soon after, and was actually useful.