Eighth Edition and job control (was Re: UNIX Futures)

[Guy Harris]

> I think that a window should have both a logical and a physical size.
> When the user resizes a window, that would only change the physical
> size - the logical size would stay the same.  If the physical size is
> smaller than the logical size, the windowing system should put in
> scroll bars.

OK, imagine a text editor.  Assume that the logical size is the maximum size
of a window.  You use the scroll bars to slide the physical window over the
logical window.  Now what if you want to scroll the *editor's* window into
the *file*?  Can you use the same scroll bars?  I suspect it can be done,
but make sure your whizzo window system can do this.

So much for vertical scrolling.  What about horizontal scrolling?  I happen
to prefer an editor which truncates lines at the margin, rather than
wrapping them, but some people may prefer wrapping.  Such an editor has to
know about the physical size of the screen - wrapping at the boundary of the
logical screen seems a bit silly.

What about a system which displays a fixed amount of data - say N rows by M
columns of text, or a drawing of a certain size?  Such a system might very
well want to scale this display to the size of its window, so that you can
blow the display up by stretching the window.  (The Andrew system's terminal
emulator, which emulates a 24x80 Heath H19 terminal, does exactly that.)

What about a program which has a display consisting of a main display
subwindow, a command line, and a messages line, or something similar?  (For
two obscure little-used programs which use the screen in this way, let's
pick "vi" and EMACS.)  If I start up EMACS (or "vi") in a full-height
window, and then shut that window down to the Sun standard 34x80, your
scheme might very well put EMACS' status line and command/messages line
(mode line and minibuffer) outside the window.  This seems silly.  It would
make more sense to have the main display window be resized by EMACS, which
is exactly what does happen on a Sun.

I'm afraid this sounds like the putative benefits of not having something
like SIGTSTP - you might say that you "don't have to" modify programs to
know about being suspended, or having their window size changed, but what
this really means is that you *can't* modify programs to know about this,
even if doing so would give them a better user interface.  Sorry, but any
system that buys "conceptual elegance" at the expense of making the person
who uses the system had better be a LOT more conceptually elegant than a
system which is more pleasant to use if it's to interest me - especially if
I'm the person who has to use it.
-- 
	Guy Harris
	{ihnp4, decvax, seismo, decwrl, ...}!sun!guy
	guy at sun.arpa	(yes, really)