Re: [tlug] X11 Session Manager Setup

["Stephen J. Turnbull" <stephen@example.com>]

Curt Sampson writes:
 > On 2008-10-31 01:31 +0900 (Fri), Stephen J. Turnbull wrote:
 > 
 > > Actually, I've hacked on xsm...
 > 
 > Ok. I'm sorry.

Well, I am too---I implicitly made the same assumption about you. :-)

 > > OK, so you think you want real session management.  Why?
 > 
 > I'm not sure. I thought that this was something I should get for
 > free for putting in all this work to find out what the heck it even
 > is?

Well, good session management is expensive in terms of specification.
I think the XSM protocol has everything needed, it's really just a
matter of rather generic event notifications.  But how should the app
respond?

Take (X)Emacs as an example.  While GNU Emacs is faster than XEmacs,
it still takes a perceptible amount of time to start up.  So the
recommended way to use Emacsen is to start them up, and just leave
them running.  On a modern machine, you can accrete a *lot* of 2-20KB
documents in buffers before you run into memory problems!  So, OK, I
run desktop.el, an Emacs-specific session manager.  It gets rid of
uninteresting buffers (*Shell Command Output*, *warnings*, *scratch*,
*sent mail*, you get the idea), but if I have a session that's been
running for 3 months (not unusual), it may take ten minutes to start
up, especially if some of the buffers are remote files.

So good session management in Emacs implies substantially better
heuristics for trimming buffer count, and a UI to help the user do it
quickly.  We don't have good session management in Emacs ....  There's
not really a lot of reason for it, since people do leave Emacs running
for months.  It's not session management, it's disaster recovery.

And GNOME, well, despite Havoc's advertisement for Metacity ("a WM for
the adult in you"), AFAICT GNOME is aimed directly at the crown who
think of a computer as a fancy typewriter.  Nothing in GNOME seems to
actually be designed; it's all either accretions of brain bubbles
(which can be pretty useful, like Emacs ... oops, I digress) or copied
from Windows/CUA/Motif.  Not even close to Mac's Aqua in concept, let
alone implementation.

 > I can see all the interesting things than can be done within this
 > protocol definiton, but the standard thing is just, "can do 'switch
 > user'", I'm fine with that. I'm even fine with the new "here's two
 > different ways to specify which programs get run after you log in
 > thing." (It's annoying, but I live with many other similar annoyances.)

Like I said, spec'ing the thing's UI hasn't really been done.

 > ((Though if Emacs doesn't [save state], probably nobody does.))

Well, Emacs can save state, but it needs connfiguring, and XEmacs
doesn't support XSM yet.  Emacs may (especially in the GTK
configuration).  Firefox for sure does ("do you want to save your
tabs?")  I think xterm probably does, since (despite the "here bee
dragons" warnings in the code) it is the flagship example of x.org.