[comp.emacs] Need info on "unexec

deg@drutx.ATT.COM (GillespieD) (06/26/87)

I've heard mention of "unexec"ing either GNU or Goslings
emacs to speed up invokation.  Can someone explain what 
this is, and how to do it?

	ihnp4!drutx!deg
	Don()Y

ron@topaz.rutgers.edu (Ron Natalie) (06/27/87)

Unexec is a routine that causes the EMACS to write it's current memory
image to disk.  Much of EMACS start-up time is devoted to reading in
and parsing the lisp extension packages (no one uses non-extended
EMACS).  Hence, you can decrease the startup time by writing the
memory image after all the baseline lisp has been loaded and parsed.
This is rather architecture specific, but has been done for a variety
of the machines.  GNU EMACS relies on it much, later UniPress
releases have optimized things so that it really doesn't make that
much of a difference, but it really depends on your machine speed.

-Ron