[predakanga]

The emacs startup hack is in it's use of a glibc function called "unexec", which essentially serializes the program's state into a single binary which can later be executed normally.

One of the big downsides (and the reason it became well known) is it's lack of portability, as it requires in-depth knowledge of the system's memory structures.

LWN article and previous HN discussion: https://news.ycombinator.com/item?id=11001796 Somewhat lower-level article that shines some light: http://emacshorrors.com/posts/unexecute.html