From mboxrd@z Thu Jan 1 00:00:00 1970 From: bqt@update.uu.se (Johnny Billquist) Date: Mon, 27 Feb 2017 22:06:10 +0100 Subject: [TUHS] Emacs and undump In-Reply-To: <86efyjpehy.fsf@molnjunk.nocrew.org> References: <31f9e532-c59a-2d3d-1e9b-cef9a216d68e@update.uu.se> <86efyjpehy.fsf@molnjunk.nocrew.org> Message-ID: On 2017-02-27 21:26, Lars Brinkhoff wrote: > Johnny Billquist wrote: >> But having the memory around for a program, even if it is not running, >> is actually sometimes very useful. If ITS could handle that, while >> treating them as separate processes, all associated to one terminal, >> and let you select which one you were currently fooling around in, >> while the others stayed around, that is something I don't think I've >> seen elsewhere. > > And it's not just a list structure, but a tree. You can e.g. start a > new DDT, which itself can have inferior jobs (subprocesses). Hmm. That sounds similar to TOPS-20 then maybe. >> So, Emacs does it once, and then saves the state at the point where >> you can start editing. But it does not mean that the memory is >> shareable. It's full of various data structures, and code, and that >> will change as you go along editing things as well. > > Much is sharable. There's a concept of purification (which also comes > from ITS). A purecopy() function is used in temacs to put read-only > data in a special memory area. That area will become sharable in the > dumped Emacs. There are definitely some shareable things, but you need to remember that even some pure, read-only data can be problematic in a shared segment, as not all people might even have that data loaded, even if the data itself is readonly. Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt at softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol