Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!mips!daver!tscs!tct!chip From: chip@tct.uucp (Chip Salzenberg) Newsgroups: comp.arch Subject: Re: Paging page tables Message-ID: <2699E08D.117A@tct.uucp> Date: 10 Jul 90 14:05:00 GMT References: <5796@titcce.cc.titech.ac.jp> <1990Jul6.160004.896@zoo.toronto.edu> <5813@titcce.cc.titech.ac.jp> Organization: ComDev/TCT, Sarasota, FL Lines: 30 According to mohta@necom830.cc.titech.ac.jp (Masataka Ohta): >Sigh..., It seems to me that I must explain AGAIN in this newsgroup >why vfork() is essential. "Essential" is pretty strong language. At best, you explain why YOU think vfork() is *valuable*. >So, perhaps, you know when a page need to be allocated >swap space. With copy-on-write scheme, a page need swap space >when the page is written something. This behavior is entirely consistent with other Unix resource management behavior. Programs do not begin by reserving swap space for all the storage they might need. Rather, they ask for memory as necessary. Likewise, during a fork(), a Unix process doesn't reserve swap space; it uses it as necessary. Perhaps you don't like this philosophy. Well, then, it seems you're using the wrong OS for your tastes. >>Forking large processes without needing lots more memory/disk just >>requires an intelligent implementation. Unfortunately, intelligent >>implementors are scarce. > >I admit that that is an elaborated implementation. But, in general, >elabolation should be considered vice in UNIX. "Intelligent" and "elaborate" are not synonyms. -- Chip Salzenberg at ComDev/TCT ,