From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: From: erik quanstrom Date: Sat, 12 Aug 2006 15:07:35 -0500 To: 9fans@cse.psu.edu Subject: Re: Re: [9fans] APE fork() In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Topicbox-Message-UUID: 9e3e2d80-ead1-11e9-9d60-3106f5b1d025 i couldn't find the references to vfork i was looking for quickly with google; they were lost in vast arguments about vfork bugs. - erik On Sat Aug 12 14:54:40 CDT 2006, forsyth@terzarima.net wrote: > > I always thought vfork was introduced because > > copy-on-write hadn't been invented yet. > > > > It's the only logical explanation. > > no, it was because they chose not to implement copy on write. > it had been invented long before that. > in fact, i found copy on write at least as easy to do for unix > as the grunge required for vfork (and it was more generally useful). > on some architectures you need to use copy on reference. > their paging data structures might have made it more difficult, i suppose; > they had them upside down compared to unix's requirements. > > vfork also was specified so that if you relied on the sharing > except to implement a non-sharing fork, the effect was undefined.