From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 In-Reply-To: <6bfc22f33651561fce4dc12172b8a682@quanstro.net> References: <3aaafc130904172104o30fb339fn4b3490cb60acbdbc@mail.gmail.com> <6bfc22f33651561fce4dc12172b8a682@quanstro.net> Date: Sat, 18 Apr 2009 01:57:47 -0400 Message-ID: <3aaafc130904172257g57bae1apbcff37de5461a604@mail.gmail.com> From: "J.R. Mauro" To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Subject: Re: [9fans] Plan9 - the next 20 years Topicbox-Message-UUID: e53c4494-ead4-11e9-9d60-3106f5b1d025 On Sat, Apr 18, 2009 at 12:16 AM, erik quanstrom wr= ote: >> On Fri, Apr 17, 2009 at 11:37 PM, erik quanstrom = wrote: >> >> I can imagine a lot of problems stemming from open files could be >> >> resolved by first attempting to import the process's namespace at the >> >> time of checkpoint and, upon that failing, using cached copies of the >> >> file made at the time of checkpoint, which could be merged later. >> > >> > there's no guarantee to a process running in a conventional >> > environment that files won't change underfoot. =A0why would >> > condor extend a new guarantee? >> > >> > maybe i'm suffering from lack of vision, but i would think that >> > to get to 100% one would need to think in terms of transactions >> > and have a fully transactional operating system. >> > >> > - erik >> > >> >> There's a much lower chance of files changing out from you in a >> conventional environment. If the goal is to make the "unconventional" >> environment look and act like the conventional one, it will probably >> have to try to do some of these things to be useful. > > * you can get the same effect by increasing the scale of your system. > > * the reason conventional systems work is not, in my opinion, because > the collision window is small, but because one typically doesn't do > conflicting edits to the same file. > > * saying that something "isn't likely" in an unquantifiable way is > not a recipie for success in computer science, in my experience. > > - erik > I don't see how any of that relates to having to do more work to ensure that C/R and process migration across nodes works and keeps things as consistent as possible.