From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <463D8BA4.40804@conducive.org> Date: Sun, 6 May 2007 16:02:44 +0800 From: W B Hacker User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.8.1.2) Gecko/20070221 SeaMonkey/1.1.1 MIME-Version: 1.0 To: Fans of the OS Plan 9 from Bell Labs <9fans@cse.psu.edu> Subject: Re: [9fans] speaking of kenc References: <54fc0f1102d30ae5933e78e2e391032f@proxima.alt.za> <463D648C.4040703@conducive.org> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Topicbox-Message-UUID: 5c973a6a-ead2-11e9-9d60-3106f5b1d025 Rogelio Serrano wrote: > On 5/6/07, W B Hacker wrote: *snip* >> > >> ... OR machine-coding the 'primitives' for your own virtual-machine >> to obviate >> the need for having to worry about it at all. >> > > i see. theres a good idea there somewhere. some sort of vm... highly > optimised. > > well it can be done. but to abstract all hardware, not possible. it > will be very complicated and dog slow. > Seems otherwise. See Xen, Qemu, VMware, L4 & descendents, Inferno - not to mention the long-running won't die revenue king of them all IBM's MV/VM. And 'abstract all' needs a virtual dual-ported area of RAM set aside and mapped where it has to be, interrupt handlign to go - not too much else. Dangerous in the 'wrong hands' but simple enough. or see what DragonFly is doing w/r hand offs for so-far-native-DFLY-only virtual kernels. There may be soem meat on that bone. Only a few of these get at all close to the hardware, yet the speed for the best of them (seldom the same answer in every environment) is more than 'good enough' to do a great deal of useful thigs - devel at the head of the list. I daresay there are few folks here who have not used them or come to appreciate them as time-savers vs rebooting 'hardware' native installs. Even so - hardware doesn't *necesarily* have to change - multicore and privilege separation are fairly recent additions to commodity (x86/AMD) silicon and by no means fully utilized by all comers. So there *could* be more of these written to run as direct 'native' hosts, and probably will be... But that doesn't really change the asm / C / whatever 'need set'. Just lets it be buried a little deeper under the covers. Still no one-size fits all, though. Bill