Date: Tue, 10 Apr 2001 02:08:26 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: bakul@bitblocks.com (Bakul Shah) Cc: tlambert@primenet.com (Terry Lambert), jmallett@newgold.net (Joseph Mallett), dkelly@grumpy.dyndns.org (David Kelly), bzdik@yahoo.com (Bzdik BSD), freebsd-chat@FreeBSD.ORG Subject: Re: Clash of Titans - Tale of two Morons Message-ID: <200104100208.TAA26155@usr01.primenet.com> In-Reply-To: <200104092303.TAA20542@valiant.cnchost.com> from "Bakul Shah" at Apr 09, 2001 04:03:07 PM
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> > I'm not terribly impressed with L4. Their "no commercial use" > > license doesn't help my opinion any. > > Are you saying you are not impressed with L4's technology or > its licence? If the latter, you should look at Fiasco as it > implements the same API and is under GPL. It's technology. It's interesting that Fiasco appears to address all of the issues I had with L4. Thanks for the pointer. IMO, there's no reason to go with L4, since it can't support hard RT. For anyone else: http://os.inf.tu-dresden.de/fiasco/ > > At one time, I got pretty deep into the bowels of Chorus, > > which I fond to be very impressive (I've seen it running on > > a 1024 node multiprocessor). > > Yes indeed. I failed to mention it. I'd like to get my > hands on a Usenix winter '91 paper by Chorus people about > ukernels and unix. We ("We" was "Novell/USG" back in 1993) had NetWare and SVR4 running at the same time on top of Chorus. > > Given my druthers, I think Inferno is better than Plan9, as an > > example microkernel. > > I believe calling either os a microkernel will rile the Bell > Labs guys mightily!:-) But plan9 does seem very nice, > elegant, modular and quite simple. Inferno runs on top of > Plan9 (whether it runs natively as well I do not know). This thread started with someone claiming NT was a microkernel architecture. Unlike the Mach folks, I judge "micro" by size. 8-). > `given my druthers'. Does it come from "I'd rather"? Yes; usually, I avoid colloquialisms like that, but it seemed to fit the situation. > > I think that the licensing costs for both, as well as the yearly > > subscription renewal requirement, are why neither are gaining > > any real ground. > > Plan9 has been open-sourced for a while now. See > plan9.bell-labs.com. Too bad it was not open sourced 10 > years ago when it could've had the impact it deserves. > Judging from reading comp.os.plan9 now and then I get the > feeling plan9 is slowly winning converts. Inferno has been > transferred lock, stock and barrel to Vitanuovo. Yes, there are a couple of companies in the Silicon Valley area that are using it for their embedded system OS. Given the partitioning it enforces, the biggest complaint I've heard is that you have to drag things like strcpy() around with you wherever you go, which is not pretty. > > That's what the Lites project was all about. Unfortunately, > > the only really good microkernel implementations out there are > > very expensive closed source products. > > Fiasco is open. If you don't like it, L4 interface is simple > enough to reengineer from scratch relatively straight > forwardly. Well, I don't like the license, but the GPL is a lot better than the one on L4. > QNX is not free but can also serve as a good > model for what to factor out in a ukernel. But just porting > FreeBSD on top of such a kernel wouldn't be worth it. One > would have to tear apart intertwined modules and reduce their > interdependencies, simplify and thereby generalize various > subsystems and so on. Probably better to start from scratch, > build a framework and start implementing syscalls and > reintroduce code (treat FreeBSD as a collection of very > borrowable code fragments). I know, a lot of handwaving! I was really disappointed that FreeBSD never really bit the hard RT bullet, back when there was opportunity for it to do so. When John Dyson went off on his "new kernel" crusade originally, the reason I didn't participate was that it wasn't going to support hard RT. I just didn't really see the point, unless it was going to be able to do something that the current kernel could not, and lacking RT is the number one deficiency in FreeBSD, in my opinion. The problem with FreeBSD is that a lot of the lower level code is not deterministic with regard to running time. People will now argue endlessly about whether PC hardware can run Hard RT, I'm sure. > On the other hand plan9 seems like an eminently usable > system. Just imagine, you can mount tarfiles, zipfiles, > mailbox, dump tapes and so on as filesystems and (from what > I hear) it is easy to create a fs server for any such > collection of objects. I'll have to find out for myself.... You can do the same thing in FreeBSD, fairly trivially; I don't see how it's much different than portals; someone was complaining the other day about FreeBSD not having the Windows "control panel" feature, where you are not actually looking at a filesystem object, you are looking at a DLL loaded into your shell as a shell extension; I pointed out portals and got back "Oh.". 8-). Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
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