Date: Fri, 2 Jun 95 11:58:45 MDT From: terry@cs.weber.edu (Terry Lambert) To: spaz@u.washington.edu (John Utz) Cc: dbaker@Concorde-Mail.NeoSoft.COM, hackers@FreeBSD.ORG Subject: Re: FreeBSD on 286? Message-ID: <9506021758.AA26773@cs.weber.edu> In-Reply-To: <Pine.OSF.3.91j.950601234724.23239A-100000@saul3.u.washington.edu> from "John Utz" at Jun 1, 95 11:59:04 pm
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> Ahhh, terry, i was hoping u would way in on this one... :-) I been set up. > Hokay, we have established that this guy would be better of with > a 386 and 4 megs as opposed to a 286 and 8 megs,, right? No question, if what he wants is to run what FreeBSD currently has. > > The MACH VM system requires a PMMU; there are also assumptions in the > > swap, shared library, mmap, and linker that support this supposition. > > This dovetails neatly with a question i have about this. It is my > understanding that one of the reasons we have i*86BSD variants is that in > addition to the ability to become 4 little seperate 8086's ( which we > dont use, right? ), the 386 was the first cheap cpu to support a hardware > page table, does our kernel make use of this? We don't use the VM86 (thanks for bowing to my hobby horse 8-)), and yes, the ability to do virtual memory is more like it. And yes, there is use made of the page table. 8-). > exaclty which mac is this? They seem to be some real cheep used > ones around here, and i would love a 2nd unix box You'd have to look up MacBSD to be sure. A 68020 with a PMMU or a 68030 is supposed to work -- specifically, an SX30. The 040 was (last time I checked) in need of different memory management primitives, so it didn't work at the time. Not to mention that Apple doesn't document bus or device interfaces hardly at all (or I'd have ported to their PPC when it came out, come hell or high water -- I think it's a *very* sexy processer). > didn't linus' first effort get created on a 286? Not as far as I know. Minix was on the 286. Linus wanted a POSIX system. Maybe you are thinking of Minix? > > I've considered back-porting a simpler VM system, but the work would > > not be worth the effort (I don't even own anything less than a 486 > > except real old hardware, and I already have SVR2.3 for my Amiga > > 1000 with 68010) > > 68010? 68010? you are kidding! I had a class where we built stuff with > 68010's > > is there anything still available that runs on these mega cheap > amigas? Lots of software -- Commodore is dead. > wanna part with the whole thing? Is it usable? No I don't want to part with it, yes, it's still usable, and no, I don't think my source license is transferrable (except to equipment I own). The point was just that it wouldn't be worth my time, since the only hardware I have that could benefit already has a UNIX OS running on it. I might get side benefit out of making overcommit switchable, but that's not really enough incentive. I have better hardware on the way that I'll spend my time on. 8-). Personally, if I were him and I were that attached to my 286, I'd find Xenix 2.1 for it. Probably cost him more that it would cost to upgrade the hardware so it could run a free OS. It's his call. Terry Lambert terry@cs.weber.edu --- Any opinions in this posting are my own and not those of my present or previous employers.
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