Date: Mon, 16 Dec 2002 11:45:02 -0500 (EST) From: John Baldwin <jhb@FreeBSD.org> To: Alex <akruijff@dds.nl> Cc: current@FreeBSD.ORG, Johnson David <DavidJohnson@Siemens.com>, phk@FreeBSD.ORG Subject: RE: Re[2]: 80386 out of GENERIC Message-ID: <XFMail.20021216114502.jhb@FreeBSD.org> In-Reply-To: <9710634521.20021214232526@dds.nl>
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On 14-Dec-2002 Alex wrote: > > Dear/Beste phk, > > Saturday, December 14, 2002, 10:14:20 PM, you wrote: > >> In message <635948263.20021214220720@dds.nl>, Alex writes: >>> >>>Dear/Beste Johnson, >>> >>>I read this on the advocacy list. >>> >>>Tuesday, November 19, 2002, 7:56:44 PM, you wrote: >>> >>>> Support for the 80386 processor has been removed from the GENERIC kernel. The >>>> default FreeBSD kernel is now more optimized for modern CPUs. No longer do >>>> you have to settle for performance draining compatibility with hardware you >>>> haven't owned in a decade. >>> >>>I don't feel this is a good decision. (I still have a 486, act as a >>>small server and a 286 witch is in storage) This basally means that >>>any one who doesn't have the latest processor can't install FreeBSD. > >> No it doesn't mean that. > >> FreeBSD still runs on all 386 family CPUs, the only difference is that >> if you want to run it on a 80386 you need to enable an option in >> your kernel config file. > >> It will out of the box run on 486 and anything later. > > It means that you can not install FreeBSD on a 386 unless you have a > 486+ machine that can compile a new FreeBSD system and have a way to > get that version to the 386. > > My assumption was for such case. Lets say a home user with a pentium > II with Windows 98 and his old 386 as a FreeBSD server. 5.0 will be too slow to be useful on an 80386. Better off running 4.x or 2.2.x on a real 80386. Seriously. Also, if/when KSE fully matures the new thread library will need to use special instructions that are only present on the 486 and above (the same instructions (cmpxchg) that are the reason GENERIC doesn't include 80386 by default anymore). Emulating those instructions on a 80386 is expensive and requires kernel privilege, thus someone would have to add support to the kernel to trap the illegal instruction fault on a 80386 and then emulate the instruction. Thus, it's going to be _really_ slow on a 80386. FreeBSD 2.2.x and 4.x are stable and tested OS platforms and I think that for an 80386 they are a much better platform than 5.x or other future versions of FreeBSD will ever be. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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