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Dropping 386 support


The kernel team is considering dropping 386 support (the 80386
processor, not the i386 arch) from Debian.  Currently, in order to
support 386, we include a 486 emulation patch (the patch can be viewed
from here:
<http://svn.debian.org/viewcvs/kernel/trunk/kernel/source/kernel-source-2.6.8-2.6.8/debian/patches/x86-i486_emu.dpatch>).  The patch is a requirement for 386 machines, as debian's gcc generates binaries with 486 opcodes.  This patch is known to be buggy (see bug #250468), and is considered unreleasable.  The members of the kernel team don't have the hardware, time, and/or desire to fix it, and the upstream author is too busy to fix it.  As d-i rc2 is about to be released (and that is presumably what sarge will release with), we need to make the decision what to do.  We have two options; we can either keep the patch in, risk releasing sarge w/ 386 support containing known security holes, and hope someone someone fixes the problem soon; or, we can drop 386 support completely.

Reasons for dropping 386 support are as follows:
  * d-i currently requires at least 20 megs of ram to install.  My 386
had 4 megs of ram, which required using lowmem w/ potato's installer.  I
don't see standard d-i as being a viable option for installing debian on
your 386 anytime soon.
  * Potato ran decently on my 386 (functioning as a NAT box).  I
upgraded to woody, and it ran much slower.  Sarge will be even worse;
this will not get better, especially considering 486 opcodes will be
emulated on the 386.
  * Memory requirements have expanded, as have disk requirements.  i386
kernels require an initrd, and use more memory than, say, 2.0 or 2.2
  * Embedded 386 users will end up creating custom kernels, anyways;
they will want to strip out unneeded functionality to pare down the
memory requirements of the kernel.  They can, of course, also apply the
486 emulation patch to their kernel.

Reasons for keeping 386 support:
  * 386 users currently running woody will be left out in the cold, wrt
security updates.  Of course, there's nothing stopping them from
coordinating with the security team to offer security updates for woody
long after sarge releases; I wouldn't bet on it, though.

Given d-i's memory requirements, and the fact that you'd be hard-pressed
to find a (desktop) 386 system with more than 16 megs of memory, I don't
consider debian 3.1 to be a viable candidate for installing onto a 386.
Also, note that if we do drop 386 support, I will rename
kernel-image-2.6.8-386 to kernel-image-2.6.8-486, and update
optimizations accordingly.

Comments?  Thoughts?

Andres Salomon <dilinger@voxel.net>

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