[CentOS] 486 custom kernel

Tue Dec 8 21:07:36 UTC 2009
Robert Heller <heller at deepsoft.com>

At Tue, 08 Dec 2009 14:02:28 -0500 CentOS mailing list <centos at centos.org> wrote:

> Hi all,
> Is it possible to take the 686 CentOS 5, install that in virtual machine,
> install a custom kernel that is the 486 flavor, take that image and
> put it on a 8G CF card  - insert that into a small form factor 486 class
> machine and have that work?

Will this small form factor 486 class machine be on the public internet
network?  If not (and thus not needing any current security patches,
etc.), you might consider install RH 7.3 on it.  RH 7.3 includes a
*stock* i386 2.4 kernel (RedHat never built i486 kernels and I am not
sure if anyone else bothered to either).  I would also guess that the
small form factor 486 class machine probably is NOT going to have
modern I/O items, so you *probably* won't need any new kernel modules
(eg SATA or fancy video or sound or network cards, etc.). I fould a set
of  RH 7.3 CDs on-line (*one* of the old mirrors still has it on line: 


And I snarfed the ISOs to my server:


(I have an interst in using RH 7.3 on old '486 boxes and use them as
model RR control nodes.)

> I am hoping the extra instructions in a 686 (MMX, SEE etc) are not used 
> by any libraries

Only some libraries (glibc for one, but it is available in several
'flavors', I think including a vanila i386 flavor).

> that I would be using (just standard stuff) and the new 486 compiled 
> kernel would not be
> using those instructions either.
> Can this possible work? I am hoping to not use debian i386 basically.

Since various packages that would be installed on a 686 machine would
be built for the 686 arch, you can't just copy the image of the 686
install onto a 486 system.  You'll need to do a re-install to a 486
target.  You can rebuild the kernel on the 686 (virtual or otherwise)
and I believe all of the *.i686.rpm's are available as *.i386.rpm's. 
Somehow you will need to hack things at the install level to force a
plain i386 install.  You might need to hack anaconda and insert the i386
kernel or some such.  Or do a careful downgrade of all of the i686
packages to i386 packages (in addition to the kernel itself).

> Thanks,
> Jerry
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Robert Heller             -- 978-544-6933
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