switching from 32-bit to 64-bit

[gaf-mNDKBlG2WHs at public.gmane.org (Jerry Feldman)]

On 07/29/2010 11:27 AM, Dan Ritter wrote:
> On Thu, Jul 29, 2010 at 10:12:01AM -0400, Seth Gordon wrote:
>  =20
>> I have a desktop machine at home that used to run 64-bit Ubuntu.  Then=
=20
>> the hard drive went south, so I got a fresh drive, bought an Ubuntu=20
>> CD-ROM from the Micro Center, did a fresh install from the CD-ROM, and=
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>> then upgraded over the network to the then-latest version.
>>
>> At some point I noticed that I was running the 32-bit version of the O=
S,=20
>> not 64-bit.  Is there a relatively painless way to move everything ove=
r?=20
>>   (I need to upgrade it from 9.10 to 10.04, in any event.)
>>    =20
> Nope. Unlike switching kernels, x86-32 to x86-64 is a complete
> architecture change.=20
>
> There is no in-place upgrade. Your best bet is to add a disk,
> install 64-bit on that, test things, and move data over.
>
>  =20
You can theoretically do this, but it is a very big job and very easy to
screw things up.
(1) filesystem (not 100% sure here).
(2) kernel
(3) kernel modules - modules are coordinated with the kernel.
(4) libraries. /lib, /lib32, /usr/lib,/usr/lib32, /lib64 /usr/lib64
(64-bit libs are symlinked to lib).
(5) commands although most 32-bit commands will work in a 64-bit
environment.
(6) stuff I forgot :-)

If you create another partition with your home directory, possibly
/usr/local, and possibly some of your downloaded applications you are
preserving most of the stuff you added, then you can do a clean install
by reformatting the boot and root partitions.

Ubuntu like Fedora, and SuSE provide free downloads of the iso files,
and Ubuntu only provides CDs. It would have taken you less time to
download and burn a 64-bit Ubuntu CD than the time to go to Microcenter
although I do like to support them.




--=20
Jerry Feldman <gaf-mNDKBlG2WHs at public.gmane.org>
Boston Linux and Unix
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