Request help: x86 to AMD64 conversion

[acerbix]

Hi,

I have a 32 bit gentoo install ("emerge -Du world" performed at least weekly) on a laptop with an athlon 3200+ processor: I would like to convert the install to 64bit. However, I am unable to find any guide or help on how to do that. Is it at all possible to "upgrade" an existing install to 64 bit, or do I have to scratch and rebuild? Is there any thread/link/reference I can use?

Currently I have:

CHOST="i686-pc-linux-gnu"
CFLAGS="-O3 -march=athlon-xp ..."

Thanks in advance

[Gentee]

I suggest you back up everything in /home (you can probably re-use it) and everything in /etc (*not* to restore completely, but just so that various files like xorg.conf can be copied back instead of re-typed) and any other bits and pieces you can think of...and then build a shiny new 64-bit system from scratch.

If you build the underlying system with the same desktop environment, applications and so on, then you should find that you can simply attach it to your old /home and all your menus, preferences, panels, mixer settings etc. will work as before. Of course, some things won't work quite as they did before (you'll need to install 32-bit binaries, or even a whole 32-bit chroot, to run OpenOffice or play certain 32-bit multimedia formats, macromedia flash and so on) but, depending on your particular setup, it shouldn't take nearly as long to get your 64-bit system fully configured as it did your original x86 system...simply because so much tuning and tweaking is likely to have gone into /home, which can be moved straight across.

Good luck!

[acerbix]

Hi,

The gentoo-wiki does not talk too much about a favored AMD64 install process. After a brief search, I was able to dig up livecd based install mechanisms (i.e ahorn type livecds) or the official livecd based install by using the handbook. However, I could not find an official AMD64 stage 3 image, only an athlon-xp based image. So I guess I am a bit stuck trying to figure out which way I should go.

Any recommendation will be greatfully accepted. I did try to search the forum for guidance before posting this, however, the search did not turn up anything helpful.

Thanks

[Isaiah]

Easiest update from x86 to AMD64
Building a new AMD64 system
Glibc overlay with amd64 performance patches and more!
Good luck

[pgilbert]

Definitely start from scratch, but keep a few files around like xorg.conf. I just went through an attempt to convert and learned a lot, but had to start from scatch in the end. One problem is that all your binaries are 32 bit. Another is the the setup for the kernel config is not right, so you don't even seem to get the right questions in make menuconfig. You end up with a 32bit kernel and $HOSTTYPE=x86 rather than x86_64.

You might keep the 32 bit system on a separate partition if you have space.

If you have a fast Internet connection you can start with the instal-amd64-mininial CD and roughtly follow the Quick Install Reference but skip the stage tarball, unpack the portage tree straight from the net, pick mirrors, etc, then just do emerge --update --deep system in the chroot. Then emerge gentoo-sources and compile the kernel, grub, etc., all in chroot. This gets you to an up-to-date system immediately, rather than installing old stages from a CD and then updating.

I didn't try this, but you might copy your old /var/lib/portage/world to the new system and then do emerge --update --deep world, so you get right back to your old world setup. Has anyone tried this?

[acerbix]

Isaiah, thanks so much for the pointers... I am currently building the cross compiled kernel. Once that is done, I am guessing I need to boot into the new kernel, and then using the cross compiler, rebuild the toolchain and compiler, then using the rebuilt compiler rehost the compier. This is what I am thinking of doing:

USE Flags:

[pgilbert]

Make sure you change the architecture and default settings for portage, determined by the sym link
/etc/make.profile -> /usr/portage/profiles/default-linux/arch/make.defaults/200x.x
and check emerge --info [--verbose].
Good luck, and let us know how it goes. You are about at the point I decided it was easier to start from scratch.

[Isaiah]