Installed Wrong Stage3 Tarball (i486, not i686)

cniall · n00b Joined: 20 Dec 2009 Posts: 43

When installing my new Gentoo system, it turns out that I accidentally downloaded the wrong Stage3 tarball for my system: a i486 version instead of the i686 that I would assume my Intel i5 would take.

How would I recover from this? Could I just download the correct Stage3 tarball and not have to reinstall my system? In my /etc/make.conf file, it also has the CFLAGS, CXXFLAGS and CHOST variables insisting that it is an i486 system. What do I do to recover from this (dumb) mistake?
CFLAGS="-O2 -march=i486 -pipe"
CXXFLAGS="-O2 -march=i486 -pipe"
CHOST="i486-pc-linux-gnu"

I'd guess that I'd download the correct tarball, install it as in the installation guide (but from a system that is already installed) then recompile everything (how would I do this -- recompile the kernel and reinstall that, then 'emerge --update --deep --newuse world' in the shell?), but I really don't want to do anything in case I break the system further.

If it helps, everything seems to be working fine, just for the wrong architecture -- i.e. programs load and work as they should, as far as I can see, but they're compiled for i486.

(Sorry if this is already answered somewhere, but a search didn't reveal much)

Sade · Posted: Sun Dec 20, 2009 3:44 pm Post subject:

You need to follow one of two paths, which you've already correctly guessed.

1) start from scratch using the correct tarball
2) recompile everything (Gentoo Change CHOST HOWTO)

Changing CHOST is not really advised for novice Gentoo users, besides that you also need to change your profile.

We are glad to help you along the way, but first you need to decide, do you want to learn something (path 2) or do you want the quick fix (path 1).
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cniall · n00b Joined: 20 Dec 2009 Posts: 43

I'll have a go with the second option; if that fails, I guess I can always format and just reinstall since it's not as if I have any valuable files on the disk. Thanks; I follow the howto and post again if I get stuck or something.

NeddySeagoon · Posted: Sun Dec 20, 2009 5:04 pm Post subject:

cniall,

Its not worth bothering with the CHOST change, nor the i486 to i686 update.

What you have now is an install capable of running on a 486 CPU. If you change your CFLAGS and CXXFLAGS, your tool chain will emit code for whatever -march you set. The toolchain itself will stay i486.

If you don't nothing else except the above, as updates are applied to your system, packages will be updated to use the new CFLAGS and CXXFLAGS.

Changing CHOST and rebuilding the toolchain will make little or no difference to its performace as these programmes make little or no use of the additional instructions, unlike media programmes that will take advantage of mmx, sse and so on. You also need USE flags set for that.

The CHOST changing guide was originally produced when glibc stopped supporting i386 CPUs around version 2.3, which meant that users with i686 CPUs and an i386 CHOST (from being careless with a stage 1 install) had no glibc upgrade path.
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zyko · Posted: Sun Dec 20, 2009 8:43 pm Post subject:

cniall · n00b Joined: 20 Dec 2009 Posts: 43

zyko · Posted: Mon Dec 21, 2009 12:14 pm Post subject:

Where were your issues in Ubuntu?

From an end-user perspective, Gentoo's amd64 installation isn't supposed to behave any different from an x86 installation. There are some internal differences, like a multilib setup that allows you to run ia32 code, but that's all "under the hood".

cniall · n00b Joined: 20 Dec 2009 Posts: 43

Mainly that it was an absolute pain to find certain packages, but thinking about it since Gentoo compiles from source that would probably be far less of an issue. I might jump through the hoops of a CHOST update to change it to 64-bit; I'll have a look around. (Hopefully I won't break anything in the process!)

Jaglover · Posted: Mon Dec 21, 2009 4:53 pm Post subject:

cniall,

switching to 64bit means fresh install.
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cniall · n00b Joined: 20 Dec 2009 Posts: 43

If (more aptly, when) I break the system beyond my ability to repair without reinstalling Gentoo, then, I'll have a go at 64-bit: until then, I'll just stick with 32-bit.

NeddySeagoon · Posted: Mon Dec 21, 2009 7:02 pm Post subject:

cniall,

You can dual boot 32 bit and 64 bit. Make a new partition on yur drive for a 64 bit install and take it for a spin.
Theres no pressure as your 32 bit install is there for everyday use.
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NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

cniall · n00b Joined: 20 Dec 2009 Posts: 43

I never thought of that -- I'll probably do that fairly soon. (For some reason the idea of dual-booting two variations on a Linux distro never occurred to me since I've only ever dual-booted between Linux, which I've used for everyday purposes, and Windows, which I use almost exclusively for gaming).