amd64 or i386?
 

Yesterday I killed KDE Installation beyond repair. I was removing a lib with (obviously) so many dependencies, that the entire desktop enviroment was removed... or at least a good part of it. After recognizing that there isn't much I can to, to recover KDE I thougth: Hey, why not trying gnome instead? I installed gnome, played around and decided that a lightweight WM is everything is need and installed Fluxbox. Problem is now, that my root partition is crowded with a bunch of KDE and gnome apps and some libs, which makes the system as big as 4.4GB, which is far to much. My idea was to reinstall debian, to get a new and shiny minimal install for maximal performance.
As I have got an Intel Core Duo cpu with 2x 2.33GHz, my question is, if the amd64 distro is recommenden? I figured out, that there are a bunch of programms not working with 64bit Systems like Opera an Wine which I use pretty much. Is the performance gain by using amd64 high enough to justify messing around with the 32bit emulation for certain packages? In most cases I don't really use much of the cpu, i.e. I'm not doing huge computations of data like movie editing, so a i386 system would theoretically be enough for the moment... has anyone clues about that?

thanks in advance :)

I recently installed Lenny on AMD64. The system is quite fast, although I don't need the speed either, I appreciate the responsiveness. Opera works flawlessly, including Flash. But I could not get Java to work although it is available in 64-bit Lenny

As far as I can remember Acrobat Reader is not available.

jlinkels

Completely unnecessary. The x86_64 architecture is multilib. With a standards compliant distro, 64-bit and 32-bit applications will run side-by-side. I'm typing this in a 32-bit Firefox while I have a 64-bit Gnumeric, Evolution, and Nautilus open too. Oh, and there's a 32-bit Acrobat Reader executing too. If you use a standards compliant distro, you will be able to use Opera and Wine simply by installing them and double-clicking the icon. Nothing fancy.

You're right though that if you're not doing computationally intensive tasks, you won't really notice a difference. But don't be scared of those extra 32 bits. There are plenty of packages available for the 64-bit ABI too. Not as many as for the 32-bit, but that's OK because you can use either.

I've been using a multilib distro for almost two years. It's rock solid and I haven't lost any functionality that I had with 32-bits.

Forget it, stupid question :\

Weibullguy, that is interesting. I see your distro is (C)LFS, apparently that one is multilib. Is that true as well for Debian (Lenny) as it is available in the standard repositories? Do you have to compile libraries yourself, put the 32 bit libraries on the system as well, do you need LFS, other special distros?

I admit this is a lack in my knowledge. I know about (dynamic) libraries, and that libraries must be compatible with the kernel and the architecture, but I an not able to grab the concept of multiple libararies. How does a program know whether it is 32 or 64 bit and which libraries to load. I would be happy if you can provide some pointers to further reading.

jlinkels

I used Debian many moons ago (like back when woody was considered unstable) which was before I was an x86_64 user so I'm not current on how Debian implements anything or which *.iso to use. From what I've read here and elsewhere leads me to believe Debian initially wasn't standards compliant wrt the x86_64 architecture. Primarily I believe that because a 32-bit chroot was required to execute 32-bit apps on 64-bit Debian. Recent versions like Lenny may be compliant such that a chroot isn't required.

A quick test is to look at the file system. If there are ONLY lib or ONLY lib64 directories, then you're not standards compliant. If there are BOTH lib and lib64 directories, then you might be standards compliant. Both of my kids use 64-bit Ubuntu on x86_64 machines and Ubuntu puts things in non-standard locations. I don't know if that's a holdover from the mother distro or Ubuntuisms. It doesn't cause a problem when they install software using apt-get because the folks who maintain the *.deb packages should have dealt with these idiosyncrasies. It can become a problem when they try to install software from source or third-parties.

Yes, CLFS is multilib on the x86_64 architecture (and MIPS, Sparc, PowerPC). They have "pure 64-bit" instructions for the x86_64 architecture, but technically that results in a broken OS. It'll work, but there are issues that aren't present in a multilib build in my experience.

Conceptually, it's really not that difficult. 32-bit libraries live in */lib and 64-bit libraries live in */lib64. You don't need a 32- and 64-bit version of everything. All but six applications on my CLFS machines are 64-bit. I run a 32-bit Firefox (for plugin compatibility), mplayer, Acrobat Reader, Wine, Nero, and Lacie's lightscribe. Notice the common theme? I only need 32-bit support for third party and non-Linux software. Of course, any libraries that those 32-bit applications need also must be 32-bit.

Reading materials? Well most of it is really pretty dry since it's all technical documentation and standards. Take a look at the CLFS instructions for multilib x86_64. It'll give you a basic idea of one way to implement multilib support (IMHO, it's a very clean and simple approach).

After that, you could also head over to http://refspecs.freestandards.org/ and read the documents there. I warned you it's dry reading! Start with the AMD document x86_64-overview.pdf to understand some of the hardware differences other than 32 extra bits. Then dig into the specs themselves. Just bear in mind that the x86_64 specs build on the x86 specs, so there's a lot to read.

This is a whole new world. Now that I knew what to Google for, there is a wealth of articles about multi-lib Debian and the packages available for that. A number articles are outdated and show the different stages of development. The current status seems to be that many 32 bit libs seem to be available in the ia32 package. When I have the next time slot available for Linux play-around, I'll check and try.

Thanks for the eye-opener

jlinkels

In this case I was misunderstanding your post. I thought you were talking about a specific multilib version of the debian distro. Perhaps i didn't made clear enough, that I want to continue using debian, as I know I can work with it and don't have the time to get into LFS (tho it might not be as scary as it sounds :) ).
I have my final exams ahead and first of all need a system that works. I think I'll stick to my existing installation so far, as the only problem I have is, that my root partition becomes crowded. If I feel I have enough time, I'll check the amd64 version and see if I can get everything working as far as I need it. If not, I can still fall back to the i386 version.
Still, is there anyone truely missing an app or functionality in amd64 he found in i386? As you may understand (or not) time is important factor for me right now, and I hope I can safe some wasted days by asking these questions :).

I understood that you wanted to use Debian. Sorry, I was unclear. I was saying I can't answer questions specific to Debian because I haven't looked under Debian's proverbial hood in years. In the beginning I don't think Debian's AMD64 release was standards compliant, but newer ones like Lenny may be. Without any research on my part (meaning I may be completely wrong) it looks like the DVD images in this directory are the ones for the x86_64 architecture --> http://cdimage.debian.org/cdimage/we...amd64/iso-dvd/

The last four paragraphs were really in response to jlinkels.