Upgrade to 64 bit

[Gonesolo]

I have Kubuntu 6.06 LTS (i386) running on my PC at home. I have an AMD 64 and would prefere to run a 64 bit OS but I've had problems with other distros and my video drivers with Cedega. Now I have a nice setup with Wine/Cedega and my ATi driver all happily co-existing. But I still long for that 64 bit kernel.

So the question is .... Is there any way to "upgrade" my current 32 bit kubuntu to 64 bit or do I have to reinstall. If I change my Apt source list to x86_64 and run apt-get upgrade will that do it or is there more to it?

[askrieger]

Re: Upgrade to 64 bit

I'm afraid that there is quite a bit more to it. Simply changing your sources.list file to AMD64 would simply wind up breaking all your packages (even if you succeeded in doing that). If you really want AMD64, you must download an AMD64 installer disk and then, either install it as a second distribution along with the i386 version, or install it over the i386 version.

The real question is why you would want to do it. I use the AMD64 version of Kubuntu because it compiles Fortran95 and C programs faster than a K7 version of the i386 would, and then runs long, boring calculations somewhat faster (20 to 25 percent) than they would run in 32bit mode. "Normal" software is only about 10% faster than the corresponding K7 code.

On the other hand, I surf the web with my P4 laptop running an i686 kernel because I got tired of seeing popups saying that sites wouldn't open because I didn't have Flash installed (Flash is not available for AMD64.) I'm not a gamer, so I can't say whether you would gain speed on K8 compiled AMD64 code or lose the ability to run your favorite games at all.

[Gonesolo]

Re: Upgrade to 64 bit

OK thanks for the info. So as a follow up If I stick to 32bit what is the best kernel to be using. Should I stick with the stock I386 kernel or should I use a K7 kernel for an AMD or would the i686 be a better kernel to use.

And a bit of a newbie question. Whats the difference between these kernels and should they work ok on my current setup.

[askrieger]

Re: Upgrade to 64 bit

The different kernels have been compiled to use machine instructions specific to particular processors. For example if your processor is an authenticAMD and you want 64 bits, you would use the AMD64-k8 kernel because it has been compiled with specific instructions not found in Intel EMT-64 processors. For one of those, you would would use the AMD64-generic kernel (or, at least, I think you would). Similarly, for a Pentium-II,or above, you should use a 686 kernel. If you're using a modern AMD processor, you should be able to use the 686-k7 kernel (I've never tried it though). At the very least, I would think that you should be able to use the stock 686 kernel.

[heinkel_111]

Re: Upgrade to 64 bit

Following up on your kernel descriptions, which is the better for AMD64 X2 processors? (AM2 motherboard) Is there something to gain by cooking it up ourselves as opposed to using the generic one?
If I changed my 64 bit kernel to another version, but still 64 bit would it break packages? (In practical terms, will I need to reinstall?)

myuser@mycomputer:~$ uname -r
2.6.15-26-amd64-generic

^This is what I have now^

I am not ever going back to 32 bit for those pesky proporitery blingblings....they will have to follow where we lead, but does 32-bit flash, etc, work on WinXP 64 bit or are there special versions for WinXP64?

[askrieger]

Re: Upgrade to 64 bit

He -111: You should be running the AMD64-SMP kernel. I don't believe that will break your installation, if installed with the regular AMD64 software. I believe (i.e. I may be mistaken) that the user-mode stuff is all compiled to run on any AMD64 processor. You might gain time by recompiling for multiprocessor mode, so the question is would it buy you enough time to make it worthwhile to spend the time recompiling. But, it may be that the SMP kernel already does all the multithreading that you might be able to use conveniently. If you really want an expert opinion, I'd ask a kernel hacker.