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OneOfMany
Tux's lil' helper
Joined: 19 Nov 2003
Posts: 108
Location: Portland, OR USA
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 Posted: Wed Sep 12, 2007 8:45 pm Post subject: 64 bit + 32 bit x86 on one boot CD? [SOLVED] |
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Sorry if this has been hashed out before, but my searches turned up nothing. I know to install the 64 bit version of gentoo on my AMD/Intel processor I have to use the 64 bit boot CD. But I also know many things don't work quite as easily (sometimes need to use the 32 bit versions of things for win32codecs and other niceties). So I actually have 2 boxes setup and at various times feel the compulsion to reinstall from scratch to make sure I don't leave behind cruft (yes I come from a Windows world and use that more often, but I'm trying to get my Linux up to stuff).
To perform these 2 installs I need 2 CD's now. I'd prefer to be able to use 1 CD and just type in a different name when it asks for which kernel I want. Is this possible? Could Catalyst create a dual boot CD that would allow installation of either version on x86? Or is there an easy way for me to do this myself with the two ISO's?
One issue I foresee is the different support applications. Could they be shared? Or do they actually need to be completely recompiled for the other number of bits to work properly? I vaguely remember hearing about multilib before. Did that have to do with using 32 bit compiled programs on the 64 bit system? I think it is disabled by default now, but maybe that could help?
Thanks for any thoughts on this...
Last edited by OneOfMany on Sun Sep 16, 2007 5:53 am; edited 1 time in total |
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i92guboj
Bodhisattva
Joined: 30 Nov 2004
Posts: 10315
Location: Córdoba (Spain)
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| Posted: Wed Sep 12, 2007 9:28 pm Post subject: Re: 64 bit + 32 bit x86 on one boot CD? |
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| OneOfMany wrote: | | Sorry if this has been hashed out before, but my searches turned up nothing. I know to install the 64 bit version of gentoo on my AMD/Intel processor I have to use the 64 bit boot CD. |
Yes.
| Quote: | | But I also know many things don't work quite as easily (sometimes need to use the 32 bit versions of things for win32codecs and other niceties). |
No. win32codecs works with a 32 bits mplayer, but you CAN run a 32 bit mplayer into a 64 bits Gentoo. Just like you can run 32 bits flash on 32 bits firefox on 64 bits Gentoo.
| Quote: | So I actually have 2 boxes setup and at various times feel the compulsion to reinstall from scratch to make sure I don't leave behind cruft (yes I come from a Windows world and use that more often, but I'm trying to get my Linux up to stuff).
To perform these 2 installs I need 2 CD's now. I'd prefer to be able to use 1 CD and just type in a different name when it asks for which kernel I want. Is this possible? Could Catalyst create a dual boot CD that would allow installation of either version on x86? Or is there an easy way for me to do this myself with the two ISO's? |
I don't know the cruft you are talking about.
Plus I can't see the problem in using 2 cds. You certainly will need to reboot anyway, when you want to change from a 32 bits kernel to a 64 bits one to make the 64 bits installation. Possible? Yes, of course, you can put as many kernels as you wish as long as your boot loader can handle them. The boot loader doesn't care if the kernel is 32 bits, 64 bits, Windows or any other thing. Of course, you would need to manually setup at least a small image with the minimun required programs and libs to run a 32 bits kernel, and a 64 bits one, separately.
Basically, you need a 32 bit kernel, a 64 bit kernel, a 32 bit userland image, and a 64 bit userland image. The images could be minimal, like in the minimal installation cd. And, a bootloader that can handle that on a cdrom.
Now, I want to comment one thing you said:
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Could Catalyst create a dual boot CD that would allow installation of either version on x86?
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I hope you did not really want to say "x86", because, of course, there is no way to run 64 bits on x86.
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One issue I foresee is the different support applications. Could they be shared? Or do they actually need to be completely recompiled for the other number of bits to work properly? I vaguely remember hearing about multilib before. Did that have to do with using 32 bit compiled programs on the 64 bit system? I think it is disabled by default now, but maybe that could help?
Thanks for any thoughts on this... |
On Gentoo, the "multilib" capability reffers to the possibility to run programs compiled for 32 bits under a 64 bit environment. If your kernel has IA32 emulation on, and you have a multilib toolchain (and all the required libs compiled for 32 bits), you can run 32 bit programs under amd64 without any problem, because amd64 is capable of doing natively (there's really no emulation involved -as far as I know-, although the precompiled libs in portage are named emul-*). It is enabled by default, so, don't worry.
So, you probably could use a single amd64 kernel to install a 32 bit system as well. But it is not THAT trivial. As I already said, in Gentoo, "multilib" means that you can RUN 32 bit programs on a 64 bit system, but that doesn't mean that you can compile them easily without a lot of manual work.
Unless you are really bored, I wonder why do you want to do such a thing. |
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OneOfMany
Tux's lil' helper
Joined: 19 Nov 2003
Posts: 108
Location: Portland, OR USA
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| Posted: Thu Sep 13, 2007 11:40 pm Post subject: |
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Hmm...So the only detail is that I need to compile a 32 bit version of some packages. But as you said above I can't do that easily. Of course there are the 32 bit bin packages, but that doesn't quite feel "Gentoo" enough (compiling stuff with my own flags and options). I'm looking into doing this because I have 2 computers at my desk anyway. So I figured it would be easy enough to have a 32 bit and 64 bit machine if I wanted to play around with porting/testing stuff on 64 bit, but didn't want to worry about stuff not working on my default machine (without extra work).
By cruft I'm meaning anything not cleaned up completely by any uninstalls, or some how incorrectly setup initially because I didn't have a certain option enabled, or maybe I didn't get to see the info at the end of the emerge (only recently learned about elog viewers). On many Windows boxes they eventually start doing odd things that you can't explain. Often a format and reinstall of the OS + apps can help.
I realize gentoo uses amd64 to refer to the 64 bit mode that some Intel and AMD processors can run in. I meant x86 vs Alpha vs whatever else is also 64 bit. As far as I know the commands are the same for most 32 bit and 64 bit instructions on the amd64 compatible chips, but with some extra 0's for the usually 32 bit op codes. That's why I was lumping them together...
And yeah, I can have 2 CD's...was just wondering if there was a relatively easy way to create a single one. Maybe with isoLinux or some other multi boot setup assuming I can't get catalyst to do what I wanted. I already use the minimal CD, so there is definitely enough space left for a couple versions of it. |
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i92guboj
Bodhisattva
Joined: 30 Nov 2004
Posts: 10315
Location: Córdoba (Spain)
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| Posted: Fri Sep 14, 2007 1:47 am Post subject: |
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| OneOfMany wrote: | | Hmm...So the only detail is that I need to compile a 32 bit version of some packages. But as you said above I can't do that easily. |
To compile your own 32 bit packages on a 64 bit system, you need either a 32 bit chroot or a crossdev setup. Just look around the these, there is quite a lot of info. A 32 bit chroot is basically a whole 32 bit gentoo install. That you chroot to, from an amd64 system. Since amd64 is able to do that, there is no problem (of course, chroot'ing from 32 to 64 will never work, as a 32 bit kernel working on x86 mode can never even run 64 bit binaries).
If you choose that method, you can emerge any package into that chroot, then quickpkg it, copy it to your 64 bit packages dir, and then emerge it using --usepkgonly. Again, I find this a waste of time, unless you have a good reason to do so. And *I wanna have more customization power* is not a good one. Of course, your time is yours, so you decide how to spend it. I do lots of useless thing everyday 
That's probably the easiest method.
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Of course there are the 32 bit bin packages, but that doesn't quite feel "Gentoo" enough (compiling stuff with my own flags and options). |
Compiling 1,2 or 20 packages with custom cflags is not going to help you in any way (it can only get worse, cause the default flags are optimal anyway). Anyway, if case you feel that is not optimal, I can tell you that having a whole 32 bits installation to chroot on in from another -independent- 64 bits installation, is even *more* suboptimal, again, unless you have a real reason why you need to compile the package yourself.
I suggest you also that you make a list of packages that you are going to compile on 32 bits to use them under 64 bits. Consider that some binary packages are binary not just for the sake of being binary, but because they are provided as binary packages upstream (for example, opera and flash). In these cases, you are going to get the same precompiled stuff in either amd64 or x86.
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By cruft I'm meaning anything not cleaned up completely by any uninstalls,
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Portage clean out every single file that belongs to a package when that package is uninstalled. Of course, it can't clean files that you created using that package, and that include config files and log files, not only docs. In linux there is no such concept of cruft. Libraries can be fully instaled or uninstalled, but even if they remain, they are not loaded via some obscure black magic on a silly registry key. Libraries are dinamically linked on demand. There is no performance degradation and your system will be sane as long as you use portage to install and uninstall stuff. Of course, if you compile and install by hand then you are on your own.
| Quote: | | or some how incorrectly setup initially because I didn't have a certain option enabled, or maybe I didn't get to see the info at the end of the emerge (only recently learned about elog viewers). |
If you read the info portage tells you (you are supposed to do so), and you use the handbook to install gentoo, you should have not big problems. For the punctual problems that can arise, here's the forum, and there's also the mailing lists.
I realize gentoo uses amd64 to refer to the 64 bit mode that some Intel and AMD processors can run in. I meant x86 vs Alpha vs whatever else is also 64 bit. As far as I know the commands are the same for most 32 bit and 64 bit instructions on the amd64 compatible chips, but with some extra 0's for the usually 32 bit op codes. That's why I was lumping them together...
| Quote: | | And yeah, I can have 2 CD's...was just wondering if there was a relatively easy way to create a single one. Maybe with isoLinux or some other multi boot setup assuming I can't get catalyst to do what I wanted. I already use the minimal CD, so there is definitely enough space left for a couple versions of it. |
I never bothered with mutiboot livecds, so I can't help there. I suppose googling could help, haven't looked myself. Certainly, it is possible to do so. There are quite a lot of cds that provide menus to boot in one or another way. Using 32 or 64 bit images is just a matter of loading one or another kernel. |
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OneOfMany
Tux's lil' helper
Joined: 19 Nov 2003
Posts: 108
Location: Portland, OR USA
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| Posted: Sun Sep 16, 2007 5:52 am Post subject: |
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| I don't know why I didn't think of this before! I can chroot into a 32 bit environment from a 64 just fine. So I should be able to use a 32 bit stage (from a 64bit CD) if I want to install a 32 bit system! I just need to remember that special chroot command (32in64 or something like that...been a long time since I used it). |
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i92guboj
Bodhisattva
Joined: 30 Nov 2004
Posts: 10315
Location: Córdoba (Spain)
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| Posted: Sun Sep 16, 2007 12:31 pm Post subject: |
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| OneOfMany wrote: | | I don't know why I didn't think of this before! I can chroot into a 32 bit environment from a 64 just fine. So I should be able to use a 32 bit stage (from a 64bit CD) if I want to install a 32 bit system! I just need to remember that special chroot command (32in64 or something like that...been a long time since I used it). |
That's correct, However, that will not work if you intend to use this livecd on 32 bit (non x86_64 capable) machines. |
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