Confused About Gentoo
 

I'm just abit confused about something inregards to Gentoo.
I have been doing a bit of research into the Gentoo Installation & how it works etc.
AnyWay I have 2 PCs ,1 is a P4 & the other is a AMD64.
Now it says in HandBook that you can use the Install CD to create & optimise Gentoo to either be created for which ever kind of Computer you have wether its "sparc or AMD64 or i686 etc etc, - But then I noticed that you can download a AMD64 bit version to install for Gentoo as well.
This confuses me abit ? Are we supposed to download the 64bit version if we want to install on a 64bit PC or can you just download the Normal CD version & optimise it for 64bit version ?
Or am I misunderstanding the concept.
As I have the latest Universal CD which I downloaded thinking I could use it & optimise install for which ever PC I install it on .
I know you can install 32bit Distros on a AMD64 but I thought with the Universal CD that I can create either a 32bit or 64bit from it with out having to download another version (like theres a 64bit version install CD of Gentoo as well ) which confuses me .
Could someone be able to give some insight into this.
Thanks AnyOne.

Re: Confused About Gentoo
 

Gentoo has CDs for several arch's. You would still download the cd for your architecture. The optimization comes during the install. Gentoo has no official installer, and must be installed via the command line, one command at a time. An install can take a couple of days. There is a beta gui installer on one of the cds, but I have read it is quite buggy.

Anyway, Gentoo is a source distro, and everything installed must be compiled. On the cds are pre-compiled binaries for your architecture, but they are not truly optimized for your hardware. The optimizations in Gentoo come from the fact you literally choose the compiler options for your specific processor during install. All programs installed after the base system install are compiled using these optimizations. You can install an entire Gentoo system without compiling anything (called a GRP install), but then you miss the whole point of Gentoo.

Not trying to put you off, just want you to know the install takes a long time. The docs are EXCELLENT, and you must read them step by step. I have no experience with 64 bit platforms, so can't say how well they work.

Thanks very much ,but just to clear it up abit ( now I might have these the wrong way round) but if I was installing from the normal universal CD not AMD version and chose " CHOST="i686" & then march=K8 etc ( or could I choose "K8" on both ) would I not have a 64bit distro doing this ? or are the Flags etc on this CD be only to optimise for 32bit , which is why I am confused..
AnyWay the point is why are we given the choice it seems to choose different kinds of PCs using " CHOST="K8" or "march=Athlon-xp" etc then.
Inother words if I use this normal universal CD to install with , should i USE " CHOST ="K8" as the PC I want to install on is a "K8" AMD64 or would I be best to use "i686" .
I just hope I havn't now confused your self as well with my Question?.
The point I am trying to make is I have the normal Universal CD not the AMD version & am wondering what I would choose if I used this CD or would I have to use the 64bit version for Gentoo to work on That PC as I was preety sure I could use both versions?
AnyWay

I think that this question is best directed to the Gentoo forums on their site, given its highly technical and specific nature.

Yea ,Fair enough,
Thats why I asked if I might of confused you as It was just as tuff to explain.
AnyWay Maybe a Gentoo Pro might give it a go?
Also I might copy what I wrote & then edit it & post it at Gentoo Forum like you said.
Thanks AnyWay

The CDs are optimized for a specific architecture, that's why there are Cds for s specific architecture. You can't take a 32 bit CD and optimize it for 64 bit because the code is different. The point is, the binaries on the CD are optimized for a specific processor, but not for your specific hardware. During the install, everything gets compiled on and for your hardware.

All right, then ... as Sargek said, the essential difference of Gentoo, among the other distros, is that you compile it from source, on your own computer. There are almost no "binary" packages, except for some (like OpenOffice) that are notoriously difficult to compile, where you have the choice to :cry: compile it or :cool: use the binary.

If you select the right compiler-options, and select your processor-type appropriately, then your compiler may generate 64-bit code for a particular application. Even in a 64-bit world, not all of everything is 64-bit. (In fact, right now, most things are not 64-bit.)

Now, I said that "you compile it from source," but most people using Gentoo do not start out that way. They ordinarily do not choose to do what theoretically can be done, which is to compile everything from source-code, beginning with a "toolchain" and working all the way up. What they usually do is to start with an Installation CD which contains pre-compiled binaries for the foundation system. But, in order to get the desired effect, they must start with the CD that is most closely matched to their hardware, especially if that hardware is "exotic." If they don't, it will run, but it won't run as fast.

The so-called "Universal" CD is a somewhat-generic installation CD for "a 32-bit uninteresting x86 processor." If you are starting with a 64-bit system, however, I would recommend starting with the CD for your particular processor-type. The binaries on this CD will have been built with the most-optimal options for your processor. And you want to use this, because as much as possible you'd prefer not to be working in a 32-bit world... you bought a 64-bit processor; you want to use it.

[The Gentoo AMD-64 FAQ at the Gentoo site is mandatory reading ... including the several articles and threads that are linked from there.]

Some people assume that a 64-bit processor will be "faster than" or even "twice as fast as" a 32-bit one, and this is not the case. I'm afraid that there are already some 32-bit motherboards that have had 64-bit hardware essentially strapped-on, where the various components are not properly speed-matched and the bus-width forces a Ferrari onto a two-lane highway. The actual speed difference depends upon: (1) the application; and (2) the compiler-flags used. It also depends on (3) how long the processor can remain in 64-bit mode at any one time; mode-switches are expensive.

For installing Gentoo it isn't required to download a CD from the Gentoo site. Installing Gentoo can be done from any linux-environment. That means your current distro, or, if you don't have one yet, Knoppix.
(I can recommend installing from an GUI-environment because then it's easier to read the Handbook online, and install your system at the same time.

Second step is downloading the stage3-tarball, kernel and portage. You can choose which version (amd or intel, 32 or 64 bit) to download from the mirror site... So no need to worry I think.

In short: The Install-CD and the distro you're gonna install are independent from eachother

OKEY ,Excellent.

You can install and read the docs at the same from the livecd by logging into another virtual terminal and switching back and forth. I guess either way works, but it depends on how comfortable you are with the command line.

Excellent explaination, thanks for adding on to my meager ramblings...;)

I hope I am right here, as this is how I meant to explain what I was trying to say in beginning but didn't quite know what I was explaining without proper knowledge .
Using the Normal Universal CD I have instead of 64bit, if I chose "K8" as my processor & " i686 " as the CHost and " -O0 " as my Optimization then that would be what I am supposed to do or Should I do " i686 " for both .
In other words if I am using 64bit CD then I know that I would tell it my Processor is " K8 " but using the 32bit CD would I do the same thing .
AnyWay thats how I would of explained it the first time if I knew what I was talking about. As I have read a fair bit from the HandBook but it doesnt seem to explain what you would choose if installing from the 32bit CD on a AMD64.
I do hope to Download the 64bit version one day as advised but for now I am settling on using the one I have.
I just want to add I understand preety much what everyone has explained & is appreciated but I just thought that with abit better understanding of Gentoo that I would rephrase what I was trying to Ask.
Cheers
Thanks Everyone

No...choose the 64 bit cd for the 64 bit processor. You cannot compile 32 bit code to be 64 bit code for a 64 bit platform, the code is different. Understand?

Yes I understand,
I just thought it was important for Gentoo to still know what my Proccessor was for it to install and setup properly. that was what I was trying to explain.
I appreciate your help.
thanks Browser

You are welcome - it is important to tell Gentoo this, but if you are trying to optimize 32 bit code for a 64 bit proc, the point is kind of moot. I think it will run, but I'm sure you won't get any advantage until you install the 64 bit cd. Never dealt with anything 64 bit, so I am speaking hypothetically, but I know Gentoo creates cds for specific architectures for a reason.