hi,
i'm very new to linux. i've just install a redhat linux 9.0 system on my computer. i have go through few threads here and got some idea about what is i386 and i686. but can i know:

how do check my system so i can know whether it is compiled in i386 or i686? (use any command? or can check it in any file?)

and few more question list below:

1.) i have download .iso copy of redhat linux 9 from website. the file name is shrike-i386-disc1.iso and so on.(3 disc total). if i burn this to CDs and use it to install redhat linux, does it mean my installation is a i386 version? or it can detect my cpu model (i'm using pentium III) and intall a i686 version along the installation process?

2.) there're a lots of add-on program (like mplayer,...) on the sites thats package in i386 and i686 (rpm packages) for download. if my kernel is i386, and i install a i686 program, will it run smoothly? how about a i686 program install on a i386 kernel?

3.) if my kernel is i386 and i want to upgrade to i686, am i just need to recompile the kernel and install it. or i have to reinstall every things on my computer? (for compatablity or what' sever reasons)

hope anybody can help me.
thanks a lot for you.

Any piece of software can be compiled for any processor. The i386 and i686 are two examples of different processors; you can find out what you actually have by looking in /proc/cpu

1) Red Hat will autodetect your processor and install an appropriate kernel image, although it may be better to install the kernel-source, configure it and recompile your kernel anyway if you're interested in speed. (You'll find instructions for how to do this on tldp.org, this site, or the Red Hat documentation).


If you have an i686 (or above) processor, then you can happily run all i386 or i686 programs, and interchange them quite happily (the dependency of an i686 or i386 package is on your hardware processor, not on the kernel or any other installed software; the answers to 2) are yes and yes). Some software, notably including the kernel (but also some applications including mplayer) will have a significant speed-up when compiled for a i686 against an i386.

3) You can recompile everything to upgrade, but there's probably little point in doing so. I'd just recompile the kernel, and any software that was running too slowly.

For a PIII, go with i386. An i686 (I believe) is a P4 and up. However, you cannot run an i686 program on an i386 computer.

I have a total noob question here. When you talk about recompiling a kernel what do you mean by this and how do you do that?

Thanks

Search, and ye shall find.

did you buy it in 1989?

blazted, if you don't know what it means, you don't need to know what it means. basically just like recompiling individual programs, you can recompile the very core of Linux if you want or need to. there are guides around you can search for if you want to do this.

Ya i am using red hat and its umm /proc/cpuinfo pretty sure a lot of things varry from distro to distro if i am correct.

first of all,
thanks for all response , especially rjlee, you're very helpful.

now i've find out something by using the command "uname"
here's few lines of codes:

[hanbin@localhost hanbin]$ uname --kernel-name
Linux
[hanbin@localhost hanbin]$ uname --kernel-release
2.4.20-8
[hanbin@localhost hanbin]$ uname --kernel-version
#1 Thu Mar 13 17:54:28 EST 2003
[hanbin@localhost hanbin]$ uname --machine
i686
[hanbin@localhost hanbin]$ uname --processor
i686
[hanbin@localhost hanbin]$ uname --hardware-platform
i386

so now i'm sure that my pentium III processor is i686.
i just want to clarified:
is that "hardware-plaform" refer to my kernel?

one more question:
if my kernel is i386, is that mean every program i compiled will also in i386?
thanks for every one who are willings to help.

from what my fried told me, i386 is for everything. as for i686, i have i686 and i am using a newer celeron processor. i am new to linux and i do not know what processors fit into which categories

If your kernel is compiled for a 386, this does not effect any other programs.
However, whenever a program accesses a hardware device, like a disk, it goes through the kernel. So an i686 kernel will result in faster programs than using an i586 kernel, which is faster than an i486, which is faster than an i386. Recompiling just the kernel for the right processor will tend to make all the programs the right speed.

can somebody answer this question?

I'll repeat this that I typed for other posts. The Intel architecture model 80x86 designates each processor core. The X is a number from 0 to infinite but for now it is from 0 to 7. Each model adds few more instructions and sometimes a new feature although each model does not have to increase transistor count. If you have an 80686 processor, you can run software that was compiled for 80686 and lower. If you have an 80386, you can only run software compiled as 80386 and lower. Each increasing model should be better but it seems that Intel likes the yo-yo effect when they introduce new processors.

Pentium III is not an 80386 its an 80686. A Pentium 4 is an 80768 but it is not any better than some 80686 processors. AMD Athlons are 80686 even though some are 32-bit and 64-bit processors.

There are some 80486 (I think 80486DX2-66 or 80486DX4-120) that are or the right term were faster than 80586 (aka Pentium).

Have look at http://www.sandpile.org for information.

BTW, search this forum for other posts that has similar topics as this one.

Just a note for future reference. Try arch at the command line.
Best to you!

just open control panel (KDE) and at the right, shows you i686, i586, etc

Thanks, Carrie!
That is a great tip for more effectively using KDE. One of the nice things about these forums is that we learn a lot from each other. KDE is one of my favorite things about Linux and I never even thought to look there for that type of info. Although I was not the one to ask the question, I just learned something new from you!
S.