Red Hat

Hi,

I am just confused about these three things which are shown in the output of uname command. I am running RH lINUX 9.0 on hardware having Intel HT CPU. My uname shows

uname -p i686 (processor)
uname -m i686 (machine)
uname -i i386 (hardware)

I was about to install some source packages but didn't know which one of i686 or i386 should I choose.

What exactly is the concept of these three. Firstly please explain what is i686 and i386. As I know i386 is the old processor architecture and i686 is the latest one. Detailed explaination is appreciated !

Thanks and regards,

Dexter

The terms are used interchangeably on a lot of Linux distros. 386 was the first popular CPU architecture in the line their current processors descend from. Since it's an Intel processor they're referring to they prefix it with a lower case "i". It's since become a shorthand way of referring to "386-family processors" or at this point "Intel-style processors."

So "i386" means technically the Intel processor that came out in the mid-80's but it's more general than that in the FOSS world. After 80386 I believe Intel released a 80486 and a 80586. So "i686" (being a model number they hadn't reached by the time they stopped making the 80x86 processors) is a shorthand way of saying "386-style processor but newer than that specific line" Which usually means Pentium since that's what came later.

So technically i686 is a subset of i386, but at this point you're not going to run into a "i386" processor that is from the 80's so the terms are used interchangeably.