32 bit Vs 64 bit OS architecture in Linux

Importance of architecture

 In Linux you need to know the architecture of your underlying OS especially in a rpm based distro as:-

• Software packages are specifically prepared and targeted at specific architecture.
• Installation paths for the binaries are different architectures.
• It is believed that there would be major performances differences if the correct version of package is used on a machine compared to incorrect one.

Types of software packages

• 32 bit packages are generally named as *i386*.rpm , *i586*.rpm, *i686*.rpm. It is possible that though your CPU is 64 bit you may be  running a 32 bit OS. Please consider avoiding installing packages of type *i386*.rpm as Linux is going to remove support for them starting with kernel version 3.8. Also i386 packages may perform poorly when installed on modern day machines.
• 64 bit packages truly support 64 bit addressing and are generally named as x86_64*.rpm.

64 bit vs 32 bit OS

 If it comes to choosing an OS  version to install you need to consider doing the following:-

• Check whether your CPU supports 64 bit or 32 bit addressing. The booklet that you get when you purchase your machine will help you in this regard. Most of the newer generation machines do support 64 bit addressing.
• Download Live ISOs of both kinds (32 as well as 64) and test them on your machine without installing the OS itself. You can get 32 bit as well as 64 bit ISOs for many distros. For example, you can download stable versions of openSUSE from this page. Sample download page is shown below.

• Check whether all the software you need on a day to day basis are available as 32 or 64 bit rpms. This may be the Go or No-Go for deciding on the version of OS unless you are willing to compile and install your software packages. For example, you many find that in software.opensuse.org "google-earth" is  offered only as a 32 bit rpm.

Check version of OS you use

 There are various way to check the OS architecture. For starters, I am running a 64 bit OS and use GNOME 3.4.2 / openSUSE 12.2 .On my machine i can check my OS info in following ways.

Using CLI

 All you need to do to check the OS version is to run the command "arch" in terminal. You can use the command "gnome-terminal" in command launcher (Alt+F2) to open the terminal and use the "arch" command.

Sample output on 64 bit OS

Sample output on 32 bit OS

Using GUI

 I can check the my OS version by checking info from Gnome System Monitor in the "System" tab.  I open command launcher (Alt+F2) and use the command "gnome-system-monitor" and i can check all the relevant details as shown below.