CPU architecture

A system's CPU architecture is generally 32-bit or 64-bit. When you download the VirtualBox or Vagrant software package-installer, you will have to define which version you require. 

The easiest and quickest way to find out the CPU architecture for a Ubuntu system is to go into the Terminal and run the uname -mrs command.

You should now see some output on the screen. What we are looking for is the last part; in my case, it is showing x86_64.

This is showing that I have a 64-bit CPU architecture. If your system is a 32-bit one, you would likely see either i686 or i386.