Linux is, in simplest terms, an operating system. It is the software on a computer that enables applications and the computer operator to access the devices on the computer to perform desired functions. The operating system (OS) relays instructions from an application to, for instance, the computer's processor. The processor performs the instructed task, then sends the results back to the application via the operating system.
Linux is very similar to other operating systems, such as Windows and OS X. Linux has grown to become a force in computing, powering everything from the New York Stock Exchange to mobile phones to supercomputers to consumer devices.
As an open operating system, Linux is developed collaboratively, meaning no one company is solely responsible for its development or ongoing support. Companies participating in the Linux economy share research and development costs with their partners and competitors. This spreading of development burden amongst individuals and companies has resulted in a large and efficient ecosystem and unheralded software innovation.
Over 1,000 developers, from at least 100 different companies, contribute to every kernel release. In the past two years alone, over 3,200 developers from 200 companies have contributed to the kernel--which is just one small piece of a Linux distribution.
(Q) What distro is best for me?
There are many different versions of Linux, and unlike other commercial operating systems that are controlled, distributed and supported by only one company, the core of Linux is free to distribute and use. This creates a situation in which numerous companies, organizations and individuals have developed their own specific version of the Linux operating system. When these versions are made publicly available for use, they are known as distributions.
Use 64-bit, unless you have a specific and good reason to use 32-bit or the processor doesn't support it..
In a 64-bit system, applications use more RAM than the same applications in a 32-bit system. So if you have a computer with relatively little RAM (2 GB or less), then 32-bit is definitely the better choice. For with 2 GB RAM or less, you'll even notice the performance difference during simple, "light" home usage.
Typically 32-bit operating systems can only support up to 4 gigabytes of memory, while a 64-bit OS can theoretically support upwards of billions of gigabytes. 64-bit operating systems are limited by artificial software and hardware ceilings, but the ceilings are still much higher than a 32-bit OS. So the short answer for memory support is this: if you want more than 4 gigs of memory, you’ll need a 64-bit OS.
(Q) What is a Live cd?
A live CD, live DVD, or live disc is a complete bootable computer installation including operating system which runs in a computer's memory, rather than loading from a hard disk drive; the CD itself is read-only. It allows users to run an operating system for any purpose without installing it or making any changes to the computer's configuration. Live CDs can run on a computer without secondary storage, such as a hard disk drive, or with a corrupted hard disk drive or file system, allowing data recovery. A live ISO is an ISO image of a Live CD which can be used in virtual machine environments, mounted as if it were a CD/DVD and used as the virtual machine's boot CD. Live CDs, ISOs, and images usually include an operating system available without charge or restrictive license such as Linux, rather than a commercial one such as Microsoft Windows, for legal rather than technical reasons.