Techie Blogger

We are very familiar with Linux and its relation with UNIX. But most us of don’t actually know what are differences between the two.
Linux is called Unix-like and is not a true Unix operating system. Linux is a Unix clone written from scratch by Linus Torvalds.
Unix is popular operating system, developed by AT&T in 1969 whereas Linux was first released in 1991. Note that the time difference between the introduction of the two is a long 22 yrs. It is a myth that Linux is a GUI for the UNIX core. However, GNOME and KDE are GUIs for GNU/Linux. UNIX is the foundation for a number of operating systems, with Linux being the most popular one.

1.DIFFERENT AT THEIR KERNEL LEVELS
UNIX kernel is not freely available. So a geek, named Linus Torvalds, at the age of 21 sat down and wrote a kernel right from scratch borrowing ideas from UNIX. This later came to be known as Linux Kernel which he licensed under the GPL (GNU General Public License). Linux kernel is freely available. Hence Linux is called UNIX-like. He later said in an interview that “This is the best thing I have done in my life”.

2.HARDWARE
Linux runs on many hardware platforms, including Intel x86 computers. On the other hand, UNIX is proprietary-hardware-bonded and this hardware is much more expensive than a typical PC.
Unix requires a more powerful hardware configuration. It will work in large mainframe computers but not in an x86 based personal computer. Linux will work on both a large mainframe computer and an x86 based personal computer.
Putting it in simple words, UNIX will not run in the normal desktops or laptops that most of us use.

3.LICENSE
Unix is a proprietary software and you would need to buy it if you want to use it.
GNU/Linux is licensed under the GPL (GNU General Public License) which is an open source license. This means that the kernel-code is available for anyone to use or change as long as the changes are again licensed under GPL.

4.LINUX – JUST A KERNEL & UNIX – A COMPLETE OS
Linux is just a kernel. All Linux distributions (Fedora,Ubuntu,OpenSUSE etc.) includes GUI system,GNU utilities and various other applications (such as OpenOffice, Firefox) and of course the kernel. It is the distributions that make Linux a complete, usable Operating System.
However, UNIX operating systems are considered as complete operating systems.

5.EASE OF USE
Linux was built with the common user in mind, therefore most Linux distributions provide users with a very capable GUI ( that also eats up a portion of the computer’s processing power). Owing to Linux’s flexibility, the GUI can be removed.

6.SUPPORT FOR FILESYSTEMS
Most commercial version of UNIX supports two, or possibly three, different local filesystem types. Linux, however, supports almost all of the filesystems that are currently available on any operating system.

SIMILARITIES

• Both Linux and UNIX use same shells (eg. bash and korn).
• Both are capable of using a command line and a GUI.
• Linux is used in many applications that need to maintain up-time because Linux, like UNIX, can run for months at a time without rebooting. While the typical method of solving Microsoft problems is to “reboot”, that particular requirement does not seem to be appropriate in a Linux/Unix environment.

Appendix

Having said so much about kernel, let us see briefly what actually a kernel is.
Kernel is a bridge between applications and the actual data processing done at the hardware level. Its responsibilities include managing the system’s resources. Hence it forms the most vital part of an operating system.
A kernel has facilities to receive requests (eg.commands from user) and grant access to resources such as allocating space for a new file or creating a network connection (which mainly deals with hardware). Kernels use a system call (or syscall) interface to handshake with applications [Applications ==> syscall(INTERFACE) ==> Kernel]. At the user level the device details are not visible. The kernel recognizes what a device is (eg. I/O devices,RAM etc.) and how to communicate with it at the lowest level.
Generally, the boot loader starts executing the kernel in supervisor mode. The kernel then initializes itself and starts the first process. After this, the kernel does not typically execute directly, but only in response to external events (e.g., via system calls used by applications to request services from the kernel).

But no matter  what  OS you end up  using  in creating your websites, most likely, they  will be compatible with most of the hosting methods available