What is UNIX?

UNIX is an operating system. The operating system to organize the different parts of the computer - the processor, the on-board memory, hard drives, keyboards, video monitors, etc. - to perform useful tasks. The operating system is the master controller of the computer, the glue that holds together all the components, including administrators, programmers and users. If you want the computer to do something for you, how to run the program, copy the file, or display the contents of a directory, an operating system that must perform those tasks for you.
Most of all, the operating system allows the computer to its distinctive characteristics. It would be difficult to distinguish between two very different computers, if they were running the same operating system. On the other hand, two identical computers running different operating systems, it is completely different to the user.

UNIX was created in the late 1960s in an effort to provide multiuser, multitasking system for use by programmers. UNIX design philosophy was to provide a simple but powerful tools that can be combined in a flexible manner to perform a wide range of tasks.
UNIX operating system consists of three parts: core, standard utilities, and system configuration files.
The kernel
The kernel is the kernel of the operating system UNIX. In principle, the core of a large program that is loaded into memory when the machine is turned on, and it controls the allocation of hardware resources from now on. The kernel knows what hardware resources (for example, the processor (s) on-board memory, hard drives, network interfaces, etc.), and he has the necessary programs to talk to all devices connected to it.
The system configuration files
The configuration files read by the system kernel, and some of the standard utilities. UNIX kernel and utilities flexible programs, and some aspects of their behavior can be controlled by changing the default configuration files. One example of the configuration files of the system file table is "Fstab", which tells the kernel where you can find all the files on your disks.