What is Unix & Types of UNIX?

What is Unix?

UNIX is associate degree OS that was 1st developed within the 1960's, and has been below continuous development ever since. By OS, we have a tendency to mean programs that do pc work. it's a stable, multi-user, multi-tasking system for servers, desktops and laptops.

UNIX systems even have a graphical programmer (GUI) almost like Microsoft Windows that's straightforward to use within the atmosphere, however, the operation needs data of OS, that isn't coated by any graphical program, or once there's no Windows interface out there, for instance, in a very telnet session.

Types of UNIX?

There area unit many alternative versions of OS, though they share similar similarities. the foremost common types of OS area unit Sun Solaris, antelope / UNIX and MacOS X.

The OS OS is formed of 3 parts; Kernel, Shell and Program

The kernel

The kernel of UNIX system system | operating system | OS is that the hub of the operating system: it allocates time and memory to the program and handles file stores and communications in response to system calls. As associate degree example of the means shell and kernel work along, suppose a user sort ram my file (which has the result of deleting the file my file), the shell program searches the file store for files containing ram, then the program on my file requests the kernel via a supervisor call instruction to execute rm. once the method ram my file is finished, the shell returns the OS cubicle to the user, indicating that it's looking ahead to more commands.

The shell

The shell acts as associate degree interface between the user and therefore the kernel. once a user logs in, the login program checks the username and word, then starts another program known as Shell. Shell may be a program line interpreter (CLI). It interprets commands in user sorts and arranges to exclude them. The commands themselves area unit programs: after they end, the shell provides the user another hint (% on our system).
The good user will customize their own shell, and therefore the user will use completely different shells on constant machine. The employees and students within the faculty have tact shell by default. Tact shell has some options to assist user inputting commands. By writing a locality of the file name completion, a command, the file name, or the directory name, and pressing the [Tab] key, the tcsh shell can mechanically complete the remaining name. If the shell starts over one name with the letters you typewritten, it'll beep, prompting you to blood group few a lot of letters before pressing the key.

History - The shell maintains a listing of the commands you typewritten. If you wish to repeat a command, use the pointer keys to sort or down the list for a listing of previous commands.

Why use Unix?

Unix was developed on the premise of Philosophy that the facility of a system comes from the link between programs, not programs themselves, OS programs area unit written to try and do employment well, and programs area unit written in order that They work along, thus, OS developers increase simplicity, movability and clarity in style. To follow this Philosophy, OS systems area unit characterized by -

1. Use of text files for knowledge storage.
2. A hierarchal filing system.
3. A large variety of tiny programs move along through a command-line interpreter.
4. Use of shell script.
5. Captive programmer is avoided.
6. Use of application-oriented language in in operation systems.
7. Hierarchical filing system.
8. Its syntax got wide use for normal expressions.
9. Unix shell impressed several program line interpreters UN agency came when it.
10. C programing language became a lot of omnipresent.
11. Helped to contribute to the explosion of the net by creating protocol / scientific discipline protocols a lot of wide out there.
12. Contributed to the launch of the free package movement.

You can see the utilization of UNIX everyplace. it's dominating our servers, desktops, smartphones and even utilized in some electrical appliances like refrigerators.

Some individuals think about OS and UNIX to be Synonyms, however this can be not true. several in operation systems were developed like OS, however none of them gained quality as UNIX. UNIX may be a a twin of OS. it's several options almost like OS, however there area unit some major variations. Before UNIX and Windows, OS dominated the pc world. OS is ​​a copyright name and IBM genus Aix, HP-UX and Sun Solaris area unit the sole UNIX system system  |operating system | OS operating systems.