What is UNIX?
UNIX OS is not an Open Source OS, and also nowadays it is a pure Unix Operating System. This UNIX is an Operating System, which the developers developed in the 1960s, and has been under constant development ever since. Unix is a portable, multitasking, multiuser, time-sharing OS. We mostly use this UNIX system. In PCs, servers, and mobile devices. The Unix environment was also an essential element in the development of the Internet and networking.
UNIX systems are :
The use of text files for data storage :
- A hierarchical file system.
- A large number of small programs string together through a command-line interpreter.
- Use of shell scripts.
- The avoidance of captive user interfaces is in stock.
Unix had a significant impact on other OS and can be credited in whole or in part for the following:
- The use of high-level language in operating systems
- Hierarchical file systems
- Its syntax for regular expressions found widespread use
- Unix shell inspired many of the command line interpreters that followed
- C programming language became more ubiquitous
- Began the movement toward modularity and reusability in software engineering
- Helped contribute to the explosion of the Internet by making TCP/IP protocol more widely available.
- Contributed to the launch of the free software movement
UNIX is a trademark. AT&T owned it, then it got sold and sold and sold and now needs a web search to find out its owner and track its ownership history. Open Group certifies an Operating System to be “UNIX” or lack of it. So, Solaris, HP UX, IBM AIX, Mac OS X (yes!) are all certified UNIXes. These are not free and indeed not open source. Solaris has an open-source version for x86 architecture.
The UNIX OS is made up of three parts:
- The kernel.
- The shell.
- The programs.
The kernel :
The kernel of UNIX is the hub of the OS: it allocates time and memory to programs and handles the file store and communications in response to system calls.
The shell :
The shell acts as an interface between the user and the kernel. When a user login. The login program checks the username and password and then starts another program called the shell. The shell is a command-line interpreter (CLI). It interprets the commands the user types in and arranges for them to be carried out. The controls are themselves programs. When they terminate the shell gives the user another prompt (% on our systems).
The programs :
UNIX programs are the software of the UNIX OS. It can use Operating service, Utility, and other Application service software.