Importance Of Unix Operating System Information Technology Essay

UNIX is a powerful and very popular operating system which is widely used in both workstations and servers. The UNIX environment and the client server program were very important for the development of the internet and the remapping of the computer systems as keep key frame of NETWORKING rather that the individual computers.

It was developed but the AT&T which distributed to the government and the academic institutions due to which it is been used widely in variety of the machines than any other operating systems.

UNIX was designed to be more portable, multi-user, and multitasking in a time sharing configuration. UNIX systems are classified in various concepts the first part is the PLAIN TEXT for storing data. The second part is hierarchical file system. The Third points are treating devices and certain inter process communications (IPC) as file. The forth part is use of large number of software tools in other words it can be classified that small programs that can be connected together through a command line interpreter using pipes, as it does not want to use single monolithic program that includes all of the same functionality.

WHAT IS UNIX

In UNIX there are several layers of interaction which are occurring between the computer hardware and the user. The first layer is kernel, which runs on the actual machine hardware and deals with all the connections with the hardware. All the commands and applications in UNIX relate with the kernel, rather than the hardware directly. The hardware constitutes the second layer. On top of the applications and commands is the command-interpreter program, there is another layer which is called shell which interacts between user, user’s applications, and the existing UNIX commands. In most of the cases the UNIX commands are UNIX programs, distinct from the kernel. A final layer is a windowing system such as X. The windowing system interacts with the shell, but it also interacts directly with applications. The final “layer” is user, the user. User will face with the whole operating system through just the shell, or through a combination of the shell and the window system. The figure below gives a representation of the layers of UNIX.

Under the UNIX, the operating system consists of many of the utilities along with the master control program, the kernel. The kernel is a powerful program which helps the UNIX to start or stop program and handle the file system and other common lower level tasks which every programs shares. The kernel also provide an important advantage of scheduling access to the hardware to avoid conflicts if two program try to access the same resource or device at the same time. To control such access that has to be given special rights on the system this leads in the division between the user-space and the kernel space. The Microkernel concept was introduced in the mean time to reserve the trend towards the larger kernel and return to the system in which all the tasks were completed by the smaller utilities.

UNIX kernel

The kernel structural design must support the primary UNIX requirements. These requirements have two categories functions for process management and functions for file management. Process management entails allocation of resources include in CPU, memory, and offer services that processes should need. The file management itself involve managing all the files needed by processes, communication with device drives and regulating transmission of data. The kernel operation gives the user processes of synchronous operation, hiding all underlying synchronism in peripheral and hardware operations. The kernels handle following points.

1. It is responsible for scheduling running of user and other processes.

2. It is helpful in allocating the memory.

3. It is responsible for managing the swapping between memory and disk.

4. It is responsible for moving data to and from the peripherals.

5. It receives service requests from the processes

All the services are provided by the kernels through a call to the system utility. As a result, kernel by itself is rather a small program that just maintains enough data structures to pass arguments receive the results from a call and then pass them on to the calling process. Most of the data structure is tables. Kernel also aids in carrying out system generation which ensures that UNIX is aware of all the peripherals and resources in its environment.

About UNIX Directories

Directories in the UNIX operating system have name and path. Directories can also contain files and folder. Rules which apply on the files are applied on the folder as well. The files and the folder contained in the UNIX operating system are stored as the hierarchical tree structure. Its direction of the tree goes upside-down, as in the figure below.

UNIX Directory Structure

In the unix operating system at the top of all the directories there is always a root directory. The name of the directory is ” / ” (slash) character. After the root directory there are couple of more directories such as bin, stc, dev, tmp, pub and usr. And other directories can be branched out as well but it is not possible with the above mentioned directories

Displaying Directories

When you log in in the unix operating system then you are placed in the home directory. There is a command which helps in displaying where are you in the file system and what is the path of the file it is pwd command which helps in getting the above mentioned job done. Another command is there wich will help you in displaying the content of the home directory the command is ls which will help us to do the above mentioned things.

Copying Files to Other Directories

By using the mv command you can copy the files to the other directories.

cp sample.txt ~/projects

using the mv command the name of the file will be same as the parent directory until you change it.

cp sample.txt ~/projects/newsample.txt

Renaming Directories

If u want to rename the exixting dectory then use the mv command:

mv oldDirectory newDirectory

The new directory must not have the file name which is not being used any time before. The name directory which you are using must not be the current directory and the directory which has been created can be circulated anywhere in the file system.

Removing Directories

If u want to remove the directory then you have to be in the parent directory. Then use the rmdir with the name of the directory. You cannot remove a directory with rmdir until you delete all the file within the same directory. This helps you from an accident in which you remove your important files if it has been stored in the folder which you deleted. You can erase all the files in a directory by going to that directory use cd command and then using rm command remove all the files in that directory. The fastest way to remove directory and all of its files and subdirectories and their contents is to use the rm -r for recursive command along with the directory’s name.

CONCLUSION

In this assignment I have talked about the system of UNIX and the entire process taking place in it forms the core of the UNIX operating system. I have explained about all of the stages of the operating system. I also have explained about the kernel I feel that UNIX is the most secure operating system of all. I found UNIX more secure than the windows operating system. In this assignment i have explained about the advantages of the UNIX and i really believe that it has more advantages than the windows operating system. I have done some research on the file system of the UNIX. I have explained using commands how to display directory and copying files in the directory. It is bit difficult to manage the file system in UNIX and it is very difficult for me to remember all the stages to do a simple thing and let me tell something about commands it is very difficult to remember it. So in this a negative point of the UNIX and in case of user interface the windows operating system is more useful. But in all aspects UNIX is safer than windows operating system.

References

The introduction and all of the part is mostly referred from the following website.

http://www.rice.edu/Computer/student.html

http://www.ee.surrey.ac.uk/Teaching/Unix/unix2.html

M.Stonebank.,”UNIX Introduction”, Surrey.ac.uk.,

http://www.ee.surrey.ac.uk/Teaching/Unix/unixintro.html

www-stat.wharton.upenn.edu/…/shell-Bourne-An-Introduction-to-the-Unix-Shell.htm –

http://www.topbits.com/unix-shell.html

The content of commands of the UNIX is taken from the following statement.

http://www.cumc.columbia.edu/computers/html/unix/unix1_in.htm

The source of kernel was explained from this website

http://en.wikipedia.org/wiki/Kernel_(computing)