Question-1 What is Unix? What is Linux?
- UNIX is a powerful operating system originally developed at AT&T Bell Labs.
- It is very popular among the scientific, engineering, and academic communities due to its multi-user and multi-tasking environment, flexibility and portability, electronic mail and networking capabilities, and the numerous programming, text processing and scientific utilities available.
- The UNIX system is mainly composed of three different parts: the kernel, the file system, and the shell.
- The kernel is that part of the system which manages the resources of whatever computer system it lives on, to keep track of the disks, tapes, printers, terminals, communication lines and any other devices.
- The file system is the organizing structure for data. The file system is perhaps the most important part of the Linux operating system. The file system goes beyond being a simple repository for data, and provides the means of organizing the layout of the data storage in complex ways.
- The shell is the command interpreter. Although the shell is just a utility program, and is not properly a part of the system, it is the part that the user sees. The shell listens to your terminal and translates your requests into actions on the part of the kernel and the many utility programs
- Linux is a freely available, open source, Unix-like operating System. Written originally for the PC by Linus Torvalds (A young student in the University of Helsinki), with the help of many other developers across the internet.
- Linux now runs on multiple hardware platforms, from the smallest to the largest, and serves a wide variety of needs from servers to movie-making to running businesses to user desktops.
Question-2 Explain the Features of the UNIX in detail.
The following features are provided by the UNIX operating System.
- Linux source code is freely available and it is community based development project.
- Multiple teams are working in collaboration to enhance the capability of Linux operating system and it is continuously evolving.
Multi user capability
- In a multi user system the same computer resources hard disk, memory etc are accessible to the many users.
- Users are given the different terminal to operate, a terminal in turn, is a keyboard and a monitor. All the terminals are connected to the main computer whose resources are available by all users.
- So the user at any of the terminals cannot use only the computer but also any devices that may be attached like a printer.
- It means that it is capable of carrying out more than one job at the same time it allow you to type in a program in its editor while simultaneously executes some other command you might have given earlier.
- Say for example you might have given earlier sort and copy a huge file this job will perform in the background while in foreground you use editor.
- This is managed by dividing the CPU time between all processes being carrying out.
- UNIX has the excellent communication with the users. The communication may be within the network of a single main computer or between two or more such computer network.
- The users can easily exchange mail, data, and programs through such networks.
- Unix Has the three provisions for protecting the data. The first is provided by assigning the passwords and login names to the individual users and ensuring that nobody has excess to your work.
- All the five have the read write and execute permissions to each file which decide who can excess a particular file, which can modify and execute it.
- Lastly there is a file encryption utility which encodes your file into an unreadable format so even if someone succeeds in opening it your secrets are safe.
- Portability means software can works on different types of hardware in same way.
- It is one of the main reasons for the popularity of the Unix. It can be ported to almost any computer system with only the minimum adoptions.
- A portability credit of the UNIX is because of the C language, it written in C language and C language is portable.
Question-3 Give comparison of UNIX and Windows Operating System.
UNIX is a open source operating system (we can modify the code), easily available free of cost. Windows requires licensing and is a paid operating system.
- UNIX is a command based operating system while windows is menu based.
- In UNIX I/O components are stored as file while windows does not support this functionality.
- Windows must boot from a primary partition. UNIX can boot from either a primary partition or a logical partition inside an extended partition.
- Windows allows programs to store user information (files and settings) anywhere. This makes it impossibly hard to backup user data files and settings and to switch to a new computer.
- UNIX is CLUI (Command Line User Interface) operating system while a window is GUI (Graphical User Interface) Operating System.
- Windows program are event driven i.e. main program waits for some events to happen and calls a procedure to handle it. In contrast unix program consist of code that does something or makes system calls to get some services done.
- In UNIX there is one to one relation between system calls and library procedures, while in windows library calls and system calls are decoupled. Win 32 API(Application Program Interface) are used to get operating system services.
- UNIX supports various functionality as linking files, mounting and unmounting of files,file permissions using chmod command, which are not present in windows.
- UNIX is less affected by viruses and malwares and hence more secure compared to windows.
- Examples of UNIX operating system are Ubuntu, Fedora, Red Hat, Debian, Archlinux ,Androidetc while examples of windows operating system are Windows 8, 8.1, 7, Vista,XP.
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