An Operating System is a software program that runs on a computer and enables the computer hardware to communicate and operate with the computer software. An Operating System is the first thing that is loaded onto a computer without which a computer would be useless. Operating Systems provide a software platform for the application programs to run. Microsoft Windows, Mac OS X, GNU/Linux are examples of popular modern operating systems being used in personal computers. The diagram below represents an operating system as the core of a computer's application and peripherals:
Classification of Operating Systems:
Multi-User: Multi-User operating systems allow two or more users to access the same operating system at different machines and run programs on his/her computer at the same time. Common examples of multi-user operating systems are VMS, UNIX, and mainframe operating systems which includes the MVS system.
Multi-Processor: Multi-Processor operating systems are capable of utilizing and supporting two or more central processing units (CPUs). Linux, UNIX and Windows are examples of Multi-Processor operating systems.
Multi-Task: Multi-Tasking operating systems allow multiple software processes to run at the same time. This is done by dividing system resources between the tasks or processes and switching between the tasks while executing. UNIX, Windows 2000, Windows XP and Mac OS X are a few examples of multi-tasking operating systems.
Multi-Thread: Multi-Thread operating systems allow different parts of the same software program to be run concurrently. This speeds up the execution process. Windows 2000, Linux and UNIX are typical examples of such systems.
Real-Time: Real-Time operating systems are designed to run applications with a specified time constraint and high degree of reliability to prevent failures. The most widely deployed real-time operating systems are Windows CE, IBM's OS/390, VxWorks, RTLinux, QNX.
Throughout the history of computers, the operating system has continually contributed to the needs of users and system developers. The actual usage of each operating system is based highly on the task needed to accomplish. Some users prefer a certain system to the other, some enjoy security debates and some have legitimate claims while others do not.
The name "Linux" originated from the Linux Kernel coded in 1991 by Linus Torvalds (Linux stands for Linus's UNIX), with a goal to have a free system that was completely complaint with the original UNIX. The GPL - GNU General Public License made Linux most popular as the source code can be downloaded in its entirety from the Internet completely for free. This differentiated Linux from other popular contemporary operating systems as Linux kernel and other components were made to be freely available.
The history of GNU and Linux dates back to 1983 when Richard Stallman started publishing GNU manifesto and then found the Free Software Foundation. Later, Free Software Foundation and Richard Stallman worked on a full operating system based on main components from the GNU project that resulted in what is currently known as GNU/Linux. The GNU/Linux distributions under GNU GPL license aims at a software that must be free to copy, distribute and modify.
Linux, a modular UNIX-Like Operating system, has become the most well-known open source software prevalent today, that obviates the need for programmers to keep reinventing the operations layer for each new project. Linux was the first Unix implementation targeted for microcomputers.
Open Source Platform
Open-source software (OSS) is computer software that is available in source code form for which the source code and certain other rights normally reserved for copyright holders are provided under a software license that permits users to study, change, improve and at times also to distribute the software.
OSS is provided with a license that gives the end user the right to use it freely for private or commercial use unlike standard commercial software which is distributed in a binary format (i.e. an .exe file), with very limited rights to use or distribute it. Open Source offers the following benefits:
Security flaws and bugs are identified more easily
Increase in the number of users/developers in turn increases testing, identifying and fixing more bugs in the software
Software is easily adapted beyond the original authors conception
Businesses can achieve greater penetration in the market and gain competitive advantage
Reduced cost on marketing and logistical services
A developer or an author achieves recognition by making his/her code publicly available
The user has the right to inspect and even modify the underlying source code. This opens doors to software developers to come up with additional functionalities (add-ons) and new abilities that complement the core functionality of the existing software. The release of source code allows external observers to inspect the internal functions of the program, which means you can be confident that your private data is not being spied on or utilized by others.
A major problem with proprietary software is that it tends to use closed file formats to store data. Once the parent company stops supporting older versions of a proprietary program, users are forced to go for an upgrade to a newer version of that program, at significant expense, in order to retain access to existing data. This is not the case with an OSS, as third party vendors can easily write an import filter for the next generation of software, ensuring that your data will always be available.
The characteristics and release of open source software has resulted in more prominent organizations and developers heading towards the OSS development which includes some of the following open source initiatives such as:
Apache web server
OpenOffice.org and Java from Sun
Linux also ranks among the first or the second most popular operating system software for Internet servers, accounting for about 30% of all Web servers in the world today. Due to a fairly less awareness on its intended use and installation concepts, it is rarely used as a client operating system. However, Linux can be used on a wider range of computer platforms than any other operating system and is more secure than the commercial OSS available in the technology space. Also, the cost associated with an open source software, like Linux, are relatively less compared to other commercial operating system software
From a historical perspective, it has been identified that open source and free software initiatives have together altered the operating system software markets fundamentally in the recent years. As Richard Stallman puts it, "Open source is a development methodology; free software is a social movement." Critics have commented that today the main operating system alternatives either fully or partly foster the concept of open source UNIXes or Microsoft.
It is indeed difficult to draw a comprehensive picture on how open source and free software actually work as competitive tools. Given below are some facts on the same:
Open source code and free software are proved to be powerful ways to standardize and stabilize new operating system technology and compete against established market powers
Their impact on desktop markets has been limited mainly because of compatibility and usability issues
The server and enterprise application markets have seen more changing impacts based on their benefits of standardized independent technology and other technical features
Open source impacts are yet to reflect on both desktops (e.g. user interface) and servers (e.g. enterprise applications) from where proprietary vendors can generate revenue