Introduction to Unix/Linux Operating System
A computer is an electromechanical device used to process, store, and distribute information. This machine is made up of both the hardware and software components. The monitor, CPU, input and peripheral devices are examples of hardware components of a computer while the memory, Operating System (OS), and programs make up the software part of the computer. When the computer boots up, the CPU receives instruction from the BIOS (Haldar, & Aravind, 2010). The received instruction directs the computer through a number of stages that ultimately loads the operating system. From this point onwards, the OS takes over functions that include standardized interfaces, resource management, and multi-tasking. Two of the commonly encountered operating systems are UNIX/Linux and Windows OS. The essay that follows discusses various aspects of the UNIX/Linux OS.
An OS is a resource manager, which takes the form of application programs that allow users to access system resources. The OS allows safe access to the printer by limiting the number of applications and users that can access the printer at any one time. Efficiency of the CPU is ensured by the OS suspending all programs that are yet to receive the input/output (I/O) command. This ensures that the running programs are allowed sufficient memory space for optimum operations (Christian, & Richter, 1994). Additionally, an OS affords convenient interface that allows users to perform their functions without getting to interact directly with underlying hardware and software.
Brief History
The design of the UNIX OS began in the early 1970s and was led by Dennis Ritchie, Ken Thompson and others working from the AT & T Bell Labs. The work on the development and refinement of the UNIX OS continued through the 80s and by 1990, several variants of the OS had been developed by various entities. The massive number of variants then ushered in the formation of the IEEE POSIX standard that initially defined the API before it eventually took over all aspects of the UNIX system that included utilities, commands, and standard libraries (Love, 1995). Following this was the evolution of POSIX into the modern day Single UNIX Specification (SUS).
Around the same period, the GNU- a UNIX-Like operating system was developed. This operating system developed and used free software. Users of this OS were at liberty to share and improve the free software they used in the system. This whole project was initiated by Richard Stallman. The purpose of this innovation was to allow users access to free software, which they could modify, copy, and redistribute free of charge and without any restrictions. All free software run by the system was governed by the GNU General Public License (GNU GPL), which dictates that all source codes released under the GPL are free and without restriction and subsequent modification or improvements should also be redistributed on the same terms of no restriction (Spafford, 1995).
Linux OS evolved from the UNIX OS. It began in 1991 as a hobby kernel for Linus Torvalds. This new OS became POSIX compliant and received a GNU General Public Licence. The modern day Linux is a combination of the Linux kernel and the GNY project software. Variants or distributions of the Linux OS include SUSE, Fedora, and Ubuntu among others. The GNU software upon which the Linux OS operates is extensive and includes everything ranging from compliers to editors to desktop graphical user interfaces (Flynn, & McHoes, 2001).
Users and Groups
The UNIX/Linux OS was created around the concept of multiple users. Each user is assigned a set of files to work on and has the power of determining whether other users can access, view, execute, or modify the files. Users may be united in a group and one user is free to belong to multiple groups. Groups are important because they allow users to permit specific access to members of their groups.
The users and groups in a Unix/Linux system are identifiable by names that are mapped using the unique user and group ids. The files on the system disk have user and group ids associated with them and these define the ownership of the files. A root user is a special user of the UNIX system who has administrative capabilities and can access all files and functions on the system. This user can change or configure the network and modify the system policy and settings (Alpern, & Alpern, 2005). A root user can also edit critical files and delete files from the system. Normal users can only edit the files they own or the files they have been allowed by other users to work on.
Components of the UNIX OS
The UNIX OS comprises three major parts; the kernel, shell, and the programs. The Kernel acts as a hub for the operating system. As a hub, the kernel is tasked with the responsibility of allocating memory and time to programs and it handles storage of system files and oversee communications in response to system calls. The Shell is a command line interpreter (CLI) which interprets the commands typed in by the user into a language that will be understood by the computer (Silberschatz, & Galvin, 2013). The commands typed in are programs that facilitate communication between the user and the computer.
Features of the UNIX Operating System
The UNIX OS has three basic features; it is portable, can be used by multiple users at one time, can multi-task. These features work together to afford UNIX high functionality capabilities. Only the kernel is written in the assembler and has many support tools. The system’s hierarchical directory structure supports the maintenance and organization of files. The OS allows more than one program to be run at one particular instance. Additionally, many users working from different terminals can use one machine (Peek, & Todino, 2002).
Functions of the UNIX Operating System
UNIX is considered as the earliest foundation of internet networking and communications. The UNIX OS is an old operating system renowned for its reliability and stability. Different implementations and distributions of the UNIX system exist; Berkley Standard Distribution (BSD), Hewlett- Packard’s HP/UX and the IBM’s System V. These distributions show some semblance in their functions and design. The architecture of the UNIX system makes it very stable. This architecture is designed on software and hardware layers. At the bottom of the architecture is the hardware system upon which the software system runs (Linux Line, n.d.). A kernel layer rests in between the higher computer functions and the system hardware. This kernel mediates between the functions and the base-level hardware. Commands and applications also interact with the kernel (Flynn, & McHoes, 2001). The system uses a shell, GUI, or command line interface to run applications and execute commands.
UNIX is commonly used as the server operating system of choice. In this function, the OS allows multiple users to access resources on the server from their remote computers that are connected to the server via terminals. An established UNIX server requires minimal administrative interactions and uses the shell to allow access to the server and applications located there in. Seldom does the server implementation running on UNIX use GUI systems and common windows systems (Christian, & Richter, 1994).
The UNIX OS can also be installed in high-end workstations used in specialized fields that include computer aided design and modelling, engineering, graphic design, and computer animation. Most of these workstations use some sort of a GUI or windowing system that is user-selectable. The users can choose the system that they prefer to work with. The windowing system is anchored on the shell system, a feature that allows users of GUI-based UNIX to gain access to the shell as well (Christian, & Richter, 1994).
How UNIX relates to other operating systems
UNIX OS is a perfect example of an operating system. Other common examples include the Widows OS, DOS, and Mac OS. Each of these operating systems perform the same function i.e. they mediate all input, processing and output processes of a computer. However, it would appear that UNIX has a clear advantage over most of these operating systems. UNIX is stable and does not crash as often as Windows OS. UNIX is as easy to use as Windows OS; it offers the user a command line and a GUI. UNIX is more reliable than Windows and it requires lesser administration and maintenance than Windows. Another advantage of the UNIX OS over Windows OS is in the fact that UNIX can support multiple users while Windows OS only supports one user at a time. Another important difference between UNIX and other OS is that the software running the UNIX system is free and their redistribution is not restricted. In Windows OS, the software used is developed by Microsoft and it is costly to purchase all the software needed to have a computer running (Cai, 2012).
The comparisons and relationships between UNIX OS and Windows OS apply to all the other OS. Additionally, the following merits can be said to relate to UNIX OS; it exhibits excellent control and use of system resources, it is highly reliable, does not require periodic reboots, and comes with free software. There is no need for software licensing, has better scalability compared to other operating systems and it is readily available in a downloadable format from the internet and open source databases. Clearly, UNIX is far more superior and advantageous compared to the other operating systems (Garfinkel, & Spafford, 2011).
The business impact/use of UNIX in enterprise companies
The use of UNIX in a business environment is beneficial in a number of ways. Firstly, UNIX can support multiple users connected to the system via terminals. This means that the organization will not need to invest heavily on multiple computers. A high-end server can be installed in the organization and have all the other computers connected to this server via terminals. This is important because all users can get access to common data and work done by one user can easily be audited by the other users in the group. Connection of users to a centralized UNIX server also allows for the sharing of scarce resources. Peripheral devices such as scanners and printers can be connected to the server and be accessed by the users from their workstations (Goethals et al, 2004).
Secondly, unlike Windows OS that requires periodic maintenance, UNIX does not require these maintenance and administration; this cuts down on the costs related to administration of the system. The UNIX OS can operate continuously without crashing or needing reboot. This allows users to work continuously without system drags and collapses that are synonymous with Windows OS. Operating system instabilities associated with Windows OS attracts most business owners to the UNIX OS. UNIX allows businesses to enjoy uptimes of up to 99.99% available service requirement; this is appropriate for businesses processes that require nonstop support for vital services and applications (Goethals et al, 2004). .
The UNIX OS is also considered more secure than other operating systems. However, this does not mean that it is 100% secure. The difference between the securities provided by UNIX OS relative to those provided by other operating systems is in the fact that UNIX relies on the worldwide community for security patches. These patches are timely and more refined because they originate from a myriad of sources (Gunn, 2000). Moreover, the UNIX OS restricts access to the system to persons with unique ids. Users are allowed access to files that they own and those that they have been allowed access to by other users. This helps in ensuring that the system files are secure (Gunn, 2000).
UNIX is widely used in the modern day business. Its scalability and flexibility allows most businesses to support their operations around the OS. Its security and manageability also makes it ideal for use by large websites and company’s e-commerce, Business-to-Business, and Business-to-Consumer platforms (Amit, R., & Zott, 2001).
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