Operating Systems - Windows, Linux and Android - Case Study Example

Operating Systems Introduction An operating system (OS) is the software whose primary use in computing is to run the hardware and software by enabling them to communicate. Hardware refers to the tangible parts of a computer like the system unit, keyboard, mouse and hard drive among other components. The software refers to programs installed on a computer to perform specific functions. An example of software includes the office package, Adobe reader, and Acronis disk director. Although there are numerous OS on the market, this paper will focus on three of them, namely Windows, Linux and Android OS. With the help of online sources as the primary source of data, this study will analyze the above three OS in terms of their structures, components, working mechanism, and their code complexity. As such, the study be divided into; the history of the OS; and types of OS. A summary of the study will be provided at the end. History of OS Initially, digital computers did not have an OS. The first OS was evidenced on fourth generation computers after evolving from primitive electronic digital gadgets to large scale integration circuits and chips. With such advancements, users were able to interact with computers through a command line interface, which required a user to be vast with a wide range of commands. An OS that dominated that age, included the MS-DOS, which was a Microsoft product, developed specifically for machines with the Intel 8088 CPU and IBM machines, and the UNIX, which dominated large personal computers with the Motorola 6899 family (Mencken, 2015). Unlike that Stone Age period, technology has seen the development of most OS with a graphical user interface (GUI) and robust capabilities like multi-tasking, real-time performance, ability to operate in single user and multi-user modes among other features. The next section will detail the various types of modern OS as highlighted in the introduction Windows OS Structure Figure 1 the structure of Windows 2000 (Case Study 2: Windows 2000, 2015) As illustrated in figure 1 above, any version of Windows OS, ranging from Windows 2000 and the later version is segmented into the kernel mode and the user mode. The kernel mode runs the OS, whereas the user mode runs the environment subsystems of the OS. Precisely, the kernel is responsible for managing memory, processes, and file systems among other tasks. The environment subsystems segregate processes that facilitate the accomplishment of user tasks (Case Study 2: Windows 2000, 2015). Components The major components as seen earlier are the kernel mode and the user mode. The kernel mode has a variety of other small components, including; the Executive, which is responsible for system security, input/output (I/O) functions, and memory and thread management among other services. The hardware abstraction layer is another one and completely dissociates the OS from any hardware differences related to a particular platform. Kernel ensures that interrupt handling, thread scheduling, process switching, and multi-processor synchronization are managed accordingly. Device drivers, which comprises of the file system and hardware drivers, for translates a user’s I/O function calls into particular I/O requests of a device. The user mode includes; user applications like Win32, Service Processes like the event logger, Special System Support Processes, which are primarily services that are not part of the Windows OS and may include the session manager and login process, and the Environment Subsystem that is responsible for personalizing the OS through exposing its native services to other software that perform distinct tasks (Stallings, 2005). How it works The working mechanism of Windows OS involves separating system software from application-oriented ones. Precisely, system software run in the kernel mode, whereas application-oriented software runs in user mode and is limited from accessing system data (Stallings, 2005). Windows as the OS is a single user, but a multi-tasking OS, implying that although it only serves one user at any given time, the user can open several windows and run multiple tasks concurrently. It divides the available processor time into slices before allocating them to various processes; hence referred as a preemptive multi-tasking OS. However, once a process’s allocated time elapses, that particular process gets suspended through the context process switching to save room for other processes. During this switching, the system saves the preempted process’s context and restores the previously saved process’s context on the queue (Multitasking, 2015). Windows has an embedded family of used in the leveraging of intelligent systems solutions that are customized to perform data collection, storage, and processing for the achievement of actionable business intelligence and results. With embedded, windows become a robust OS with expanded opportunities and power that extends to edge devices (Windows Embedded, 2015). Code complexity Microsoft used a more complex code to develop its initial Windows OS. As a result, it has become more challenging to simplify the codes in the newer versions (Perrin, 2010). However, in programming, using complex codes when developing an application increases the chances of having more bugs and, therefore, creates a lucrative target for hackers (KING & BOULTON, 2015). Thus, the recent episodes of hacking evidenced in Windows platforms can be associated with the complex code used to develop the OS. Linux Structure and components of Linux Figure 2 is an illustration of the structure of any version of the Linux OS. Figure 2 the structure of Linux OS in the form of layers (Structure of a Linux Based Operating System., 2015) Linux OS like Ubuntu, Kubuntu, Mint, and SUSE has the kernel for ensuring communication between the computer hardware and the OS, performs memory and CPU allocation, and manages processes and security. There are also device drivers that are specific to the computer hardware. The standard library of procedures is another one and facilitate communication between the user’s applications with the kernel, for instance, a request from an application to the kernel to open a file for reading or writing purposes. The Standard Utilities and User Applications is also a Linux component that resembles UNIX utilities. Precisely, it is a GNU Linux project that has commands used to run applications and services, like editing and file manipulation commands (Structure of a Linux Based Operating System., 2015). How it works Linux is a multi-user and a multi-tasking OS. As such, more than one user can work on the same system and perform several tasks concurrently, using different dumb terminals, consoles and pseudo. Users also get a chance to schedule their tasks to be performed in their absence (Linux® As a Real-Time Operating System, 2015). The kernel is still responsible for dividing time into slices and allocating them to different processes, and performing context switching of the processes once their allocated time elapses so that the previous tasks can be restored on the queue. However, it should be understood that the kernel of Linux does not get preempted completely as it is the case for Windows OS. Linux is an embedded OS; thus, can leverage several packages and add new features to devices. Although it is not a real-time OS, Linux has real-time features like SCHED_FIFO for managing tasks in case there are two or more of them competing for available, but limited resources. These features are distributed in the OS’s mainstream code as patch files for the provision of real-time services to applications and guarantee maximum capabilities within a specified constraint of time (Linux® As a Real-Time Operating System, 2015). Code complexity Source code for Linux kernel can easily be downloaded and edited to come up with a new OS. Although the code might seem complicated to new developers, it can still be simplified with the help of the shell function. Thus, the simplicity of this code facilitates easy debugging and inhibits the hackers’ activities; thus Linux is more secure than windows. Android Structure Figure 3 Structure of Android OS Android OS comprises five components as illustrated in figure 3 above, including Linux Kernel, libraries, Android runtime, Application framework, and Android apps. The next section will examine these components individually. Components of Android OS and how they work Linux Kernel, responsible for interacting with the hardware as it has all the required drivers to make the hardware functional. Additionally, Linux kernel is the abstraction layer that mediates the hardware to other application layers. With this type of kernel in place, porting Android to a wide range of hardware has become easier. Libraries are the next component and are mostly developed using C or C++ to suit a particular hardware (John, 2015). The central role of libraries is to help device with data handling. Examples of these libraries include the surface manager, which compost window manager with off-screen buffering to make the window more transparency, SQLite, used as a database for storing Android data, Webkit, used as the browser for displaying HTML content, and OpenGL for 2D and 3D graphic rendering to the screen. Android runtime is made up of core Java libraries and Dalvik Virtual Machine. Dalvik Virtual Machine is responsible for running applications with little processing power and in an environment with small memory. Core Java libraries, on the other hand, are different from Java SE and Java ME libraries, even though they perform quite a number of functions defined in Java SE libraries (John, 2015). The Application Framework is another component, responsible for resource and voice call management. It has an activity manager for the management of an application’s life cycle, content providers, for data sharing and management between apps, telephony manager for voice call management, location manager for the provision of Global Positioning System (GPS) services, and resource manager for managing resources used by applications. Applications are the top layer with most of them pre-installed by default. Most importantly, Android OS is a good example of an embedded OS, a multi-user OS and inbuilt with multi-tasking capabilities, but does not work in real-time (John, 2015). Code complexity Compared to all operating systems discussed in this paper, Android’s source code is less complex, hence debugging it is easier, and the chances of being hacked are very minimal. In this regard, Android is very secure and suitable to run mobile phones and tablets. Summary and Conclusion Technology has led to the development of robust operating systems with a graphical user interface for easier user interaction with computer devices. This paper focused on providing insights into various operating systems in terms of their structure, components, their working mechanisms, and whether their source codes are complex or simple. Being an academic study, the researcher only concentrated on three standard operating systems, namely, Windows, Linux and Android operating systems. As analyzed above, all the three OS are inbuilt with multi-tasking capabilities and are embedded. Windows operate in a single user mode. Android and Linux are multi-user, but only Linux can perform in real-time though it is not a real-time OS. As compared to Windows, Android and Linux are more secure since their source codes are less complex, implying that they are easier to debug in case a bug manages to sneak into them during or after coding. References Case Study 2: Windows 2000. (2015). Retrieved April 24, 2015, from Lovingod.host.sk: http://lovingod.host.sk/tanenbaum/Windows.html Linux® As a Real-Time Operating System. (2015). Retrieved April 24, 2015, from Freescale Semiconductor: http://www.freescale.com/files/soft_dev_tools/doc/white_paper/CWLNXRTOSWP.pdf Multitasking. (2015). Retrieved April 24, 2015, from windows: https://msdn.microsoft.com/en-us/library/windows/desktop/ms684259(v=vs.85).aspx The structure of a Linux Based Operating System. (2015). Retrieved April 24, 2015, from learnlinux.org.za: http://www.learnlinux.org.za/courses/build/fundamentals/ch04s02.html Windows embedded. (2015). Retrieved April 24, 2015, from Microsoft: http://www.microsoft.com/windowsembedded/en-us/products-solutions-overview.aspx John, S. P. (2015, February 3). Android Architecture. Retrieved April 24, 2015, from Eazytutz: http://www.eazytutz.com/android/android-architecture/ KING, R., & BOULTON, C. (2015, March 16). Complex, Legacy Code Creates Security Headaches for Microsoft Users. The Wall Street Journal. Mencken, H. L. (2015). History of Operating Systems. Retrieved April 23, 2015, from Kent State University: http://www.personal.kent.edu/~rmuhamma/OpSystems/Myos/osHistory.htm Perrin, C. (2010, February 1). The danger of complexity: More code, more bugs. Retrieved April 24, 2015, from TechRepublic: http://www.techrepublic.com/blog/it-security/the-danger-of-complexity-more-code-more-bugs/ Stallings, W. (2005). Operating Systems: Internals and Design Principles. New Jersey: Prentice Hall. Read More