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Operating System Articles
Page 153 of 171
Mac OS X Structure
The Mac OS is a graphical operating system developed by Apple Inc. The tenth version of the Mac OS is the Mac OS X which was launched in 2001.The structure of the Mac OS X includes multiple layers. The base layer is Darwin which is the Unix core of the system. Next layer is the graphics system which contains Quartz, OpenGL and QuickTime. Then is the application layer which has four components, namely Classic, Carbon, Cocoa and Java. The top layer is Aqua, which is the user interface.A diagram that demonstrates the structure of Mac OS X is as follows ...
Read MoreGoogle Android Architecture
Android is an operating system developed by Google for mobile systems. It is based on the Linux kernel and mainly designed for touchscreen devices such as tablets and smartphones.The Android architecture is divided into four main layers and five sections. This is explained using the given diagram −The details about the different parts of the Android architecture are given as follows −ApplicationsThe android applications are in the top layer of the architecture. They are mainly written in Java and run within individual instances of the Dalvik virtual machine. The main features of the Android applications should be performance and efficiency, ...
Read MoreApple iOS Architecture
The iOS is the operating system created by Apple Inc. for mobile devices. The iOS is used in many of the mobile devices for apple such as iPhone, iPod, iPad etc. The iOS is used a lot and only lags behind Android in terms of popularity.The iOS architecture is layered. It contains an intermediate layer between the applications and the hardware so they do not communicate directly. The lower layers in iOS provide the basic services and the higher layers provide the user interface and sophisticated graphics.The layered architecture of iOS is given as follows −Layers in iOS ArchitectureThe different ...
Read MoreMajor Activities of an Operating System with Regard to Process Management
A process is an active program i.e a program that is under execution. It contains the program code, program counter, process stack, registers etc. Process Management deals with processes and the various mechanisms to handle them.The various activities that the operating system performs with regard to process management are mainly process scheduling and context switching. Details about these are given as follows −Process SchedulingThere are many scheduling queues that are used to handle processes. When the processes enter the system, they are put into the job queue. The processes that are ready to execute in the main memory are kept ...
Read MoreMS-DOS Layered Structure
MS-DOS is an operating system created for personal computers. It was developed by Microsoft. It is a classic example of an operating system with a layered structure. MS-DOS operating system is split into various layers and each of the layers have different functionalities.Layering provides a distinct advantage in the MS-DOS operating system because all the layers can be defined separately and interact with each other as required. Also, it is easier to create, maintain and update the system if it is done in the form of layers. Change in one layer specification does not affect the rest of the layers. ...
Read MoreMajor Activities of an Operating System with Regard to Memory Management
Memory management plays an important part in the operating system. It deals with memory and the moving of processes from disk to primary memory for execution and back again.Some activities of an operating system with regards to memory management are −Memory AllocationA simple way to allocate memory is to provide the empty memory spaces to incoming processes as required. This can be done using the following algorithms −First-FitThe first available memory space that is large enough for the process purposes is allocated. Searching can start at the beginning or at the point where the last first-fit search ended.Best-FitThe smallest memory ...
Read MoreOperating System Design Goals
Operating Systems have become quite complex and multifaceted with the advancement of time. However, that also means it is getting more and more difficult to design operating systems that satisfy all the specifications required these days. There are no complete solutions possible for design problems, but some approaches are more successful than others.Design Requirements in Operating SystemThe design requirements are quite hard to specify in an operating system. They are basically divided into two parts: User design requirements and System design requirements. Details about these are given as follows −User Design RequirementsThe operating system should be convenient, easy to use, ...
Read MoreArchitecture of a Typical Microkernel
A microkernel is the minimum software that is required to correctly implement an operating system. This includes memory, process scheduling mechanisms and basic inter-process communication.A diagram that demonstrates the architecture of a microkernel is as follows −In the above diagram, the microkernel contains basic requirements such as memory, process scheduling mechanisms and basic interprocess communication. The only software executing at the privileged level i.e. kernel mode is the microkernel. The other functions of the operating system are removed from the kernel mode and run in the user mode. These functions may be device drivers, file servers, application interprocess communication etc.The ...
Read MoreMonolithic System Architecture
The entire operating system works in the kernel space in the monolithic system. This increases the size of the kernel as well as the operating system. This is different than the microkernel system where the minimum software that is required to correctly implement an operating system is kept in the kernel.A diagram that demonstrates the architecture of a monolithic system is as follows −The kernel provides various services such as memory management, file management, process scheduling etc. using function calls. This makes the execution of the operating system quite fast as the services are implemented under the same address space.Differences ...
Read MoreApplication Programs vs System Programs
There are mainly two categories of programs i.e. application programs and system programs. A diagram that demonstrates their place in the logical computer hierarchy is as follows −Application ProgramsThese programs perform a particular function directly for the users. Some of the common application programs include Email, web browsers, gaming software, word processors, graphics software, media player etc.All of these programs provide an application to the end users, so they are known as application programs. For example: a web browser is used to find information while a gaming software is used to play games.The requests for service and application communication systems ...
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