Virtual Memory With Paging And Virtual Memory Computer Science Essay

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As Introduction, Operating System plays an important role as a software which can control computers and provides certain services for computer programs. The Operating System ability is managing all memory, process and also computers. Operating System is like similar to General Manager where it takes care everything but in OS way, it handles file management, devices, networking and also the security of the computers.

The question is about the Operating System which available in today's market. User are required to collect and analyse all information about Operating System in market which are available and compare with the other Operating System. In the World today, Operating system is not limited to computers but also available in mobile devices.

Question 1

The Operating System is capable to provide all kind of utilities and services for the management to the users. In the previous Operating System when in testing phase, it only has one disadvantage which is unable to multitask so it can only process one at a time but compare today technology Operating System can Multitask which make use easier to use it and also it takes a shorter period to complete a task given by the user.

As the information gather by the user, today's market, there are a lot of various kind of Operating System sold to every user in the world. The types of Operating Sold is Microsoft Windows, Mac OS, Linux, Android and also IOS.

A person by the name of Bill Gates, he's the owner of the Microsoft Corporation. Microsoft Corporation create Window as an Operating System which is well known to all user throughout the world. Through their spec and performance, Microsoft Windows is famous in the world. In the Market, Window XP, Window 7 and Window 8 are available.


A person by the name of Steve Jobb, he's the owner of the company of Apple Inc. Apple Inc is pretty well known in International Corporation. Apple Inc. has created all kind of devices such as Mac (Macintosh), IPhone, IPod and also IPad. Apple Inc. also created an Operating System by the name of iOS. Diagram below shows, the product release since 1984.


Linux is an operating system where it's free to use to all users. It is the software on a computer that enables applications and the computer operator to access the devices on the computer to perform desired functions. The operating system (OS) relays instructions from an application to, for instance, the computer's processor. The processor performs the instructed task, then sends the results back to the application via the operating system.


This are the three major Operating System available on Today's Market. Three of the major Operating are going to compare by their Security, Connectivity, Performance and also Software Capability.

First, Security Wise. Based on Three Operating System, Linux and Mac OS can provide a highly secured against any threat of malicious attacks but Windows unable provide the same. It is because that window has low secure in security wise and moreover, it was been targeted by malicious targets. Fortunately, with the new release of windows such as window XP, window 7 and window 8 has improve the security level. So it can be trustable to use.

Connectivity of three Operating System, Window and OS was built with the principles of the networking and also compatible with all hardware devices but where else OS only uses network devices which is produce by Apple only. Linux has no problem because it's almost similar to Windows.

In Performance Wise, All three Operating System has Graphical User Interface (GUI), so they are able to provide users an easy environment to interact with computer and data. Linux OS only requirement a minimum of hardware to achieve the fully functional level to all computers. Where else, Mac OS offers such a clean and friendly environment to make the user interact with the application friendly and require very less curve on the hardware. As for Windows, provide a such a user friendly environment where it has a indexed search menu such as the start menu, so it make a the search swiftly.

Lastly, The software comparability on three of Operating System. In Today worlds, Software in Operating System is a big issue when a user's purchases a new computer or an upgrade, as in the market rating shows Windows is standing in the first place because Windows is able to support every games with the maximum of 64bits. Where else, Mac OS is mostly use as for designing with Adobe Photoshop, Adobe dream viewer and Etc. Linux OS has few disadvantages when it comes to games as it doesn't have all the requirement in the OS.

Operating System not only handle with computers but also handle with handheld devices such as Computer Tablets and also smartphones. There two company who are enemy to each other are also available in the market. One is the Apple and another is Android, based on Linux OS and recommended by Google Inc.


Comparison between iOS and Android, iOS is only available on Apple Product such as IPhone, IPad and iPod. Android is only available in smartphone such as Samsung, Sony, HTC and Etc. Both also offer users to the application store and download various item to the product. Somehow, Android has the similar security problem with Windows where else iOS still maintain same as Apple.

Conclusion on Question 1

In Conclusion, This are the Operating System which are available in the market today. There are three kind of OS which is Linux, Windows and Mac. Three of the OS have been compare through Security Wise, Connection Wise, Performance Wise and also Software.

As the information Gather, Most of the user prefer Windows then Mac and Linux as Window has been supporting all kind of games. As for Mac, can be used in the office and Linux in the programming wise.

It's recommend that user to choose the suitable Operating System so that user won't feel any problem in the future.

Introduction on Question 2

Virtual memory is a part of memory management and it is also a feature of an operating system. It is a concept of virtual memory is such as while a single application is occups the physical memory of the computer system, the memory management unit (MMU) will emulate virtual memory for another application which wants to use the main memory and this process is a form of multitasking.

In the question, there are two type of virtual memory implementation, one is with the paging method and the second is the segmentation method. After collecting information on the two types, a comparison is made and their differences. In the end of the assignment, user requests to an explanation about the interrupt process.

Question 2

In Virtual Memory, Kernel is the main component in an operating system where it performs its task of memory management by having full control of the memory available in the system and allocates the memory required by the processes when they require it. This is accomplished by using virtual addressing and virtual address space.

Basically, Virtual Memory is an application that run on an operating system where the operating system creates a new process and a new virtual address space is created for this process. A user runs a process on 32-bit operating system and the possible virtual memory. Virtual addressing helps the kernel to make a virtual address appears as a physical address for the process which cannot occupy the main memory which will be already busy with an earlier process. This system makes multitasking processes becomes possible.

There are two ways of which are paging and segmentation:


Paging each process has its own page table. Each page table entry contains a present bit to indicate whether the page is in main memory or not. If it is in main memory, the entry contains the frame number of the corresponding page in main memory.If it is not in main memory, the entry may contain the address of that page on disk or the page number may be used to index another table (often in the PCB) to obtain the address of that page on disk. A modified bit indicates if the page has been altered since it was last loaded into main memoryIf no change has been made, the page does not have to be written to the disk when it needs to be swapped out. Other control bits may be present if protection is managed at the page level a read-only/read-write bit protection level bit, kernel page or user page.


Similarly to paging, each segment table entry contains a present bit and a modified bit. If the segment is in main memory, the entry contains the starting address and the length of that segment. Other control bits may be present if protection and sharing is managed at the segment level .Logical to physical address translation is similar to paging except that the offset is added to the starting address.

The interrupt process is a dynamic event that needs permission from the CPU. Basically, an interrupt only needs a short period of CPU time to serve it. After that, the continues back with it process. There are two types interrupting process which are Hardware Interrupts which are those issued by Input/output devices when they need CPU to process Input/output data, and software interrupts, also called traps, that are raised when the current process executes a special trap instruction to indicate that something wrong has happened in somewhere or the process needs special service from the operating system. Only a limited number of types of interrupts are defined. For each type of I/O devices, there is a special program called an Interrupt Handler to serve the interrupt requests from these devices. Each type of interrupt has an associated Priority Level where a running process would only be interrupted by an interrupt source or trap of higher priority. When the CPU is executing an interrupt handler, the interrupt handler may be further interrupted by an interrupt source of even higher priority.

Conclusion on Question 2

In Conclusion, Virtual management has two type of method which are paging and segmentation. Both method also taking care of memory but in a different ways. Paging uses maximum memory where else the segmentation used less memory where it become a wasted.

As for Interrupt Process, it has 4 types of interrupt. Each interrupt consists it reasons. Moreover, it is important process where the Operating System able to multitask each interrupts