Free Essay - Virtual Memory

Virtual memory is a vital part of desktop computers for most operating systems. Its popularity is because of the vast advantage it accompanies itself with for its consumers. Most of the networks in the world either consist of a 32 or a 64-megabyte of RAM. The RAM is used by the CPU to run programs; unfortunately, the amount that these computers have is not enough to complete all the tasks. The importance of virtual memory is that it incorporates each process with its own space of an address, reusable in each process (Bhattacharjee, 2017).

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Tutorials comparison

Virtual addresses get mapped by the virtual memory directed to physical addresses. The mapping gets done with the help of the hardware and software available on a machine. The first tutorial is from Tutorialspoint, where they explain the differences cache memory has to virtual memory. The tutorial identifies the two memories defining virtual memory as one that is more of a technique used to hasten the actual memory rather than just a type of memory. The tutorial goes further to explain that the OS is mandated to manage virtual memory. The second tutorial is from W3schools.in, whereby the tutorial is the point on what virtual memory is and what it adds to a machine. The tutorial defines virtual memory as a conceptual technique that makes process execution happen that are generally not found in mind.

The W3schools.in tutorial goes more in-depth to give the uses of virtual memory, one being that it allows file sharing for processes effortlessly. Besides for process creation, it offers a critically better-organized mechanism for the procedure. I prefer the tutorial, and I have derived all the research based on the W3schools, in the tutorial. It is well organized as well as information on what virtual memory is and what it does.

How Virtual Memory Extends Available Applications

The operating system controls the virtual addresses space and the optimization of assigning memory that is real to virtual memory. Virtual addresses get translated by the memory management unit found in the CPU hardware. To provide a virtual address operating systems software may lengthen the proficiency, which then has an effect of referencing memory apart from the one present in the computer psychically (Bhattacharjee, 2017).

Virtual memory is beneficial as it frees up applications from having the issue to manage memory spaces that get shared. Besides, it also hastens security, which is possible due to the isolation of memory and the ability to utilize memory besides the one physically available, which is only possible by the method known as paging.

Drawbacks of a Page Fault

A paging fault is brought about by an attempt by a program to obtain information that is not accessible in the RAMs system but is available in its spaces address. Main memory can complete a process provided that the virtual memory address is resident in physical memory. Furthermore, MMU signals a page fault exception given an instance where the virtual memory is note resident making a need for the CPU to divert implementation to codes that are specially called a page fault. When a page fault occurs, the program counter gets saved on the stack as the hardware computer traps to the kernel. Secondly, to salvage the general registers, the program assembly gets commenced; besides, it also aids the OS from destroying volatile information (Bhattacharjee, 2017).

Thirdly the OS identifies the page fault and determines the type of virtual page that is required. The system also checks to determine the validity of addresses and also determines whether there are no access program protections once the page address fault gets discovered. If, for instance, the virtual address gets verified, the OS receives mandated to determine the page frame's availability. Algorithms get replaced, given the fact that no frames are free to do away with a page.

Page tables get updated as soon as the disk interrupt indicates the arrival of the page, and a healthy state gets marked. The PC receives rest when faulting instructions get backed up to its original state, with the OS reverting to the same process that initially called it. Lastly, the register gets reloaded by the assembly routine, and to continue with execution, other state information reverts to their user space (Bhattacharjee, 2017). .

Benefits of Virtual Memory

There are numerous advantages of virtual memory firstly it aids in the gaining of the speed of programs to be executed. Secondly, for multiprogramming, it comes quite an in hand. It also makes running of numerous applications smooth at once. It also helps one to fit into smaller programs many large ones. It also comes with the advantage of sharing between memories common data or codes.

Conclusion

One point about virtual memory that got my attention is that when used, it tends to slow down computers for the mapping of data in physical memory and virtual. The mapping requires more support from the hardware for translation of the addressed. In its advantages, virtual memory does it aids in the gaining of the speed of programs to be executed with also making the smooth running of numerous applications possible. To grasp the idea behind all that are vividly utilizing the resources at hand to master all the areas that had issues in clearly defining virtual memory.

References

Bhattacharjee, A (2017). Architectural and Operating System Support for Virtual Memory. Morgan & Claypool Publishers. p. 1. ISBN 9781627056021. Retrieved October 16, 2017