Virtual Memory: Components, Application and Future Trends

This report discusses the components, application and future trends of virtual memory. It covers the main components of virtual memory, its application, and future trends in the field of information technology.

Running head: VIRTUAL MEMORY
Virtual Memory
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Table of Contents
Introduction to Virtual Memory.................................................................................................2
Components of Virtual Memory................................................................................................2
Application of Virtual Memory.................................................................................................4
Future trends in Virtual memory applications...........................................................................5
APA Citations............................................................................................................................5
Conclusion..................................................................................................................................6
References..................................................................................................................................7

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Introduction to Virtual Memory
The idea of creating logic space in the memory location of a machines is known as
virtual memory. The logical space in machines respectively corresponds to the physical
spaces located in the system (Vesely et al., 2016). The mapping of the logical spaces in to the
physical spaces are done by a process known as dynamic mapping. The virtual memory
stores the virtual or the logical addresses for the systems and provides the systems with the
virtual storage facility which helps them in the storing the temporary data in the system
logically and deleting the data when the requirement of the data is over. It also keeps the
process of the operating systems safe as they prevent a process to directly read or write the
contents of a particular process without prior permission from the system. The procedures of
the virtual memory arte done by a unit known as the memory management unit present in the
CPU of the system. This helps the system in maintaining a proper balance in the system and
provides efficient options for the operating system for the allocation and re-allocation of
memory to the process that requires it. This report consists further discussion of the
procedures and the components of the virtual memory.
Components of Virtual Memory
There are various components of the virtual memory among which the three are
notably the major elements of the virtual memory. These are Main Memory (RAM),
Secondary Memory (Disk) and the Page Table. The main memory holds the recent chucks of
the data in the system and secondary memory stores those chunks in the system. These are
those which are not currently being used by the system (Chi et al., 2016). The page table
holds the location of the data in the system. The most recently used data are stored in the
main memory. The pages are used for the storage of data and each of these pages are
subdivided into frames which stores the data after dividing them and allocating them to the

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respective blocks. The size of a frame is similar to that of a frame. The first frame always
indicates towards the address 0x00000000 to 0x00000FFF. The second frame always
indicates towards the address 0x00001000 to 0x00001FFF. In situation where the physical
memory is of 256 Mbs, the last addresses would basically range from the 0x0FFFF000 to
0x0FFFFFFF. The address range generally covers the 4096 bytes. Another important concept
to consider during the discussion of virtual memory is that of frame number. Basically the
first frame number is always indicated with a 0 and second frame has frame number 1 and so
on. The main memory can be considered basically as the fast storage and the pages that the
currently working with the system, overall can be easily considered as the storage system that
performs the function of a cache memory.
The disk memory is basically the storage system that helps in the storage of the pages
that are currently not required by the system. Whenever the system looks for a page the
appropriate page is brought from the secondary memory and transferred to the main memory
which would be performing the functions for the system. The addresses of the memory are
stored in the secondary memory (Wilkins et al., 2016). The processor generally fetches the
address from the main memory and is redirected to the secondary memory where it finds the
required addresses and the data in them and then again sends it to the main memory. In
addition to this, in case a page is modified the corresponding modification is also done in the
secondary memory of the system. The secondary storage can be thought of the as the long
term storage for the system.
The page table is used for keeping track of the pages of the systems and also the
properties of the pages are stored in the directories of the page table. The systems make an
update to the page table in case the system wants the page table alter and modifies the pages
and makes an update accordingly. In addition to the pages there are entries in to the pages for
the storage of data in the system and these entries are stored in the system into the virtual

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address space after being indexed. For the storage of the pages in the page table the 2n number
of entries are made so that n number of indexes are required in the page table.
Application of Virtual Memory
For the application of virtual memory is done generally in the entry of the page
numbers in the indexes of the page table (Seshadri et al., 2016). The component which is
being discussed in this area of the report is the page table. The virtual memory and the
physical memory are generally not required to have an extensive relation among themselves
although they work correspondingly with each other for the processor to process the data and
make changes accordingly. Hence, the bit operators are used for searching the addresses
required for the system and the operators would be indicating the requirement of the bits and
provide the location of the addresses in the virtual memory. The valid bits are used for the
indication whether the memory is available or not. It also provides a clear indication of
whether a memory has to be fetched from the secondary memory or it is already available in
the main memory. When the pages are fetched from the main memory the valid bit is set to 1
and in case the page is overwritten and the page is no longer required by the process the valid
bit is set to 0. In addition to this, there is the dirty bit, which indicates weather the memory
has been updated or the it has the same contents as of before. In case the memory has been
update and the update has been discarded the system must perform the write back operation
to take the memory into its previous state. In case the update the update has not been set to
the memory a dirty bit is set to 1 until the update to the main memory is done and the bit is
again set to 0 once the update is done. This helps a great deal in speeding up the system and
making efficient updates to the storage system of the machine. Whenever a page is loaded
into the memory the dirty bit of the page is set to 0. In case any type of write instruction is
performed on the system the dirty bit is set to 1.

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Access control is the process that is used for the protection of the memory in the
system. This helps in indicating the weather a user can read, write or delete a particular part
of memory in the system. This helps in preventing programs from harming the data of the
other and processes and the procedures of the data are not hampered by this. Additionally, the
frame number helps in helps in indicating about location of the frame in a particular page.
The disk location helps in determining the exact location of the data. In case the user wants to
the update of delete the data the user has to have knowledge of the disk location of the data in
system. In a sense quite similar to the frame number.
Future trends in Virtual memory applications
The concept of virtual memory has a huge development in the field of information
technology. There concepts of the virtualization and cloud computing has developed from
these concepts and there has been a huge improvement in these fields also (Mijumbi et al.,
2016). In the future the users would no longer require to store the data in the physical storage
systems of the personal machines. This is also expected to extend to the enterprises as well.
The cloud architecture developers have developed data centres which would be storing all the
important data required for the clients. This help in backup and recovery process of the data
for the clients.
APA Citations
How to change Virtual Memory Size in Windows 10 ... Retrieved from
http://mywindowshub.com/customization-virtual-memory-size-windows-10-
technical-preview/
If Windows virtual memory is too low, you can increase it ... Retrieved from
https://www.pcworld.com/article/2840886/if-windows-virtual-memory-is-too-low-
you-can-increase-it-but-there-are-trade-offs.html

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Johnson, B. Professional visual studio, 2015.
Operating System - Virtual Memory - Tutorials Point. Retrieved from
https://www.tutorialspoint.com/operating_system/os_virtual_memory.htm
Optimize Windows for better performance - Windows Help. Retrieved from
https://support.microsoft.com/en-us/help/15055/windows-7-optimize-windows-better-
performance
What is virtual memory? - Definition from WhatIs.com. Retrieved from
https://searchstorage.techtarget.com/definition/virtual-memory
Conclusion
For conclusion it can be said that the Virtual memory is one of the most efficient
concepts that has been developed over the years and this has helped a great deal in the
development of the process of the operating system in the machines of the users. It helps in
addressing a number of issues of a system and performs the process of memory management
and memory updating procedures. This paper has provided the description of the virtual
memory in the systems and components associated with it. Additionally, the description of
the page table component of the virtual memory has been discussed and future trends which
are associated with it.

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References
Chi, P., Li, S., Xu, C., Zhang, T., Zhao, J., Liu, Y., ... & Xie, Y. (2016, June). PRIME: a
novel processing-in-memory architecture for neural network computation in ReRAM-
based main memory. In ACM SIGARCH Computer Architecture News (Vol. 44, No.
3, pp. 27-39). IEEE Press.
Mijumbi, R., Serrat, J., Gorricho, J. L., Bouten, N., De Turck, F., & Boutaba, R. (2016).
Network function virtualization: State-of-the-art and research challenges. IEEE
Communications Surveys & Tutorials, 18(1), 236-262.
Seshadri, V., Pekhimenko, G., Ruwase, O., Mutlu, O., Gibbons, P. B., Kozuch, M. A., ... &
Chilimbi, T. (2016). Page overlays: An enhanced virtual memory framework to
enable fine-grained memory management. ACM SIGARCH Computer Architecture
News, 43(3), 79-91.
Vesely, J., Basu, A., Oskin, M., Loh, G. H., & Bhattacharjee, A. (2016, April). Observations
and opportunities in architecting shared virtual memory for heterogeneous systems. In
Performance Analysis of Systems and Software (ISPASS), 2016 IEEE International
Symposium on (pp. 161-171). IEEE.
Wilkins, V. V., Fallone, R. M., Meyer, A. T., & Boyle, W. B. (2016). U.S. Patent No.
9,268,499. Washington, DC: U.S. Patent and Trademark Office.