Comprehensive Report on Virtual Memory in Computer Architecture

This report provides a detailed examination of virtual memory, a crucial concept in computer architecture. It begins with an introduction explaining the role of virtual memory in enhancing computer performance by creating non-existent memory to supplement the need for more space. The report then explores key concepts such as memory swapping, the mapping between physical and virtual memory, and error handling. It delves into the applications of virtual memory, emphasizing how it enables the concurrent running of multiple applications and the sharing of available memory through paging. Furthermore, the report discusses current trends in virtual memory, particularly the development of FlashVM and flash-tier technologies. The report concludes by summarizing the importance of virtual memory in modern computing and its contribution to the development of smaller, more efficient storage devices. The report also includes a comprehensive list of references in APA format.

Virtual memory
Name
Institution
Professor
Course
Date
Executive summary
Virtual memory involves creating non-existed memory to supplement need for more space
required for efficient computer operations. This is usually created to serve as a cache between
hard disk and Read Access Memory (RAM). Virtual memory concepts are; memory swapping,
mapping between physical and virtual and error handling. Virtual memory helps to increase
computer performance as well as reduce programmable hardware size. Several trends in virtual
memory use has been implemented in FlashVM as well as flash-tier.

Contents
Executive summary................................................................................................................................1
Introduction..............................................................................................................................................1
Virtual memory concepts......................................................................................................................1
Application of virtual memory.............................................................................................................2
Virtual memory trends...........................................................................................................................3
Conclusion...............................................................................................................................................3
References...............................................................................................................................................4

Introduction
Virtual memory defines a type of hardware that allows system user to run many
applications irrespective of the physical memory available to support required operations. On
the same note, it has been described as simulated memory written into some files found on the
hard drive (Singh, Goyal & Kaur, 2014). In order for facilitate efficient working of the system, it
does simulation of the physical Read Access Memory (RAM) through implementation of
available hard disk space. In order to free up memory space that can be used by RAM to load
some other new applications, computers checks for unused RAM areas to copy them to hard
disk. With virtual memory, computer create another non-existed space to load applications by
making it work as if it has enough memory to load as many applications as possible. The main
idea behind virtual memory is to deduce more space from hard disk and use it as if it was
running on RAM. It is through virtual memory that computer application programming has been
made easier by eliminating all physical memory fragmentations (Yang, Berger, Kaplan & Moss,
2006). It is only through virtual memory that other applications are excluded from managing any
shared memory spaces in order to increase operational security through memory isolation.
Virtual memory concepts
It is through virtual memory in computer architecture that allows computer users run
many sophisticated programs irrespective of the amount of RAM installed in a specific
computer. Using virtual memory, computer jungles all demands of conflicting programs within a
fixed physical memory at any given time. For a computer to address all content in the RAM, it
must do so through use of system addresses (Sumant & Chawan, 2010). Important to note is
that, it is only through virtual memory that compatibility issue of software are eliminated. This is
eliminated by treating each software as if it was running on a different computer. It is the duty of
the operating system to make sure there are enough set of virtual addresses to support each
required application. In order to support these processes, Operating system translates all
available virtual addresses to physical ones dynamically. Similarly, the concept of file paging
supports virtual memory by writing program pages that have not been used in a hard disk. All
data is saved by the files and if an application program needs to use it again, the OS reloads it
again when RAM is available. At some instances, many programs might need to use RAM at
the same time. To manage this, page swapping is called to facilitate memory management
(Tripathy & Tripathy, 2014).

Additionally, virtual memory facilitates memory protection by preventing data from being
changed by another program running concurrently (Sumant & Chawan, 2010).It is obvious that
most of computer processes does not require all its running pages at once. The following are
some of the reasons that makes computer processes request different pages at different times.
First, some of the process pages such as error handling might not be required for the entire
period of running a process. Error handling are only called by processes once an error has been
encountered and if it does not occur, that specific space remains unused (Puaut & Hardy,
2007). Secondly, some of program features are rarely used and holding memory awaiting its
use results to waste of resources and computing power. Instead of holding memory while
awaiting its use by a sub-process that might not run for the entire life of the process, such
memory can be allocated to another demanding process.
Application of virtual memory
The use and importance of virtual memory cannot be underrated as it provides an
opportunity to all application programs to run concurrently on demand. It is quite impossible to
assume computers have enough memory to satisfy all running applications (Bairavasundaram,
Arpaci-Dusseau & Arpaci-Dusseau, 2006). At an instance, a computer runs many programs
which require each other or are in use by system user at the same time. Without virtual memory,
it would not be possible to have computers run faster as well as execute activities concurrently.
Through use of virtual memory, computers are able to share available memory to several
applications running at the same time. Sharing of available memory is usually done through a
process known as paging. Memory paging involves distributing a piece of memory to many
applications as possible. Operating system manages memory swapping in such a way that all
applications are running in a use and release concept.
Any running process may request to use a resource held by another process. A good
example can be deduced by having two processes, P1 and P2 sharing a common memory
(Lee, Bahn & Shin, 2014). If process P1 has been initiated by either user or a system, it may
request a resource in use by P2 or any other process. Depending on the nature of either
processes, P1 can wait or preempt resource from P2 only if P2 is able to release required
resource. If process P2 is non-preemptive, P1 might be forced to wait or get similar resource
from another process. The exchange of a piece of memory from one process to the other is
what facilitates running of many programs at the same time. According to Vaynberg & Shao
(2012), paging process happens within a very short period of time in such a way that system
user cannot realize if there is memory swapping. With memory swapping, computer is able to
2

sustain user’s need by running as many applications as possible. Lastly, by creating a buffer,
computer is able to execute process faster than if it was to fetch and move processes from RAM
and hard disk. Therefore, it would be worthy to conclude that, virtual memory concept has been
used to design almost all processes related to system resource maintenance.
Virtual memory trends
Virtual memory has resulted to development of new storage technologies which allows
system users interact easily with other devices. Development and use of flash disks has been
built entirely on virtual memory. The flash-tier works on basis of solid-state caching which is a
flash device with ability to interface with other systems through caching. The other observable
trend is on Flash meets virtual memory (FlashVM) which offers capability of developing flash
which uses virtual memory paging instead of using actual disks (Ji & Zeng, 2015). Through use
of virtual memory, it has been possible to increase flash performance, reduce the size of
hardware as well as make it possible to have efficient garbage collection. FlashVM offers more
than 94% of reduced execution time on application which is four times faster than disk
swapping.
Conclusion
Implementation of virtual memory provides an opportunity to computers to have faster
computers operations than before. Since it is impossible to have enough memory on computers,
the best aspect would be to focus on how to actualize on virtual memory usage. Leveraging on
virtual memory development would greatly help in coming up with small storage devices which
have high performance capability. Through use of virtual memory, it has been possible to
develop light weight and persistent memories such as SSD’s. Similarly, virtual memories helps
come up with small but scalable devices.
3

References
Bairavasundaram, L. N., Arpaci-Dusseau, A. C., & Arpaci-Dusseau, R. H. (2006). Dependability
analysis of virtual memory systems. In Dependable Systems and Networks, 2006. DSN
2006. International Conference on (pp. 355-364). IEEE.
Ji, X., & Zeng, F. (2015). Flash-aware Virtual Memory System for Consumer Electronics.
International Journal of Multimedia and Ubiquitous Engineering, 10(8), 329-338.
Lee, H., Bahn, H., & Shin, K. G. (2014). Page replacement for write references in NAND flash
based virtual memory systems. Journal of Computing Science and Engineering, 8(3),
157-172.
Puaut, I., & Hardy, D. (2007). Predictable paging in real-time systems: A compiler approach. In
Real-Time Systems, 2007. ECRTS'07. 19th Euromicro Conference on (pp. 169-178).
IEEE.
Singh, A., Goyal, G., & Kaur, J. (2014). Design of Swap Space in Virtual Memory management
System. International journal of Current Engineering and technology, 4(3), 1982-1985.
Sumant, A. S., & Chawan, P. M. (2010). Virtual Memory Management Techniques in 2.6 Kernel
and Challenges. International Journal of Engineering and Technology, 2(2), 157.
Tripathy, M., & Tripathy, C. R. (2014). A Comparative Analysis of Performance of Shared
Memory Cluster Computing Interconnection Systems. Journal of Computer Networks
and Communications, 2014.
Vaynberg, A., & Shao, Z. (2012). Compositional verification of a baby virtual memory manager.
In International Conference on Certified Programs and Proofs (pp. 143-159). Springer,
Berlin, Heidelberg.
Yang, T., Berger, E. D., Kaplan, S. F., & Moss, J. E. B. (2006). CRAMM: Virtual memory
support for garbage-collected applications. In Proceedings of the 7th symposium on
Operating systems design and implementation (pp. 103-116). USENIX Association.
4

5