Virtualization of Ubiquitous System Using Distributed Shared Memory

KEYWORDS—mirroring; virtualization, redundancy, Server_response, Client_request

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1.     INTRODUCTION

Distributed shared memory system is a resource management component of a distributed operating system that can be implemented the shared memory model in distributed system, which has no physically memory.

DSM is just a form of memory architecture where physically separated memories can be addressed as one logically shared address space.

Now the term “shared” does not defined that there is a single centralized memory but that the address space is still “shared”.

A distributed memory system called as multicomputer, contains multiple independent processing nodes with local memory modules and these are connected by a general interconnection network.

In disk mirroring we can implement the concept of data/message passing with two different devices, while using this it can be helpful in saving the more money on hard disks or on any storage media

In DSM false sharing is major problem but as per the new algorithms it can be easily solvable, this can increase the CPU performance and loss of memory has been reduced

Data consistency problem occur in DSM on the other hand caching technique increases the more efficiency of the DSM system, consistency problem occurred when processor modifies the replicated shared data.

The mirroring concept is just a Redundant Arrays of Inexpensive Disks (RAID), in this mechanism files are “striped” across multiple disks.

RAID concepts divided by in many level, the mirroring is just on to the RAID: 1 level and shows the mirroring facts like bandwidth sacrifice on write i.e. Logical writes = Two physical writes, distributed concept can be optimizing this with the RAID concepts.

Proposed System Architecture

Figure 1 System Architecture

• Main Memory – File reader and writer Area that can hold overall value of Original Editor and replicated editor window
• Memory M1 – First Work area memory that can store values in separate memory address
• Memory M2 – Replicated window memory area
• Write operations – Text Editor Window that can demonstrate the distributed shared memory concepts

2.     DESIGN ISSUES

In Distributed Shared Memory there are several Design Issue that must be a concern before going to another part of DSM.

• Granularity:

Granularity denotes the size of the sharing unit or it can be any memory unit like byte, a page, a word any other type of unit. Picking the correct granularity is an issue in distributed shared memory since it arrangements to the measure of calculation done between synchronization or correspondence focuses. Moving around code and information in the systems includes inertness and overhead from system conventions. Hence, such remote memory gets to should be incorporated in some way or another with the memory administration at every node. This regularly compels the granularity of access to be a vital different of the principal unit of memory administration or essentially exchange some portion of the page for decreasing the inertness

• Virtual memory and distributed shared memory:

Virtual Memory concept in modern computer system gives us a very high-performance computation power. Virtual Memory system is responsible for page replacement, flushing, and swapping. Satisfying a remote memory request, the distributed shared memory would have to refer to virtual memory manager to catch a page frame. The efficiency of the distributed shared memory model depends critically on how fast a remote memory access request is examined and the computation can be acceptable to continue.

• Memory Model and Coherence Protocols:

To assurance the correct multiprocessor execution, memory models should be working with precaution. Sequential Consistency memory model assurance that the view of the memory is stable at all times from all the processors, Release consistency which separates between kinds of synchronization accesses, acquire, release starting a stable view of the shared memory at release point.

3.     PARALLEL COMPUTING

Computers aren’t able to possess with the scale of data becoming available in today’s generation, like for genetic data set computers become slow to cope up with the scale of processing problems, still the computers themselves are getting faster.

Another solution for this is “multiple processors”, If multiple processors are available then several programs can be executed rapidly. While one processor is doing one part of some calculation, others can work on another part of the same system. Every one of them can have similar information, yet the work will continue in parallel.

So as to have the capacity to cooperate, various processors should have the capacity to impart data to each other. This is able to done via using a shared-memory environment.

4.     DISTRIBUTED SHARED -VIRTUAL MEMORY ARCHITECTURE

Many investigators have studied the issues in using operating system’s virtual memory as a cache, purpose to management systems of virtual memory based architecture system. In this method, the database can directly map into virtual memory to use determined objects as transitory of memory objects.

The next subsection, there are some protocol that shows the working mechanism of virtual memory based protocols

• DSM Client Protocol

In this protocol, file can be share as per the client side node protocol mechanism to share the same memory space where client and their respective processor unit, a memory unit, connection variable and all necessary component of sharing memory are working together to act as one unit make a virtual space area for all their components.

The client sends a request to the server to process the receive or make_connection command in order to execute the client request after execution of client process client can able to share the same virtual memory area in the connection-oriented model.

• DSM Server Protocol

DSM Server Protocol initiates the connection between the server and respective client, after successful connection the DSM server receive a request from the client side to process client’s request I order to provide the execution of process components.

Server sense for the request in the network (wired or wireless) if any request is in execution in the network then server contact to DSM server component after that Distributed Shared memory area is ready to use by DSM client components.

5.     BASIC ALGORITHM

There are some basic algorithms in DSM that demonstrate the working of DSM.

• The central-Server Algorithm

In this algorithm, the main central server is responsible for maintaining all of the shared data in the context of DSM environment, for the rad and write server has to be just return or update the data.

• The migration algorithm

Data is sent to the location of the data access request and the successive accesses are local, for both the read and write operation send back the remote page to the local system location. In this system, multiple reads can be more costly to the worth of processor that is used to done this job.

• The Read-Replication Algorithm

On the read operation the page is replicated and respective write operation except for one copy all copies are updated with the current timestamp approach. Allowing multiple readers to the same page and there is multiple reads, one write.

• The Full Replication Algorithm

Full Replication allows us to use the multiple reads and multiple write operation at the same time in DSM.

While in the full replication mode this algorithm can be controlled to the permit of Shared Memory.

6.     APPLICATION SCENARIO

In this section, there is an application scenario of using the virtualized Operating Systems on server-side virtualization.

A client can utilize different occurrences of virtualized Operating Systems to arrange situations to confine untrusted applications and to hold them in particular virtualized Operating Systems.

Such distinct Virtualized Operating Systems can be linked with partially CPU resources by using resource management tools.

The following main task is a process in this algorithm:-

• The user can use the multiple processes on Virtual Operating System to utilize the virtual memory for the reusable purpose.
• This system shows a virtualized OS environment that can separate resource management from each other.
• In this application the share of the CPU resource used by an entire virtualized OS environment that can be kept and also restricted in order to make an isolated implementation environment

7.     DESIGN

The whole paper is containing three modules: –

• Module 1- Customized  Proposed Architecture

We make a hybrid system that can perform multiple functionalities over the same memory area and can be created replicate text window to write on it and simultaneously user can send the created file to the server memory area and call the network function to establish the connection between them.

• Module 2- Load managing in communication channel

While creating the respective document file in Application environment, there is no need to always to connected to the communication channel because if there is N number user then they will make more burden on network channel, in case of reducing this in this application user have choice to connect to the network or else user can be disconnected from network channel.

• Module 3- Final working Environment

In the last working model we implemented the last final model of the application with all functionality like TextEditor functioning and as well as Server client concept that can share the same memory space and the same network area to communicate, the virtual memory concept will also take place in this application.

8.     CONCLUSION

This application is based on the concept of window mirroring, DSM and provides the replica of same workspace in multiple windows, apart from that user can also be share the same file on which he is working to the server portal or we can say that server can control multiple users working space and can edit the file or send back to client’s local space.

In Real-time file sharing and modification can be done using the socket programming tools and networking protocols.

Virtual Memory for the server side is light weighted as per the load balancing and other concepts shows the real working prototype of this application system

The objective of proposed system is to reduce the network traffic as much as possible leading to more effective and efficient DSM system than most other systems.