What Is The Role Of Middleware

Published Date: 02 Nov 2017

Middleware is the software that gives the features and usability that is not offered by the operating system itself. It makes easier to work on a specific task, which cannot be achieved by using only the operating system and its features.

Middleware is used for communication and the management of data in distributed applications.

Middleware in Distributed Applications:

Distributed system consists of number of computers or devices connected on a network. The middleware acts as the communication medium for a distributed system. It makes the access easy by altering the fact that there are number of systems on a network on different locations and maintains the constant standard throughout the system. The development of application is much easier as the middleware is providing common features of programming and hiding the presence and distribution of other hardware and operating systems, showing them all as a one unit.

(b)

What is an open distributed system and what benefits does openness provides?

Open System:

Open system is one which allows different systems and organizations to work together, adapt some software so a different program can be created from the one that is usually being offered and has unrestricted access by the public of a same genre.

Benefits of Openness in Distributed system:

It supports the different distributed applications by each host.

There is a level of independence between the systems (or hosts) and the underlying applications.

Any programmer on the network can provide different virtual devices according to the needs of the relevant applications.

If a machine is crashed, the data can still survive on the backup i.e. on other devices on the network.

An open distributed system can posses more power than the mainframe.

It is readily available to communicate.

It scales means it has an advantage over systems that are closed.

It is more economical.

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(c)

(d)

What do you mean by scalability? Explain any 3 ways through which scalability can be achieved.

Scalability:

Scalability is the ability to handle the growth of work and increasing the capability to deal with this growth. It refers to the electronics; let it be hardware or software. A system’s performance can be enhanced by adding a hardware or software; such a system is known as scalable system.

(e)

Ways through which scalability can be achieved:

Systems are made more productive to accommodate the highest expected usage. Few examples of system scalability are given below.

The up gradation of the computer system from by 32-bit architecture to the 64-bit architecture is the common way of scalability. Memory requirements are higher for the intensive applications like Computer-aided-design, high performance servers, database management etc. The 64-bit doubles the rate of process for input as well as output.

(f)

Online transaction system can be upgraded to tackle with more transactions or inquiry in a given time by simply adding more processors and storage devices. It can be done easily without the need to turn off the system. It is yet another way to scale a system.

(g)

Peer-to-peer systems scale well when the each peer is merely independent of the total number of peers available on the network at a time. The system expands without the need of addition of other devices for enhancement.

(h)

Explain why distributed systems are more measured than centralized systems. What are limits of scalability of the system?

In a centralized system, connections are made through one or more hubs. System is relied upon few central components making it difficult to detect or rectify the system if the hubs are put out of operation. The server’s limited capacity makes it difficult to scale the system while in the distributed system, the more hosts are added the more productive, the system is. The different devices on the network make it easier to scale a system on different levels and points, without shutting down the whole system. The smaller additions on different locations of the system contribute to the bigger advantage for whole of the system.

The limits to the scalability often create a little problem. Algorithms play a key role to maintain the distributed system. They assure the constancy to the overall system and in doing so; they carry a lot of overhead. When the overhead enlarges, the system doesn’t scale well resulting in the non-scalability. A system’s output is not achieved means the system did not scale.

(i)

Explain two-tier and three-tier architecture for distributed systems.

Two-Tier Architecture:

Two-Tier Architecture is one-on-one basis structure includes only a source and the client.

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The maintenance and the understanding of such a system is easier but it gets slower when there are more users on the server.

Three-Tier Architecture:

Three-tier architecture has three layers or say, a middle tier between the server and the client. The intermediate layer makes the processes faster between the server and the client, producing the higher output than the two-tier architecture.

The modification of such a system is easier as it doesn’t shutdown the other nodes; it processes the information exchange, faster with the higher performance.

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(k) (j)

References List:

(a) (Wikipedia, Wikipedia Organization, 2013)

(b) (Krakowiak, 2003)

(c) (Rahman, 2010)

(d) (Wikipedia, Wikipedia Organization, 2013)

(e) (Wikipedia, Wikipedia Organization, 2013)

(f) (Rouse, 2007)

(g) (Wikipedia, Wikipedia Organization, 2013)

(h) (Wikipedia, Wikipedia Organization, 2013)

(i) (Minar, 2002)

(j) (Palaniswamy, 2010)

(k) (Rothman, 2008)