My Tech World

Windows Communication Foundation - Basics

2012-09-21T16:56:00.000+05:30

I had a presentation on WCF (Windows Communcation Foundation) basics today in office. I walked through the basics mostly.

Here is the plan followed in the presentation.

Introduction
Service Oriented Applications (SOA)
Distributed Technologies - Evolution
Purpose of WCF
WCF Architecture
WCF - Bindings
WCF - Key classes in development

1. Introduction

Presented the different definitions from the authors about WCF. Following are the two definitions got from the authors.

"Windows Communication Foundation is a programming platform and runtime system for building, configuring and deploying network-distributed services."

"Windows Communication Foundation (WCF) is a framework for building service-oriented applications"

More details will be covered in later sections.

2. Service Oriented Applications (SOA)
Explained the definitions of "Service" and "SOA". Here are they...
Service:
a. work done by one person or group that benefits another

b. A Component capable of performing a task

These are the general definitions/meanings from the English dictionary. The same will be applied to the Services created in the software.

SOA: "A set of components which can be invoked, and whose interface descriptions can be published and discovered"

We can compare the services in the software with the following example.
"A Car decor company provides a set of services to the cars, he will expose his list of services through some ads, but will not show their internal process of work". Similarly, Service is a component which can be invoked and whose interface descriptions can be published.

The programming models were evolved from Procedural model to Object Oriented to Service oriented model today.

2.1. SOA and WCF

I have explained the four design principles of "SOA" which are known as "Four Tenents of Service Orientation".

a. Boundaries are explicit - Applications and services communicate by sending messages to each other. You should not make any assumptions about how a service processes a request or how a client application handles any response to a request. Following this principle can help to remove dependencies between services and client applications. Additionally, sending and receiving messages has an associated cost in terms of communications. You should design the operations that services implement with this in mind, and ensure that clients call services only when necessary.

b. Services are autonomous. If you are building an application based on services, you might not have control over every service you are using, especially Web services hosted outside of your organization. The location of a Web service might change, or a service might be temporarily taken off-line for maintenance or other reasons. You should design your solutions to be loosely coupled, so that they can tolerate these changes and continue running even if one or more services are unavailable.

c. Services share schemas and contracts, not classes or types. Services publish information about the operations that they implement and the structure of the data that they expect to send and receive. Clients use this information when communicating with the service. You should design contracts and schemas to define the interfaces that your services expose. This can reduce the dependencies that clients have on a particular version of your services. Services can change and evolve over time, and a new version of a service might appear superseding a previous version. If a service is updated, it should maintain compatibility with existing clients by continuing to implement existing contracts and send messages that conform to existing schemas. If you need to modify a service and provide additional functionality, you can add contracts and schemas that extend the original capabilities of the service while retaining the existing contracts and schemas. Older client applications should continue to work unchanged.

d. Compatibility is based on policy. The schemas and contracts exposed by a service define the “shape” of the service but not the nonfunctional requirements that a client attempting to access the service must fulfill. For example, a service might have security requirements that state that clients must connect to it in a particular manner and send and receive messages by encrypting data in a specific way. This is an example of policy.

WCF has been designed with these principles.

3. Distributed Technologies - Evolution
Explained about the evolution of the various distributed technologies over the time till now. Following are some of the distributed technologies used.

Pipes and Sockets - This is very low level mechanism and using it required a good understanding of how networks work.
Component Object Model (COM) - Microsoft developed COM as mechanism for communicating between applications and components running on the Windows platform. Microsoft originally designed COM to enable communications between components and applications running on the same computer.
DCOM - COM was followed by Distributed COM, enabling the applications running on other computers over the network.
.Net Remoting
Enterprise Services
COM+ - COM was combined with the Microsoft Transactions server.
MSMQ
Web Services
Web Services Enhancements (WSE)

4. Purpose of WCF?

The purpose of WCF is to provide a unified programming model for many of these technologies, enabling you to build applications that are as independent as possible from the underlying mechanism being used to connect services and applications together

WCF does not replace any particular technology, but it provides uniform platform to use many technologies like web services, MSMQ, windows services etc.

5. WCF - Architecture

WCF services typically deals with the concept called "EndPoint". End point is the combination of ABC.

A - Address (where is the service deployed?)

B - Binding (How can the service be used?). Various bindings available explained in later section.

C - Contract (What does service provide?)

Following is the architecture of WCF

6. WCF - Bindings

Explained the partial list of bindings available for WCF and their respective properties.

7. WCF - Key classes
We have four main classes to be used in WCF service development. All these classes are available in the namespace System.ServiceModel.

ServiceContractAttribute - This is used to decorate the interface which will be exposed from the service.
OperationContractAttribute - This is used to decorate the methods/operations of the interface.
DataContractAttribute - This is used to decorate the entity objects used in the service.
DataMemberAttribute - This is used to decorate the properties of the entity objects in the service

In my next post, will explain WCF with examples. Hope the basics of WCF help someone...

Thank you,

Raheem MA

The Twelve Attributes of a Truly Great Place to Work

2011-09-22T12:56:00.000+05:30

Tony Schwartz

Tony Schwartz is the president and CEO of The Energy Project and the author of Be Excellent at Anything. Become a fan of The Energy Project on Facebook and connect with Tony at Twitter.com/TonySchwartz and Twitter.com/Energy_Project.

More than 100 studies have now found that the most engaged employees — those who report they're fully invested in their jobs and committed to their employers — are significantly more productive, drive higher customer satisfaction and outperform those who are less engaged.
But only 20 per cent of employees around the world report that they're fully engaged at work.

It's a disconnect that serves no one well. So what's the solution? Where is the win-win for employers and employees?
The answer is that great employers must shift the focus from trying to get more out of people, to investing more in them by addressing their four core needs — physical, emotional, mental and spiritual — so they're freed, fueled and inspired to bring the best of themselves to work every day.

It's common sense. Fuel people on a diet that lacks essential nutrients and it's no surprise that they'll end up undernourished, disengaged and unable to perform at their best.
Our first need is enough money to live decently, but even at that, we cannot live by bread alone.
Think for a moment about what would make you feel most excited to get to work in the morning, and most loyal to your employer. The sort of company I have in mind would:

Commit to paying every employee a living wage. To see examples of how much that is, depending on where you live, go to this site. Many companies do not meet that standard for many of their jobs. It's nothing short of obscene to pay a CEO millions of dollars a year while paying any employee a sum for full time work that falls below the poverty line.
Give all employees a stake in the company's success, in the form of profit sharing, or stock options, or bonuses tied to performance. If the company does well, all employees should share in the success, in meaningful ways.
Design working environments that are safe, comfortable and appealing to work in. In offices, include a range of physical spaces that allow for privacy, collaboration, and simply hanging out.
Provide healthy, high quality food, at the lowest possible prices, including in vending machines.
Create places for employees to rest and renew during the course of the working day and encourage them to take intermittent breaks. Ideally, leaders would permit afternoon naps, which fuel higher productivity in the several hours that follow.
Offer a well equipped gym and other facilities that encourage employees to move physically and stay fit. Provide incentives for employees to use the facilities, including during the work day as a source of renewal.
Define clear and specific expectations for what success looks like in any given job. Then, treat employees as adults by giving them as much autonomy as possible to choose when they work, where they do their work, and how best to get it accomplished.
Institute two-way performance reviews, so that employees not only receive regular feedback about how they're doing, in ways that support their growth, but are also given the opportunity to provide feedback to their supervisors, anonymously if they so choose, to avoid recrimination.
Hold leaders and managers accountable for treating all employees with respect and care, all of the time, and encourage them to regularly recognize those they supervise for the positive contributions they make.
Create policies that encourage employees to set aside time to focus without interruption on their most important priorities, including long-term projects and more strategic and creative thinking. Ideally, give them a designated amount of time to pursue projects they're especially passionate about and which have the potential to add value to the company.
Provide employees with ongoing opportunities and incentives to learn, develop and grow, both in establishing new job-specific hard skills, as well as softer skills that serve them well as individuals, and as managers and leaders.
Stand for something beyond simply increasing profits. Create products or provide services or serve causes that clearly add value in the world, making it possible for employees to derive a sense of meaning from their work, and to feel good about the companies for which they work.

In more than a decade of working with Fortune 500 companies, I've yet to come across a company that meets the full range of their people's needs in all the ways I've described above. The one that comes closest is Google. I'm convinced it's a key to their success.
How does your company measure up? What's the impact on your performance? Which needs would your company have to meet for you to be more fully engaged?
Editor's Note: If you've just discovered Tony Schwartz and want to read more, start here: "The Only Way to Get Important Things Done."

Courtesy by - http://blogs.hbr.org

Medline Plus

2011-09-21T22:34:00.000+05:30

The following site is very informative, whichever diseases you click upon, it gives the video explanation. Interactive site on Medical Information.

http://www.nlm.nih.gov/medlineplus/

Hope this will be helpful for all!!!