Windows Communication Foundation: Service Reliability is the Key

o far, this Windows Communication Foundation (WCF, formerly known as Indigo) series has provided a primer, and discussed security and transactions. The final pillar in the tripod that supports software-as-a-service is reliability, with which you can achieve the secure, transactable, and reliable services that WCF promises.

But what is reliability, and why is it so important? First, reliability is a key differentiating factor between software systems that cost millions of dollars to develop or own, and those that don't. Consider a financial scenario for portfolio management as an example. You have a number of assets at a brokerage; say 100 shares of Stock A and 10 shares of Stock B. You think stock B is likely to do well, but don't have enough funds to buy it. So you issue a command to sell your 100 shares of stock A, estimating that with the proceeds you will easily be able to afford 10 shares of stock B. But rather than wait for the transaction to complete, you also issue a command to buy 10 shares of stock B. Deals don't need to be realized for 3 days after the trade, so by the time you get the money for selling stock A you can afford stock B.