问题
I am trying to undestand "What really SAAS is". It is Software as a Service, and hotmail outlook is one example of SAAS. But I am still in confusion. Suppose, I built an web app "Hospital Management System" which keeps the record of all patient and all that, Is it a Software as a Service. What specific things are needed to be a Software as a Service, or just a web app is a SAAS????
回答1:
A software is SAAS if it is deployed and managed to serve mutiple users (tenant is the term here) from the same deployment. That means the software is not deployed at the client side and it need not be one per tenant.
Your Hospital Management Systems would be a SAAS if you deployed it in your infrastructure and multiple hospitals used them as if you had created one for each of them.
Here are a few links that will help to understand better.
Databse architecture (single db vs client specific db) for Building Enterprise Web (RIA) application on cloud
Explanation of Tenant Load Balancer in SaaS maturity model level 4
回答2:
Web applications (especially online and browser-based application services) require a significant amount of flexibility to accommodate ever-changing user demand. SoftLayer’s infrastructure lets you customize highly scalable solutions ideal for meeting today’s needs without compromising cost efficiency or expansion speed. Linear stacks of Web, application and database servers can be added on the fly to precisely meet demand whenever more resources are needed.
来源：https://stackoverflow.com/questions/16121025/web-application-saas