LECTURE 4

Platform-as-a-Service, or PaaS : 

Platform as a service (PaaS) is a category of cloud computing services that provides a platform allowing customers to develop, run and manage generally  Web applications without the complexity of building and maintaining the infrastructure typically associated with developing and launching an app.

Even most non-techies probably have an idea of what cloud computing is by now, but when you start getting into IaaS vs. SaaS vs. PaaS even those of us in the industry can struggle. In a nutshell, infrastructure as a service (IaaS) provides virtual machines or storage from a provider on demand with elastic scalability and software as a service (SaaS) simply involves hosting software in the cloud (like Salesforce.com) so it doesn't take up on-premises resources. But what about platform as a service (PaaS)? What exactly is it, for most people, the term "cloud platform" is even fuzzier than cloud computing as a whole.

so before we move on Let’s start with a simplistic understanding of the term “platform” first for computing, and then we will expand our definition to the realm of cloud computing. 

A platform generally refers to“prefab” software architecture upon which you can build computing solutions. It provides core software functionality, which would otherwise need to be engineered from the ground up. Can you imagine building an oven every time you wanted to cook dinner?  Probably not. Fortunately, the oven is already built; otherwise your meals would cost $500 each. Likewise, the cloud needs platforms to do a lot of the grunt work, which otherwise needs to be engineered into every software application from the ground up at great expense.

Cloud platforms serve as a launch pad for cloud software, providing “prefab” functionality such as a user interface, user sign up and administration, role-based security, federated search, multi-tenant data management and so on.

NOW WHAT "PLATFORM"- “AS A SERVICE”: cloud platforms are offered “as a service”, meaning that you can use them over the Internet with no need to ever install, upgrade or host. Cloud platforms are readily distinguished from other platforms, which require installations, uploads, downloads and managed hosting. As-a-service means that cloud platforms are easy to use. More important, if you build cloud software on top of a cloud platform, then your solution is inherently cloud-enabled, taking advantage of underlying cloud infrastructure, elasticity and as-a-service models. 

Benefits of Cloud Platform: 

The benefits are many:

• Lower costs – In some cases, a cloud platform can reduce costs by 80% or more, because non-core code is already engineered;

• Lower risks – Likewise, a cloud platform can reduce risks by as much, because common functions are already tested, sometimes over a period of years;

• Faster time-to-market – Cloud platforms dramatically reduce time-to-market, because they serve as a launch pad for software engineering efforts;

• Higher profit margins – Software developers and system integration firms can deliver more for substantially less, thus higher margins on fixed price contracts;

• Rapid prototyping – Create and deploy concept applications without writing code;

• Higher security and interoperability – NIST indicates that the cloud suffers from major security issues, largely because vendors are implementing disparate and unproven security models. Cloud platforms provide a common, proven security model. If cloud software uses the platform, then it is inherently secure.

Build apps with PaaS, not infrastructure.

As discussed earlier, Platform as a Service (PaaS) eliminates the expense and complexity of evaluating, buying, configuring, and managing all the hardware and software needed for custom-built applications. let understand it as: 

                                

Why PaaS is being adopted: The traditional application model is broken.

Building and running on-premise applications has always been complex, expensive, and slow. Each application required hardware, an operating system, a database, middle ware, Web servers, and other software. Once the stack was assembled, a team of developers had to navigate frameworks like J2EE and .NET. A team of network, database, and system management experts was needed to keep everything up and running. Inevitably, a business requirement would require a change to the application, which would then kick off another lengthy development, test, and redeployment cycle.

Additionally, large companies often needed specialized facilities to house their data centers and a team to maintain them. Enormous amounts of electricity also were needed to power the servers as well as the systems to keep them cool. Finally, a failover site was needed to mirror the data center so information could be replicated in case of a disaster.

Applications built with this complexity and infrastructure are difficult to scale for usage spike demands, brittle to update as the business needs change, and are difficult to make mobile and social.

The new model: Cloud apps.

Just as Amazon.com, eBay, Google, iTunes, and YouTube made it possible to access new capabilities and new markets through a Web browser, PaaS offers a faster, more cost-effective model for application development and delivery.

PaaS provides all the infrastructure needed to develop and run applications over the Internet. Users can access custom apps built in the cloud, just like their SaaS apps, while IT departments and ISVs can focus on innovation instead of complex infrastructure. By leveraging PaaS, organizations can redirect a significant portion of their budgets from “keeping the lights on” to creating applications that provide real business value.

PaaS is driving a new era of mass innovation and business agility. For the first time, developers can focus on application expertise for their business, not managing complex hardware and software infrastructure.

 Software-as-a-Service, or SaaS :

Software as a service (or SaaS) is a way of delivering applications over the Internet—as a service. Instead of installing and maintaining software, you simply access it via the Internet, freeing yourself from complex software and hardware management.

SaaS applications are sometimes called Web-based software, on-demand software, or hosted software. Whatever the name, SaaS applications run on a SaaS provider’s servers. The provider manages access to the application, including security, availability, and performance.

SAAS: THE PAYOFF

SaaS customers have no hardware or software to buy, install, maintain, or update. Access to applications is easy: You just need an Internet connection.

SaaS CHARACTERISTICS

A good way to understand the SaaS model is by thinking of a bank, which protects the privacy of each customer while providing service that is reliable and secure—on a massive scale. A bank’s customers all use the same financial systems and technology without worrying about anyone accessing their personal information without authorization.

A “bank” meets the key characteristics of the SaaS model:

MULTITENANT ARCHITECTURE

A multitenant architecture, in which all users and applications share a single, common infrastructure and code base that is centrally maintained. Because SaaS vendor clients are all on the same infrastructure and code base, vendors can innovate more quickly and save the valuable development time previously spent on maintaining numerous versions of outdated code.

EASY CUSTOMIZATION

The ability for each user to easily customize applications to fit their business processes without affecting the common infrastructure. Because of the way SaaS is architected, these customizations are unique to each company or user and are always preserved through upgrades. That means SaaS providers can make upgrades more often, with less customer risk and much lower adoption cost.

BETTER ACCESS

Improved access to data from any networked device while making it easier to manage privileges, monitor data use, and ensure everyone sees the same information at the same time.

SaaS HARNESSES THE CONSUMER WEB

Anyone familiar with Amazon.com or My Yahoo! will be familiar with the Web interface of typical SaaS applications. With the SaaS model, you can customize with point-and-click ease, making the weeks or months it takes to update traditional business software seem hopelessly old fashioned.

SaaS TRENDS

Organizations are now developing SaaS integration platforms (or SIPs) for building additional SaaS applications. The consulting firm Saugatuck Technology calls this the “third wave” in software adoption: when SaaS moves beyond standalone software functionality to become a platform for mission-critical applications.