"Platform as a Service (PaaS) is .... a software distribution model in which applications are hosted by a vendor or service provider and made available to customers over the Internet .... PaaS presentations and articles from platformasaservice.com "PaaS applications are also referred to as on-demand, Web-based, or software as a service (or SaaS) solutions ..."† SalesForce.com, a PaaS provider, demonstrates the confusion between various cloud computing models.†"PaaS solutions are development platforms for which the development tool itself is hosted in the cloud and accessed through a browser...." PaaS presented by th CEO of provider Wavemaker

Platform As A Service

Definition: Platform as a Service (PaaS) is one of three main forms of cloud computing, where companies rent hardware and software from a third party. The platform is accessed across a private network or the internet and used to build applications rather than owning, running and developing on an internal IT infrastructure.



PaaS in Relation to Other Cloud Computing Models

There are three main models in the cloud computing arena. Working up from the bottom there is infrastructure as a service (IaaS), platform as a service (PaaS) and then software as a service (SaaS). With IaaS companies rent pure servers with operating systems pre-loaded, storage, network access and very little else. Organisations then load and configure their own applications and data.

SaaS is the polar opposite. Organisations rent an application and the third party providing it takes care of everything required to support that application, configuring hardware and software, providing database engines, file systems and everything else required. All the customer needs to provide are internet capable PCs and local printing services.

Identifying PaaS

PaaSPaaS sits in the middle of these two models. Essentially a company rents the hardware, operating systems, storage and network capacity that IaaS provides but also software servers and applications environments. This gives customers a platform on which they can load their data and start the developing applications they need. But being between IaaS and SaaS means that there is a great deal of overlap at both ends of the PaaS spectrum. There is no real agreement on what PaaS is and where these three forms start and stop so perhaps an example is the best way to get the idea across.

A Working PaaS Example

Salesforce.com represents perhaps one of the most successful and clearest examples of SaaS. Companies rent space on their customer relationship management system (CRM) and log onto the website without having to download or install any software. Everything is provided by the company and the only thing the customer organisation has to do is load their data and configure their preferences.

But Salesforce.com also sells a PaaS offering, Force.com. By stripping away the top layer of their CRM application and adding configuration tools Salesforce.com offers customers the ability to build their own business applications. These applications can access databases, use workflow concepts, have user interfaces and be built and deployed rapidly.

Business Drivers for PaaS

As with most cloud computing applications cost is the major driver forPlatform As A Service customers signing up to a PaaS offering rather than building (or continuing to develop) their own business applications. Instead of maintaining an IT infrastructure that covers the whole stack of the computing environment from hardware up to applications, organisations can offload the cost and administration hassle of looking after the bottom half of that stack, renting is from a PaaS provider.

The IT department therefore doesnít have to bother themselves  looking after hardware, storage, networks, operating systems and software servers, they can spend their time building business applications. This makes sense for a lot of companies as this is where IT can deliver value to the business.

Portability of Assets and PaaS

It's not all plain sailing with PaaS though. Organisations considering using PaaS as a strategic tool for developing applications need to consider the stability of the company providing the service. A number of PaaS providers have gone to the wall as the market matures and the economic environment makes startup survival more difficult.

Organisations need to pay particular attention to the portability of the applications they develop. If a provider does go to the wall, becomes unreliable or undesirable in some way (perhaps upping prices once you are locked in) there needs to be a clear exit path for the customer organisation.

Cost Savings With PaaS

The cost savings for PaaS, in common with other cloud computing models, are based on renting from a large provider which allows customers to benefit from the economies of scale that the provider can achieve. Cost savings are difficult to compare between different PaaS providers and with other ways of developing applications, such as in-house development or outsourcing to a software house. As off-shore development becomes more capable and still remains cheap, PaaS faces considerable competition from traditional models. And, vitally, organisations using these more traditional models own and control their code and applications.

There are hidden costs in adopting PaaS as well. Some of these are related to the 'what-if' scenarios of a PaaS provider going to the wall or becoming a liability. But others are not. For example, building any strategic relationship requires people to work at the interface between the two companies.

Eyes Wide Open

Don't be fooled by the ease of use that PaaS offerings present. This is a strategic relationship and if it isnít treated as such from board level down then there is a high risk that cost savings and efficiency gains will not be as good as expected. Analyse every aspect of how the company will work with a PaaS provider and the output from such a project before making a decision.