Several different flavors of cloud computing have emerged and each has its pros and cons. add to these the plethora of acronyms created by vendors and it can be confusing to find the best option.
The three main types of cloud computing are iaas, paas, and saas: infrastructure, platform, and software as a service, respectively. When you look closer, you’ll see that what will decide this argument is your own company’s needs and comfort level.
These services are made possible by virtualization, the ubiquity of high-speed networks, and the capabilities of today’s browsers. With these things in place, it becomes less necessary to own your own infrastructure, or even own your own software. you can get what you need from the cloud, when you need it.
The easiest way to understand these as-a-service offerings is to start with saas, the most abstract layer and the one you may already be using today, even on a personal level. a simple example of saas is an online email service, such as gmail. if you use gmail, you are not hosting your own email server. It is hosted by google and you simply access it through your browser as a client. But email is just one application your business uses, and today there are online applications for many business purposes.
saas is really geared towards the end users in your organization and doesn’t require much to get started. the provider calculates how many resources to dedicate to your use of the application. the provider notices the servers, the virtual machines, the network equipment, everything. just point your browser at it.
iaas is at the other end of the cloud spectrum. In this scenario, you want to maintain control of your software environment, but you don’t want to maintain any teams. you don’t want to have to buy servers and put them in a climate-controlled room or anything like that. instead, go to an iaas provider and request a virtual machine.
you can put whatever software you want on it. on the back end, the provider provides you with storage or other resources as you need them. This is made easier by virtualization technologies, which separate physical drives and such from the virtual machine it’s running on. iaas is available from amazon ec2, ibm, and many others, but care must be taken when choosing a provider.
paas is somewhere between iaas and saas. it is not a finished product, like saas, and it is not a tabula rasa, like iaas. paas provides application developers with hooks and tools to develop on that particular platform. For example, Windows Azure from Microsoft gives you tools to develop mobile apps, social apps, websites, games, and more. you build these things, but you use the api’s and tools to connect them to the blue environment and run them there.
The confusing thing is that marketers have hijacked the “as a service” craze (just look at the many iterations of maas). most of these are really saas types, with variations on the “software” part.
In the end, saas and its many types may become so abused that we stop referring to it as a cloud thing. after all, even what we normally think of as, say, an e-commerce website is a kind of software as a service, with bits of software running in the background that the user never sees except through the graphical user interface that is the web page.
iaas and paas will be the two big classes of cloud computing, each of which will attract a different set of customers with different technical skills. And once the industry gets more comfortable with this whole cloud concept, the real argument going forward will be: how much of your computing do you trust to other providers, and how much of it stays in-house?