You’ve decided Cloud Computing is the way forward for your organization but what kind of service do you want and what do all those abbreviations mean? Cloud computing services are now generally categorized under three main headings: Infrastructure as a Service (IaaS), Platform as a Service (PaaS) and Software as a Service (SaaS).
Infrastructure as a Service (IaaS) typically involves the provision of servers and storage systems. These can either replace or supplement an organization's own on-premise hardware and the customer can pretty much choose to do whatever they want with the capacity they have rented. IaaS particularly appeals to organizations that may suddenly need a short-term increase in processing power. This could be a one-off event, like the end of quarter financials, when large amounts of data are being processed and need to be analyzed. Customers pay only for the processing power and storage they use and should be able to scale both up and down, as they require.
Platform as a Service (PaaS) offers a slightly more complete computing platform than IaaS. In addition to servers and storage, customers would typically rent an operating system, web server and database. This platform could be used to run the customer’s existing applications or as an environment for testing new applications, in which case programming and testing tools may be offered by the cloud provider.
Software as a Service (SaaS) allows customers to pay to use software that previously had to be installed, set up and maintained in the customer’s own data centre. With SaaS, software resides in the Cloud Service Provider’s (CSP’s) cloud data centers and users access it through the public internet. The potential benefits include not having to install and maintain the software, as well as the hardware that it runs on. Users pay regular and predictable fees, a bit like a utility bill, for the right to use the software. This way, they move from a model based on paying large sums of money for software licenses and hardware (capital expenditure or ‘capex’) to one based on more regular and predictable operating expenditures.
Nowadays, every kind of software is available as a service, from office productivity software to human resources management and other kinds of ERP software. In fact, anyone who uses a free e-mail service has used software as a service (albeit one you don’t directly pay for).