Knowing your aaS From a Tin Cup.
For the uninitiated, the terms cloud computing, SaaS, IaaS, Paas, ASP, on-demand and on-prem can be needlessly confusing. Looking at these offerings at a high level will highlight the differences, though it’s worth noting that in a new and ever-changing industry, nomenclature sometimes morphs along with the technologies. It helps to first look at the full stack. Cloud services can include all or just a few of the layers. For instance, in traditional packaged software, you manage it all—networking, storage, servers, virtualization, OS, middleware, runtime, data and applications. When you move to the cloud, you can outsource all or parts of the stack to take advantage of greater efficiencies and elasticity in scale.
Term |
Definition |
Leading Provider |
Iaas
|
Raw (block) storage, firewalls, load balancers and networks, on demand from large pools installed in data centers. Accommodates LAN or WAN connectivity, in carrier clouds or via dedicated VPNs. |
Amazon Web Services Rackspace Red Hat Google Compute Engine |
Paas
|
Networks, servers and storage that facilitate deployment of web-based applications and services. Usually includes IaaS layers as well. |
GoodData Google App Engine Heroku Force.com |
SaaS
|
Software and associated data centrally hosted in the cloud, typically accessed by users using a thin client via a web browser. Like an ASP, but usually multi-tenant, rather than single tenant. |
GoodData Salesfore CRM ADP |
On-Prem |
The “old way,” where the full stack is contained on your servers. Data may be accessed and available via cloud clients, but you maintain control of everything behind your firewall. |
MS Exchange MS Office IMB Cognos PeopleSoft |
We left “On-Demand” out on purpose. Technically, it means that resources are queued up and ready for use when you need them. This attribute could apply to a managed server environment, not just a cloud service, however, the implication of on-demand is that you can scale up or down at the touch of a button. IaaS, PaaS and SaaS are all on-demand services.
Now that we’ve covered our aaSes, anything else you’d like to see us address?
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