SPI Models – Most Used Cloud Computing Service

Cloud Computing

Cloud ComputingThe SPI Model, an acronym for SoftwarePlatform and Infrastructure, refers to one of three services offered under the rubric of cloud computing. Each of these services has a distinctive purpose then again, what they each offer can overlap. Furthermore, it’s not unusual to have “hybrid” services that provide a complicated amalgamation of these services.

Important Concepts as Foundations for These Services

Before delving into each service and which is the most used, the following preliminaries should be intimately understood:

  • Cloud computing differs from traditional computing by subscribing to these 5 delineations:
    1. A clear abstraction of electronic infrastructure
    2. Democratization of resources
    3. Provision of a service-oriented architecture
    4. Unique aspects of dynamism and elasticity
    5. Provision of a unique “utility model” of allocation and consumption
  • These services can be private, public, managed or hybrid.
  • These are ever-evolving systems/concepts and, therefore, difficult to pinhole or expertly circumscribe.
  • There are still many myths/misconceptions that need to be avoided.
  • Cloud computing has opened up areas of opportunity that were not reachable by any other means, e.g., greatly expanding data storage/management capacity software experimentation with greatly reduced risk; etc.
  • Security concerns are some of the few obstacles standing in the way of complete cloud computing embracement these include:
    1. Compliance & audit
    2. Information lifecycle management
    3. Storage retrieval/accessibility
    4. Portability & interoperability
    5. Disaster recovery
    6. Encryption technology
    7. Enterprise risk management and governance
    8. Data center safety/accountability and transparency

A Brief Discussion of the Three Services

SaaS – Software as a Service

Simply put, this is software that can be accessed on an as-needed basis and paid for in relation to how much or how often it is accessed. These programs can be used directly using a Web browser of your choice and do not require downloads, installations or maintenance on the part of the user.

The benefits to such programs are multifaceted and extensive, ostensibly allowing small operations to access many otherwise expensive programs/software on an as-needed basis. Also, runtime, O/S, virtualization, servers, storage, networking, etc., can all be delegated to third party vendors. Examples of SaaS include Google’s Gmail, Cornerstone OnDemand and Netsuite.

PaaS – Platform as a Service

This service lets software developers try out or experiment with new programs/software before putting it on the market; it is also a way for small operations to access many programs while keeping investment in hardware to a minimum. To be more technical, these are virtual computational platforms that can be accessed 24/7 from anywhere. Users thereof manage data and applications while the vendor, as in SaaS, manage virtualization, servers, O/S, middleware, etc. Some examples of PaaS include Microsoft’s Azure and Google’s App Engine.

IaaS – Infrastructure as a Service

Of all three services, this is the most comprehensive. IaaS delivers to client’s virtual computer infrastructure (networking, storage, etc.) as outsourced services billed according to usage, thus potentially saving thousands of dollars and giving small operations greater capacity. This service puts more of a management (data, application, runtime, O/S, middleware, etc.) burden on users (compared to SaaS and PaaS).

Usage Comparison of the Three

The oldest of the three, SaaS is probably the most used service. Software, after all, is still the backbone of most operations, as well as one of the most affordable IT enterprise tools. SaaS unlie PaaS and IaaS, furthermore, is a product the general public might purchase a subscription to-whereas the others are almost strictly for the enterprise. In other words, the market is biggest for SaaS.

This is so in spite of the fact that PaaS has reached 1.2 billion in usage sales.


Cloud computing is here to stay that much is clear. What the SPI model has done, though, is provide simplified virtual constructs that can be understood readily, even by non-IT professionals. As these services are better understood and more intricately/creatively utilized, the possibilities afforded to users will be greatly enhanced. Already, users are finding ways to combine services, as are technology vendors and developers. At this point, it’s not a question of which of these services will become more popular but which will professionals be able to afford to not use. Only time, though, can answer that question.

What is your rating for this article?
- Total: 0 Average: 0

Leave a Reply