Published on WSO2 Oxygen Tank (http://wso2.org)
by Ayanthi Anandagoda
Table of Contents
- Cloud Computing
- Software as a Service (SaaS)
- Hardware as a Service (HaaS)
- Platform as a Service (PaaS)
- at Cross Roads..
Cloud computing essentially encapsulates the following three concepts: pay-as-you-go, on-demand and on the Net. It is the computing model of the day, where the use of IT is billed like a utility and hence the term utility computing. Cloud computing is a part of the on-demand model for computing that allows companies to focus on creating true business value rather than delve on setting up and maintaining IT infrastructure to get going.
How do we then, relate cloud computing to SaaS, PaaS and HaaS? As you dig deeper it becomes apparent that SaaS, PaaS and HaaS are different categories of cloud computing. Where SaaS refers to applications in the cloud, PaaS refers to the platforms in the cloud while HaaS refers to the infrastructure in the cloud.
2. Software as a Service..
The concept of 'Software as a Service' or SaaS, is an application delivery model with vendors hosting Web-based applications on the Internet and consumers consuming them on line. Technologies such as Web services and REST  play an integral role in the development of SaaS applications.
The origins of the popular CamelCase term goes back to a white paper published by the Software & Information Industry's eBusiness Division in 2001 titled "Strategic Backgrounder: Software as a Service" , in which they discussed, “the delivery, management and payment of software by Application Service Providers (ASPs) as a service rather than a product..” with users 'subscribing' for the use of software rather than purchasing them upfront.
Despite the hype back in the days, the ASP model failed to take off as anticipated by the originators largely due to the unavailability of network and Web being untested grounds for many. Today, tables have clearly turned with Internet access at lightening speeds, increased habitats on the Web and the increased adoption of open standards.
Web 2.0 addressed largely the Web-based socializing and consumer-oriented software domain but not SaaS. The list of vertical industries qualifying for SaaS application model include Customer Relationship Management (CRM) systems, Supply Chain Management (SCM) systems, Human Resources Management (HRM) systems, video conferencing, accounting and various others.
SaaS presents a number of licensing and pricing models for the vendors to choose from that includes pay-as-you-go, subscription-based, revenue-based, usage/transaction-based and other. Some even go as far as offering complete services free of charge preferring to monetize with ads only.
3. Hardware as a Service..
The concept of Hardware as a Service' or HaaS refers to, the virtualization of the data center. It appears to be that HaaS provides the real estate support while SaaS provides the application functionality in the journey towards cloud computing supremacy.
With striking similarities to hardware leasing, HaaS is a model in which the vendor manages the lease as opposed to the customer that helps keep service calls to an absolute minimum.
Earlier this year, Apple announced its slightly different flavor of HaaS that promises to improve old hardware with software upgrades an act that was already adopted by Microsoft on Zune devices, Nintendo on wii and Sony on its BlueRay playback on the Playstation.
4. Platform as a Service..
In the next logical evolution of computing in the cloud comes as an integrated platform to build, test, and deploy custom applications that we called the Platform as a Service (PaaS).
The concept of 'Platform as a Service' is a form of cloud computing delivers development environments as a service rather than offering full-blown applications. Pioneered by Amazon, Google already has an offer with the Google App engine, where you can sign up for a free account use up to 500MB of persistent storage, CPU and bandwidth for about 5 million page views a month. Sun is on its way with their offering of Platform as a Service in what they called Project Caroline.
- Utility Computing refers to making computing resources available as a metered service.
- Grid Computing refers to an infrastructure in which networked computers are able to access and utilize the power of one another
- Elasticity refers to the ability to dynamically acquire or release computing resources on-demand
SaaS is predominantly looked at as an application delivery model, as opposed to the concept of SOA (Service Oriented Architecture) - an architectural strategy weaving together services to create business processes. So, what have they got in common?
On one side, the flexible and scalable pedigree of SOA brings value to SaaS - in terms of loosely coupled, contracted services that empowers SaaS providers more efficiently compete in the marketplace against packaged, on-premise software vendors in terms of price, flexibility and other service quality offerings. As demand for scalability and flexibility mounts, SaaS can only serve in the short term without SOA offerings to enable them optimize the construction and operation of SaaS services for the long run.
On the other side of the equation, increasingly many enterprises expect SaaS be made available for their SOA implementations without getting bogged down in development. As we see, although the initial impressions of the cloud computing model was all about delivering software, the transformation is far more fundamental and deep routed in SOA.
The intersection, has been inevitable. The two forms have converged and have already begun to fuse great possibilities for the enterprise.
Is SaaS, cloud computing and PaaS serious enough for the enterprise to build and deploy business applications?
- virtualization of computing power
- on demand service coupled with a pay-per-use business model yielding to economies of scale
- increased scalability
- ability to leverage power of SOA
- reduced startup times specially for the Small Office Home Office customer(SOHO), who no longer has to bear all the costs of infrastructure and maintenance.
- single point of accountability
- rich application functionality at dramatically low costs
- removes the need to over-buy in terms of "safety net" capacities to handle periodic traffic spikes
Cloud computing seem convincing enough. Buy how about security and privacy?
The concern inevitably raises the question "how much do we need to know about the services we acquire or consume from other sources?To this point I'd say that the companies offering cloud computing services will live and die by their reputations. As cloud computing leaves users to feel that they lose a degree of control over their often-sensitive information - it would be for the cloud operators to convince otherwise.
There are addtional concerns that include concerns of how well the popular pay-as-you-go payment model is defined, as services consumption variables become complex with tiers of service constraints being added.
- Amazon Web Services: “..capitalizes on Amazon's combination of computational skills and operational savvy. It piggybacks on a multi billion-dollar IT infrastructure. And it pulls in a whole new category of customers looking for rock-solid scalable computing on demand — blue-chip startups like Zillow and PowerSet, kids in garages building the next Google, even adventurous corporate IT jocks looking to offload some of the drudgery.” 
- Recently announced IBM's cloud computing offering dubbed 'Blue Cloud' is expected offer Enterprise Data Center facilities to the financial services.To have Oracle endorsing such a concept is a landmark in itself. Cloud computing offers an economic advantage of being able to leverage the provider’s shared infrastructure without having to own the major cost of directly supporting a widely distributed user base. the case for doing it yourself is progressively getting weaker and weaker. complementary synergies between these two powerful software approaches Web 2.0 offers a face to SOA:
- The Sun Grid Compute Utility: Based on open-source technologies such as Solaris and various Java technologies, Sun Grid is an on-demand grid computing service operated by Sun Microsystems.
- Sales Force: Founded in 1999 by Marc Benioff (an ex-Oracle employee) the company is headquartered in San Francisco, California and is 'The Leader in On-Demand Customer Relationship Management (CRM)'. Its AppExchange allows external developers to create extensions that'll link them into the core Salesforce.com system. These extensions typically include varieties of sales and financial tools.
- Oracle aims to package a range of Oracle products into a coherent platform that ISVs can build their SaaS offerings on. Just a little over a month ago Oracle launched their latest on-demand CRM release - Oracle CRM On Demand.
- Microsoft's Live Mesh with design goals of unified device, data and application management.
- Netsuite hosted online business software programs include accounting, customer relationship management (CRM), enterprise resource planning (ERP) software, e-commerce and Web site development.
The on-demand model is moving everything from software applications to processing power to storage and APIs from desktops and organizational data centers to the cloud. The obstacles are more in the lines of security and privacy. Cloud operators are expected to prove themselves against rival hackers. Despite the concerns, however, the utility-style pay-by-the-drink pricing computing trend will no doubt change the society as profoundly as cheap electricity did centuries ago.
10. References & Resources:
- RiGHTSCALE Blog - Define Cloud Computing
- Strategic Backgrounder: Software as a Service
- Web 2.0 - Beyond the Conference..
- Macworld Confirms Growing Trend of 'Hardware as a Service' - WIRED
- Project Caroline - Platform.. as a Service
- Service Oriented Architecture - an Overview
- Cloud Computing. Available at Amazon.com Today - By Spencer Reiss
- Google App Engine - Run your web applications on Google's infrastructure.
- The Big Switch - Nicholas Carr
© 2008 WSO2 Inc.